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[PATCHv4 RESEND] staging: vme_user: provide DMA functionality
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Dmitry Kalinkin
Oct 10, 2015, 6:30:06 PM10/10/15
to
This introduces a new dma device that provides a single ioctl call that
provides DMA read and write functionality to the user space.
Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
Cc: Igor Alekseev <igor.a...@itep.ru>
---
In the last reply Martyn suggested a rework of this to make it use existing
bus/vme/ctl instead of creating a new bus/vme/dma%i device and also dynamically
allocate a dma resource in each request.
I think this doesn't need those adjustments. I think that dynamic allocation
doesn't solve any practical problem that isn't caused by current kernel api.
I also think that separate device is a good feature because it allows for
discovery of dma capatibility from userspace. The interface with separate
chardev also allows to provide DMA read() and write() syscalls that can
come handy in pair with /bin/dd.
---
drivers/staging/vme/devices/vme_user.c | 201 ++++++++++++++++++++++++++++++++-
drivers/staging/vme/devices/vme_user.h | 11 ++
2 files changed, 209 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 9cca97a..5cc782e 100644
--- a/drivers/staging/vme/devices/vme_user.c
+++ b/drivers/staging/vme/devices/vme_user.c
@@ -79,15 +79,18 @@ static unsigned int bus_num;
* We shall support 4 masters and 4 slaves with this driver.
*/
#define VME_MAJOR 221 /* VME Major Device Number */
-#define VME_DEVS 9 /* Number of dev entries */
+#define VME_DEVS 10 /* Number of dev entries */
#define MASTER_MINOR 0
#define MASTER_MAX 3
#define SLAVE_MINOR 4
#define SLAVE_MAX 7
#define CONTROL_MINOR 8
+#define DMA_MINOR 9
-#define PCI_BUF_SIZE 0x20000 /* Size of one slave image buffer */
+#define PCI_BUF_SIZE 0x20000 /* Size of one slave image buffer */
+
+#define VME_MAX_DMA_LEN 0x4000000 /* Maximal DMA transfer length */
/*
* Structure to handle image related parameters.
@@ -112,7 +115,7 @@ static const int type[VME_DEVS] = { MASTER_MINOR, MASTER_MINOR,
MASTER_MINOR, MASTER_MINOR,
SLAVE_MINOR, SLAVE_MINOR,
SLAVE_MINOR, SLAVE_MINOR,
- CONTROL_MINOR
+ CONTROL_MINOR, DMA_MINOR
};
struct vme_user_vma_priv {
@@ -343,6 +346,168 @@ static loff_t vme_user_llseek(struct file *file, loff_t off, int whence)
return -EINVAL;
}
+static int vme_user_sg_to_dma_list(const struct vme_dma_op *dma_op,
+ struct sg_table *sgt,
+ int sg_count, struct vme_dma_list *dma_list)
+{
+ ssize_t pos = 0;
+ struct scatterlist *sg;
+ int i, ret;
+
+ for_each_sg(sgt->sgl, sg, sg_count, i) {
+ struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
+ dma_addr_t hw_address = sg_dma_address(sg);
+ unsigned int hw_len = sg_dma_len(sg);
+
+ vme_attr = vme_dma_vme_attribute(dma_op->vme_addr + pos,
+ dma_op->aspace,
+ dma_op->cycle,
+ dma_op->dwidth);
+ if (!vme_attr)
+ return -ENOMEM;
+
+ pci_attr = vme_dma_pci_attribute(hw_address);
+ if (!pci_attr) {
+ vme_dma_free_attribute(vme_attr);
+ return -ENOMEM;
+ }
+
+ switch (dma_op->dir) {
+ case VME_DMA_MEM_TO_VME:
+ src = pci_attr;
+ dest = vme_attr;
+ break;
+ case VME_DMA_VME_TO_MEM:
+ src = vme_attr;
+ dest = pci_attr;
+ break;
+ }
+
+ ret = vme_dma_list_add(dma_list, src, dest, hw_len);
+
+ /*
+ * XXX VME API doesn't mention whether we should keep
+ * attributes around
+ */
+ vme_dma_free_attribute(vme_attr);
+ vme_dma_free_attribute(pci_attr);
+
+ if (ret)
+ return ret;
+
+ pos += hw_len;
+ }
+
+ return 0;
+}
+
+static enum dma_data_direction vme_dir_to_dma_dir(unsigned vme_dir)
+{
+ switch (vme_dir) {
+ case VME_DMA_VME_TO_MEM:
+ return DMA_FROM_DEVICE;
+ case VME_DMA_MEM_TO_VME:
+ return DMA_TO_DEVICE;
+ }
+
+ return DMA_NONE;
+}
+
+static ssize_t vme_user_dma_ioctl(unsigned int minor,
+ const struct vme_dma_op *dma_op)
+{
+ unsigned int offset = offset_in_page(dma_op->buf_vaddr);
+ unsigned long nr_pages;
+ enum dma_data_direction dir;
+ struct vme_dma_list *dma_list;
+ struct sg_table *sgt = NULL;
+ struct page **pages = NULL;
+ long got_pages;
+ ssize_t count;
+ int retval, sg_count;
+
+ /* Prevent WARN from dma_map_sg */
+ if (dma_op->count == 0)
+ return 0;
+
+ /*
+ * This is a voluntary limit to prevent huge allocation for pages
+ * array. VME_MAX_DMA_LEN is not a fundamental VME constraint.
+ */
+ count = min_t(size_t, dma_op->count, VME_MAX_DMA_LEN);
+ nr_pages = (offset + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+ dir = vme_dir_to_dma_dir(dma_op->dir);
+ if (dir == DMA_NONE)
+ return -EINVAL;
+
+ pages = kmalloc_array(nr_pages, sizeof(pages[0]), GFP_KERNEL);
+ if (!pages) {
+ retval = -ENOMEM;
+ goto free;
+ }
+
+ sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+ if (!sgt) {
+ retval = -ENOMEM;
+ goto free;
+ }
+
+ dma_list = vme_new_dma_list(image[minor].resource);
+ if (!dma_list) {
+ retval = -ENOMEM;
+ goto free;
+ }
+
+ got_pages = get_user_pages_fast(dma_op->buf_vaddr, nr_pages,
+ dir == DMA_FROM_DEVICE, pages);
+ if (got_pages != nr_pages) {
+ pr_debug("Not all pages were pinned\n");
+ retval = (got_pages < 0) ? got_pages : -EFAULT;
+ goto release_pages;
+ }
+
+ retval = sg_alloc_table_from_pages(sgt, pages, nr_pages,
+ offset, count, GFP_KERNEL);
+ if (retval)
+ goto release_pages;
+
+ sg_count = dma_map_sg(vme_user_bridge->dev.parent,
+ sgt->sgl, sgt->nents, dir);
+ if (!sg_count) {
+ pr_debug("DMA mapping error\n");
+ retval = -EFAULT;
+ goto free_sgt;
+ }
+
+ retval = vme_user_sg_to_dma_list(dma_op, sgt, sg_count, dma_list);
+ if (retval)
+ goto dma_unmap;
+
+ retval = vme_dma_list_exec(dma_list);
+
+dma_unmap:
+ dma_unmap_sg(vme_user_bridge->dev.parent, sgt->sgl, sgt->nents, dir);
+
+free_sgt:
+ sg_free_table(sgt);
+
+release_pages:
+ if (got_pages > 0)
+ release_pages(pages, got_pages, 0);
+
+ vme_dma_list_free(dma_list);
+
+free:
+ kfree(sgt);
+ kfree(pages);
+
+ if (retval)
+ return retval;
+
+ return count;
+}
+
/*
* The ioctls provided by the old VME access method (the one at vmelinux.org)
* are most certainly wrong as the effectively push the registers layout
@@ -359,6 +524,7 @@ static int vme_user_ioctl(struct inode *inode, struct file *file,
struct vme_master master;
struct vme_slave slave;
struct vme_irq_id irq_req;
+ struct vme_dma_op dma_op;
unsigned long copied;
unsigned int minor = MINOR(inode->i_rdev);
int retval;
@@ -467,6 +633,19 @@ static int vme_user_ioctl(struct inode *inode, struct file *file,
break;
}
break;
+ case DMA_MINOR:
+ switch (cmd) {
+ case VME_DO_DMA:
+ copied = copy_from_user(&dma_op, argp,
+ sizeof(dma_op));
+ if (copied != 0) {
+ pr_warn("Partial copy from userspace\n");
+ return -EFAULT;
+ }
+
+ return vme_user_dma_ioctl(minor, &dma_op);
+ }
+ break;
}
return -EINVAL;
@@ -678,6 +857,15 @@ static int vme_user_probe(struct vme_dev *vdev)
}
}
+ image[DMA_MINOR].resource = vme_dma_request(vme_user_bridge,
+ VME_DMA_VME_TO_MEM | VME_DMA_MEM_TO_VME);
+ if (!image[DMA_MINOR].resource) {
+ dev_warn(&vdev->dev,
+ "Unable to allocate dma resource\n");
+ err = -ENOMEM;
+ goto err_master;
+ }
+
/* Create sysfs entries - on udev systems this creates the dev files */
vme_user_sysfs_class = class_create(THIS_MODULE, driver_name);
if (IS_ERR(vme_user_sysfs_class)) {
@@ -700,6 +888,9 @@ static int vme_user_probe(struct vme_dev *vdev)
case SLAVE_MINOR:
name = "bus/vme/s%d";
break;
+ case DMA_MINOR:
+ name = "bus/vme/dma0";
+ break;
default:
err = -EINVAL;
goto err_sysfs;
@@ -724,6 +915,8 @@ err_sysfs:
}
class_destroy(vme_user_sysfs_class);
+ vme_dma_free(image[DMA_MINOR].resource);
+
/* Ensure counter set correcty to unalloc all master windows */
i = MASTER_MAX + 1;
err_master:
@@ -764,6 +957,8 @@ static int vme_user_remove(struct vme_dev *dev)
}
class_destroy(vme_user_sysfs_class);
+ vme_dma_free(image[DMA_MINOR].resource);
+
for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {
kfree(image[i].kern_buf);
vme_master_free(image[i].resource);
diff --git a/drivers/staging/vme/devices/vme_user.h b/drivers/staging/vme/devices/vme_user.h
index b8cc7bc..252b1c9 100644
--- a/drivers/staging/vme/devices/vme_user.h
+++ b/drivers/staging/vme/devices/vme_user.h
@@ -48,11 +48,22 @@ struct vme_irq_id {
__u8 statid;
};
+struct vme_dma_op {
+ __u64 vme_addr; /* Starting Address on the VMEbus */
+ __u64 buf_vaddr; /* Pointer to userspace memory */
+ __u32 count; /* Count of bytes to copy */
+ __u32 aspace; /* Address Space */
+ __u32 cycle; /* Cycle properties */
+ __u32 dwidth; /* Data transfer width */
+ __u32 dir; /* Transfer Direction */
+};
+
#define VME_GET_SLAVE _IOR(VME_IOC_MAGIC, 1, struct vme_slave)
#define VME_SET_SLAVE _IOW(VME_IOC_MAGIC, 2, struct vme_slave)
#define VME_GET_MASTER _IOR(VME_IOC_MAGIC, 3, struct vme_master)
#define VME_SET_MASTER _IOW(VME_IOC_MAGIC, 4, struct vme_master)
#define VME_IRQ_GEN _IOW(VME_IOC_MAGIC, 5, struct vme_irq_id)
+#define VME_DO_DMA _IOW(VME_IOC_MAGIC, 7, struct vme_dma_op)
#endif /* _VME_USER_H_ */
--
1.8.3.1
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Please read the FAQ at http://www.tux.org/lkml/
provides DMA read and write functionality to the user space.
Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
Cc: Igor Alekseev <igor.a...@itep.ru>
---
In the last reply Martyn suggested a rework of this to make it use existing
bus/vme/ctl instead of creating a new bus/vme/dma%i device and also dynamically
allocate a dma resource in each request.
I think this doesn't need those adjustments. I think that dynamic allocation
doesn't solve any practical problem that isn't caused by current kernel api.
I also think that separate device is a good feature because it allows for
discovery of dma capatibility from userspace. The interface with separate
chardev also allows to provide DMA read() and write() syscalls that can
come handy in pair with /bin/dd.
---
drivers/staging/vme/devices/vme_user.c | 201 ++++++++++++++++++++++++++++++++-
drivers/staging/vme/devices/vme_user.h | 11 ++
2 files changed, 209 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 9cca97a..5cc782e 100644
--- a/drivers/staging/vme/devices/vme_user.c
+++ b/drivers/staging/vme/devices/vme_user.c
@@ -79,15 +79,18 @@ static unsigned int bus_num;
* We shall support 4 masters and 4 slaves with this driver.
*/
#define VME_MAJOR 221 /* VME Major Device Number */
-#define VME_DEVS 9 /* Number of dev entries */
+#define VME_DEVS 10 /* Number of dev entries */
#define MASTER_MINOR 0
#define MASTER_MAX 3
#define SLAVE_MINOR 4
#define SLAVE_MAX 7
#define CONTROL_MINOR 8
+#define DMA_MINOR 9
-#define PCI_BUF_SIZE 0x20000 /* Size of one slave image buffer */
+#define PCI_BUF_SIZE 0x20000 /* Size of one slave image buffer */
+
+#define VME_MAX_DMA_LEN 0x4000000 /* Maximal DMA transfer length */
/*
* Structure to handle image related parameters.
@@ -112,7 +115,7 @@ static const int type[VME_DEVS] = { MASTER_MINOR, MASTER_MINOR,
MASTER_MINOR, MASTER_MINOR,
SLAVE_MINOR, SLAVE_MINOR,
SLAVE_MINOR, SLAVE_MINOR,
- CONTROL_MINOR
+ CONTROL_MINOR, DMA_MINOR
};
struct vme_user_vma_priv {
@@ -343,6 +346,168 @@ static loff_t vme_user_llseek(struct file *file, loff_t off, int whence)
return -EINVAL;
}
+static int vme_user_sg_to_dma_list(const struct vme_dma_op *dma_op,
+ struct sg_table *sgt,
+ int sg_count, struct vme_dma_list *dma_list)
+{
+ ssize_t pos = 0;
+ struct scatterlist *sg;
+ int i, ret;
+
+ for_each_sg(sgt->sgl, sg, sg_count, i) {
+ struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
+ dma_addr_t hw_address = sg_dma_address(sg);
+ unsigned int hw_len = sg_dma_len(sg);
+
+ vme_attr = vme_dma_vme_attribute(dma_op->vme_addr + pos,
+ dma_op->aspace,
+ dma_op->cycle,
+ dma_op->dwidth);
+ if (!vme_attr)
+ return -ENOMEM;
+
+ pci_attr = vme_dma_pci_attribute(hw_address);
+ if (!pci_attr) {
+ vme_dma_free_attribute(vme_attr);
+ return -ENOMEM;
+ }
+
+ switch (dma_op->dir) {
+ case VME_DMA_MEM_TO_VME:
+ src = pci_attr;
+ dest = vme_attr;
+ break;
+ case VME_DMA_VME_TO_MEM:
+ src = vme_attr;
+ dest = pci_attr;
+ break;
+ }
+
+ ret = vme_dma_list_add(dma_list, src, dest, hw_len);
+
+ /*
+ * XXX VME API doesn't mention whether we should keep
+ * attributes around
+ */
+ vme_dma_free_attribute(vme_attr);
+ vme_dma_free_attribute(pci_attr);
+
+ if (ret)
+ return ret;
+
+ pos += hw_len;
+ }
+
+ return 0;
+}
+
+static enum dma_data_direction vme_dir_to_dma_dir(unsigned vme_dir)
+{
+ switch (vme_dir) {
+ case VME_DMA_VME_TO_MEM:
+ return DMA_FROM_DEVICE;
+ case VME_DMA_MEM_TO_VME:
+ return DMA_TO_DEVICE;
+ }
+
+ return DMA_NONE;
+}
+
+static ssize_t vme_user_dma_ioctl(unsigned int minor,
+ const struct vme_dma_op *dma_op)
+{
+ unsigned int offset = offset_in_page(dma_op->buf_vaddr);
+ unsigned long nr_pages;
+ enum dma_data_direction dir;
+ struct vme_dma_list *dma_list;
+ struct sg_table *sgt = NULL;
+ struct page **pages = NULL;
+ long got_pages;
+ ssize_t count;
+ int retval, sg_count;
+
+ /* Prevent WARN from dma_map_sg */
+ if (dma_op->count == 0)
+ return 0;
+
+ /*
+ * This is a voluntary limit to prevent huge allocation for pages
+ * array. VME_MAX_DMA_LEN is not a fundamental VME constraint.
+ */
+ count = min_t(size_t, dma_op->count, VME_MAX_DMA_LEN);
+ nr_pages = (offset + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+ dir = vme_dir_to_dma_dir(dma_op->dir);
+ if (dir == DMA_NONE)
+ return -EINVAL;
+
+ pages = kmalloc_array(nr_pages, sizeof(pages[0]), GFP_KERNEL);
+ if (!pages) {
+ retval = -ENOMEM;
+ goto free;
+ }
+
+ sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+ if (!sgt) {
+ retval = -ENOMEM;
+ goto free;
+ }
+
+ dma_list = vme_new_dma_list(image[minor].resource);
+ if (!dma_list) {
+ retval = -ENOMEM;
+ goto free;
+ }
+
+ got_pages = get_user_pages_fast(dma_op->buf_vaddr, nr_pages,
+ dir == DMA_FROM_DEVICE, pages);
+ if (got_pages != nr_pages) {
+ pr_debug("Not all pages were pinned\n");
+ retval = (got_pages < 0) ? got_pages : -EFAULT;
+ goto release_pages;
+ }
+
+ retval = sg_alloc_table_from_pages(sgt, pages, nr_pages,
+ offset, count, GFP_KERNEL);
+ if (retval)
+ goto release_pages;
+
+ sg_count = dma_map_sg(vme_user_bridge->dev.parent,
+ sgt->sgl, sgt->nents, dir);
+ if (!sg_count) {
+ pr_debug("DMA mapping error\n");
+ retval = -EFAULT;
+ goto free_sgt;
+ }
+
+ retval = vme_user_sg_to_dma_list(dma_op, sgt, sg_count, dma_list);
+ if (retval)
+ goto dma_unmap;
+
+ retval = vme_dma_list_exec(dma_list);
+
+dma_unmap:
+ dma_unmap_sg(vme_user_bridge->dev.parent, sgt->sgl, sgt->nents, dir);
+
+free_sgt:
+ sg_free_table(sgt);
+
+release_pages:
+ if (got_pages > 0)
+ release_pages(pages, got_pages, 0);
+
+ vme_dma_list_free(dma_list);
+
+free:
+ kfree(sgt);
+ kfree(pages);
+
+ if (retval)
+ return retval;
+
+ return count;
+}
+
/*
* The ioctls provided by the old VME access method (the one at vmelinux.org)
* are most certainly wrong as the effectively push the registers layout
@@ -359,6 +524,7 @@ static int vme_user_ioctl(struct inode *inode, struct file *file,
struct vme_master master;
struct vme_slave slave;
struct vme_irq_id irq_req;
+ struct vme_dma_op dma_op;
unsigned long copied;
unsigned int minor = MINOR(inode->i_rdev);
int retval;
@@ -467,6 +633,19 @@ static int vme_user_ioctl(struct inode *inode, struct file *file,
break;
}
break;
+ case DMA_MINOR:
+ switch (cmd) {
+ case VME_DO_DMA:
+ copied = copy_from_user(&dma_op, argp,
+ sizeof(dma_op));
+ if (copied != 0) {
+ pr_warn("Partial copy from userspace\n");
+ return -EFAULT;
+ }
+
+ return vme_user_dma_ioctl(minor, &dma_op);
+ }
+ break;
}
return -EINVAL;
@@ -678,6 +857,15 @@ static int vme_user_probe(struct vme_dev *vdev)
}
}
+ image[DMA_MINOR].resource = vme_dma_request(vme_user_bridge,
+ VME_DMA_VME_TO_MEM | VME_DMA_MEM_TO_VME);
+ if (!image[DMA_MINOR].resource) {
+ dev_warn(&vdev->dev,
+ "Unable to allocate dma resource\n");
+ err = -ENOMEM;
+ goto err_master;
+ }
+
/* Create sysfs entries - on udev systems this creates the dev files */
vme_user_sysfs_class = class_create(THIS_MODULE, driver_name);
if (IS_ERR(vme_user_sysfs_class)) {
@@ -700,6 +888,9 @@ static int vme_user_probe(struct vme_dev *vdev)
case SLAVE_MINOR:
name = "bus/vme/s%d";
break;
+ case DMA_MINOR:
+ name = "bus/vme/dma0";
+ break;
default:
err = -EINVAL;
goto err_sysfs;
@@ -724,6 +915,8 @@ err_sysfs:
}
class_destroy(vme_user_sysfs_class);
+ vme_dma_free(image[DMA_MINOR].resource);
+
/* Ensure counter set correcty to unalloc all master windows */
i = MASTER_MAX + 1;
err_master:
@@ -764,6 +957,8 @@ static int vme_user_remove(struct vme_dev *dev)
}
class_destroy(vme_user_sysfs_class);
+ vme_dma_free(image[DMA_MINOR].resource);
+
for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {
kfree(image[i].kern_buf);
vme_master_free(image[i].resource);
diff --git a/drivers/staging/vme/devices/vme_user.h b/drivers/staging/vme/devices/vme_user.h
index b8cc7bc..252b1c9 100644
--- a/drivers/staging/vme/devices/vme_user.h
+++ b/drivers/staging/vme/devices/vme_user.h
@@ -48,11 +48,22 @@ struct vme_irq_id {
__u8 statid;
};
+struct vme_dma_op {
+ __u64 vme_addr; /* Starting Address on the VMEbus */
+ __u64 buf_vaddr; /* Pointer to userspace memory */
+ __u32 count; /* Count of bytes to copy */
+ __u32 aspace; /* Address Space */
+ __u32 cycle; /* Cycle properties */
+ __u32 dwidth; /* Data transfer width */
+ __u32 dir; /* Transfer Direction */
+};
+
#define VME_GET_SLAVE _IOR(VME_IOC_MAGIC, 1, struct vme_slave)
#define VME_SET_SLAVE _IOW(VME_IOC_MAGIC, 2, struct vme_slave)
#define VME_GET_MASTER _IOR(VME_IOC_MAGIC, 3, struct vme_master)
#define VME_SET_MASTER _IOW(VME_IOC_MAGIC, 4, struct vme_master)
#define VME_IRQ_GEN _IOW(VME_IOC_MAGIC, 5, struct vme_irq_id)
+#define VME_DO_DMA _IOW(VME_IOC_MAGIC, 7, struct vme_dma_op)
#endif /* _VME_USER_H_ */
--
1.8.3.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majo...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Dmitry Kalinkin
Oct 10, 2015, 8:20:08 PM10/10/15
to
This introduces a new dma device that provides a single ioctl call that
provides DMA read and write functionality to the user space.
Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
Cc: Igor Alekseev <igor.a...@itep.ru>
---
In the last reply Martyn suggested a rework of this to make it use existing
bus/vme/ctl instead of creating a new bus/vme/dma%i device and also dynamically
allocate a dma resource in each request.
I think this doesn't need those adjustments. I think that dynamic allocation
doesn't solve any practical problem that isn't caused by current kernel api.
I also think that separate device is a good feature because it allows for
discovery of dma capatibility from userspace. The interface with separate
chardev also allows to provide DMA read() and write() syscalls that can
come handy in pair with /bin/dd.
v5:
provides DMA read and write functionality to the user space.
Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
Cc: Igor Alekseev <igor.a...@itep.ru>
---
In the last reply Martyn suggested a rework of this to make it use existing
bus/vme/ctl instead of creating a new bus/vme/dma%i device and also dynamically
allocate a dma resource in each request.
I think this doesn't need those adjustments. I think that dynamic allocation
doesn't solve any practical problem that isn't caused by current kernel api.
I also think that separate device is a good feature because it allows for
discovery of dma capatibility from userspace. The interface with separate
chardev also allows to provide DMA read() and write() syscalls that can
come handy in pair with /bin/dd.
Added a validation for dma_op argument in vme_user_sg_to_dma_list(). It is
already checked in caller but we would like to silence a warning:
drivers/staging/vme/devices/vme_user.c: In function 'vme_user_ioctl.isra.4':
>> drivers/staging/vme/devices/vme_user.c:324:7: warning: 'dest' may be used uninitialized in this function [-Wmaybe-uninitialized]
ret = vme_dma_list_add(dma_list, src, dest, hw_len);
^
drivers/staging/vme/devices/vme_user.c:296:52: note: 'dest' was declared here
struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
^
>> drivers/staging/vme/devices/vme_user.c:324:7: warning: 'src' may be used uninitialized in this function [-Wmaybe-uninitialized]
ret = vme_dma_list_add(dma_list, src, dest, hw_len);
^
drivers/staging/vme/devices/vme_user.c:296:46: note: 'src' was declared here
struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
---
drivers/staging/vme/devices/vme_user.c | 205 ++++++++++++++++++++++++++++++++-
drivers/staging/vme/devices/vme_user.h | 11 ++
2 files changed, 213 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 8e61a3b..2434e5f 100644
return -EINVAL;
}
+static int vme_user_sg_to_dma_list(const struct vme_dma_op *dma_op,
+ struct sg_table *sgt,
+ int sg_count, struct vme_dma_list *dma_list)
+{
+ ssize_t pos = 0;
+ struct scatterlist *sg;
+ int i, ret;
+
+ if ((dma_op->dir != VME_DMA_MEM_TO_VME) &&
}
+static int vme_user_sg_to_dma_list(const struct vme_dma_op *dma_op,
+ struct sg_table *sgt,
+ int sg_count, struct vme_dma_list *dma_list)
+{
+ ssize_t pos = 0;
+ struct scatterlist *sg;
+ int i, ret;
+
+ (dma_op->dir != VME_DMA_VME_TO_MEM))
struct vme_master master;
struct vme_slave slave;
struct vme_irq_id irq_req;
+ struct vme_dma_op dma_op;
unsigned long copied;
unsigned int minor = MINOR(inode->i_rdev);
int retval;
@@ -406,6 +576,19 @@ static int vme_user_ioctl(struct inode *inode, struct file *file,
struct vme_slave slave;
struct vme_irq_id irq_req;
+ struct vme_dma_op dma_op;
unsigned long copied;
unsigned int minor = MINOR(inode->i_rdev);
int retval;
break;
}
break;
+ case DMA_MINOR:
+ switch (cmd) {
+ case VME_DO_DMA:
+ copied = copy_from_user(&dma_op, argp,
+ sizeof(dma_op));
+ if (copied != 0) {
+ pr_warn("Partial copy from userspace\n");
+ return -EFAULT;
+ }
+
+ return vme_user_dma_ioctl(minor, &dma_op);
+ }
+ break;
}
return -EINVAL;
@@ -615,6 +798,15 @@ static int vme_user_probe(struct vme_dev *vdev)
}
break;
+ case DMA_MINOR:
+ switch (cmd) {
+ case VME_DO_DMA:
+ copied = copy_from_user(&dma_op, argp,
+ sizeof(dma_op));
+ if (copied != 0) {
+ pr_warn("Partial copy from userspace\n");
+ return -EFAULT;
+ }
+
+ return vme_user_dma_ioctl(minor, &dma_op);
+ }
+ break;
}
return -EINVAL;
}
}
+ image[DMA_MINOR].resource = vme_dma_request(vme_user_bridge,
+ VME_DMA_VME_TO_MEM | VME_DMA_MEM_TO_VME);
+ if (!image[DMA_MINOR].resource) {
+ dev_warn(&vdev->dev,
+ "Unable to allocate dma resource\n");
+ err = -ENOMEM;
+ goto err_master;
+ }
+
/* Create sysfs entries - on udev systems this creates the dev files */
vme_user_sysfs_class = class_create(THIS_MODULE, driver_name);
if (IS_ERR(vme_user_sysfs_class)) {
@@ -637,6 +829,9 @@ static int vme_user_probe(struct vme_dev *vdev)
}
+ image[DMA_MINOR].resource = vme_dma_request(vme_user_bridge,
+ VME_DMA_VME_TO_MEM | VME_DMA_MEM_TO_VME);
+ if (!image[DMA_MINOR].resource) {
+ dev_warn(&vdev->dev,
+ "Unable to allocate dma resource\n");
+ err = -ENOMEM;
+ goto err_master;
+ }
+
/* Create sysfs entries - on udev systems this creates the dev files */
vme_user_sysfs_class = class_create(THIS_MODULE, driver_name);
if (IS_ERR(vme_user_sysfs_class)) {
case SLAVE_MINOR:
name = "bus/vme/s%d";
break;
+ case DMA_MINOR:
+ name = "bus/vme/dma0";
+ break;
default:
err = -EINVAL;
goto err_sysfs;
@@ -661,6 +856,8 @@ err_sysfs:
name = "bus/vme/s%d";
break;
+ case DMA_MINOR:
+ name = "bus/vme/dma0";
+ break;
default:
err = -EINVAL;
goto err_sysfs;
}
class_destroy(vme_user_sysfs_class);
+ vme_dma_free(image[DMA_MINOR].resource);
+
/* Ensure counter set correcty to unalloc all master windows */
i = MASTER_MAX + 1;
err_master:
@@ -701,6 +898,8 @@ static int vme_user_remove(struct vme_dev *dev)
class_destroy(vme_user_sysfs_class);
+ vme_dma_free(image[DMA_MINOR].resource);
+
/* Ensure counter set correcty to unalloc all master windows */
i = MASTER_MAX + 1;
err_master:
Greg Kroah-Hartman
Oct 18, 2015, 12:00:06 AM10/18/15
to
On Sun, Oct 11, 2015 at 03:13:25AM +0300, Dmitry Kalinkin wrote:
> This introduces a new dma device that provides a single ioctl call that
> provides DMA read and write functionality to the user space.
>
> Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
> Cc: Igor Alekseev <igor.a...@itep.ru>
> ---
>
Ugh, trailing whitespace hurts the eyes...
> This introduces a new dma device that provides a single ioctl call that
> provides DMA read and write functionality to the user space.
>
> Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
> Cc: Igor Alekseev <igor.a...@itep.ru>
> ---
>
Anyway, I need an ack from Martyn before I can accept this type of
thing.
thanks,
greg k-h
Dmitry Kalinkin
Oct 18, 2015, 12:10:06 AM10/18/15
to
> On 2015/10/17, at 23:52, Greg Kroah-Hartman <gre...@linuxfoundation.org> wrote:
>
> On Sun, Oct 11, 2015 at 03:13:25AM +0300, Dmitry Kalinkin wrote:
>> This introduces a new dma device that provides a single ioctl call that
>> provides DMA read and write functionality to the user space.
>>
>> Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
>> Cc: Igor Alekseev <igor.a...@itep.ru>
>> ---
>>
>
> Ugh, trailing whitespace hurts the eyes...
>
> Anyway, I need an ack from Martyn before I can accept this type of
> thing.
>
> thanks,
>
> greg k-h
Martyn Welch
Oct 18, 2015, 10:40:05 AM10/18/15
to
On 11/10/15 01:13, Dmitry Kalinkin wrote:
> This introduces a new dma device that provides a single ioctl call that
> provides DMA read and write functionality to the user space.
>
> Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
> Cc: Igor Alekseev <igor.a...@itep.ru>
> ---
>
> In the last reply Martyn suggested a rework of this to make it use existing
> bus/vme/ctl instead of creating a new bus/vme/dma%i device and also dynamically
> allocate a dma resource in each request.
>
> I think this doesn't need those adjustments. I think that dynamic allocation
> doesn't solve any practical problem that isn't caused by current kernel api.
drivers using the kernel api and what resources the underlying bridge
had to make available. This driver will currently only load if all the
resources it wishes to expose to user space are available. That said,
such a modification is clearly separate from adding DMA support to user
space, so the argument is rather academic.
>
> I also think that separate device is a good feature because it allows for
> discovery of dma capatibility from userspace.
> The interface with separate
> chardev also allows to provide DMA read() and write() syscalls that can
> come handy in pair with /bin/dd.
(Generally happy with this for now, however couple of comments below.)
interface that this driver exposes and what is documented in
Documentation/devices.txt.
I think this comment either needs updating to reflect the changes
introduced in this patch, or deleted.
(As an aside:
The interface in Docmentation/devices.txt is an interesting oddity - it
existed before any VME drivers were present in the kernel. Given that
the driver at vmelinux.org hasn't been updated since some time in the
2.4 kernel series and the lack of mainlined drivers other than this one
using that interface, should we update that file to reflect the additions?
If we were to modify this driver sufficiently, so that chrdevs were
dynamically allocated for example, should we delete that entry?
)
below?
>
> #endif /* _VME_USER_H_ */
>
--
Dmitry Kalinkin
Oct 18, 2015, 2:00:09 PM10/18/15
to
On Sun, Oct 18, 2015 at 10:31 AM, Martyn Welch <mar...@welchs.me.uk> wrote:
>
>
> On 11/10/15 01:13, Dmitry Kalinkin wrote:
>>
>> This introduces a new dma device that provides a single ioctl call that
>> provides DMA read and write functionality to the user space.
>>
>> Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
>> Cc: Igor Alekseev <igor.a...@itep.ru>
>> ---
>>
>> In the last reply Martyn suggested a rework of this to make it use existing
>> bus/vme/ctl instead of creating a new bus/vme/dma%i device and also
>> dynamically
>> allocate a dma resource in each request.
>>
>> I think this doesn't need those adjustments. I think that dynamic allocation
>> doesn't solve any practical problem that isn't caused by current kernel
>> api.
>
>
> That would depend on what resources had already been allocated to other
> drivers using the kernel api and what resources the underlying bridge had to
> make available. This driver will currently only load if all the resources it
> wishes to expose to user space are available. That said, such a modification
> is clearly separate from adding DMA support to user space, so the argument
> is rather academic.
Other drives meaning vme_pio, I don't see any others. All this time
>
>
> On 11/10/15 01:13, Dmitry Kalinkin wrote:
>>
>> This introduces a new dma device that provides a single ioctl call that
>> provides DMA read and write functionality to the user space.
>>
>> Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
>> Cc: Igor Alekseev <igor.a...@itep.ru>
>> ---
>>
>> In the last reply Martyn suggested a rework of this to make it use existing
>> bus/vme/ctl instead of creating a new bus/vme/dma%i device and also
>> dynamically
>> allocate a dma resource in each request.
>>
>> I think this doesn't need those adjustments. I think that dynamic allocation
>> doesn't solve any practical problem that isn't caused by current kernel
>> api.
>
>
> That would depend on what resources had already been allocated to other
> drivers using the kernel api and what resources the underlying bridge had to
> make available. This driver will currently only load if all the resources it
> wishes to expose to user space are available. That said, such a modification
> is clearly separate from adding DMA support to user space, so the argument
> is rather academic.
we are discussing how many GE PIO boards one can plug into a crate
with or without vme_user. Most of people have zero of them.
Also, VME DMA API has no users in kernel, we are just adding one now.
>
>> I also think that separate device is a good feature because it allows
>> for
>> discovery of dma capatibility from userspace.
>
>
> Given the current user space api, that's true.
>
>> The interface with separate
>> chardev also allows to provide DMA read() and write() syscalls that can
>> come handy in pair with /bin/dd.
>
>
> But this patch doesn't implement such a feature does it?
Actually, initial (never published) version of this patch exposed
>> I also think that separate device is a good feature because it allows
>> for
>> discovery of dma capatibility from userspace.
>
>
> Given the current user space api, that's true.
>
>> The interface with separate
>> chardev also allows to provide DMA read() and write() syscalls that can
>> come handy in pair with /bin/dd.
>
>
> But this patch doesn't implement such a feature does it?
read(),write(),
and an ioctl to set the access cycle. It was working, but with subtlety for
A64 addressing. I come across some problems when using large offsets
that would not fit in signed long long. I was using FMODE_UNSIGNED_OFFSET
to fix the kernel side of things, but it seemed like userspace didn't like
the "negative" offsets. I've looked a bit at glibc sources and decided
to give up.
Now that I remember this, my original argument is kind of busted.
document is generally outdated and is not required to be updated.
First, "Last revised: 6th April 2009"
Second, the device path information is long obsolete in the light of udev.
Third, they want submissions on a separate list <dev...@lanana.org>
Fourth, "20 block Hitachi CD-ROM (under development) 0 = /dev/hitcd"
-- this is not for real.
>
> I think this comment either needs updating to reflect the changes introduced
> in this patch, or deleted.
>
> (As an aside:
>
> The interface in Docmentation/devices.txt is an interesting oddity - it
> existed before any VME drivers were present in the kernel. Given that the
> driver at vmelinux.org hasn't been updated since some time in the 2.4 kernel
> series and the lack of mainlined drivers other than this one using that
> interface, should we update that file to reflect the additions?
>
> If we were to modify this driver sufficiently, so that chrdevs were
> dynamically allocated for example, should we delete that entry?
> )
Had same thoughts. I've concluded that it's not worth (see above).
> I think this comment either needs updating to reflect the changes introduced
> in this patch, or deleted.
>
> (As an aside:
>
> The interface in Docmentation/devices.txt is an interesting oddity - it
> existed before any VME drivers were present in the kernel. Given that the
> driver at vmelinux.org hasn't been updated since some time in the 2.4 kernel
> series and the lack of mainlined drivers other than this one using that
> interface, should we update that file to reflect the additions?
>
> If we were to modify this driver sufficiently, so that chrdevs were
> dynamically allocated for example, should we delete that entry?
> )
But, I guess, that is never coming around anyway.
Dmitry Kalinkin
Oct 18, 2015, 2:20:07 PM10/18/15
to
This introduces a new dma device that provides a single ioctl call that
provides DMA read and write functionality to the user space.
Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
Cc: Igor Alekseev <igor.a...@itep.ru>
---
provides DMA read and write functionality to the user space.
Signed-off-by: Dmitry Kalinkin <dmitry....@gmail.com>
Cc: Igor Alekseev <igor.a...@itep.ru>
---
v5:
Added a validation for dma_op argument in vme_user_sg_to_dma_list(). It is
already checked in caller but we would like to silence a warning:
drivers/staging/vme/devices/vme_user.c: In function 'vme_user_ioctl.isra.4':
>> drivers/staging/vme/devices/vme_user.c:324:7: warning: 'dest' may be used uninitialized in this function [-Wmaybe-uninitialized]
ret = vme_dma_list_add(dma_list, src, dest, hw_len);
^
drivers/staging/vme/devices/vme_user.c:296:52: note: 'dest' was declared here
struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
^
>> drivers/staging/vme/devices/vme_user.c:324:7: warning: 'src' may be used uninitialized in this function [-Wmaybe-uninitialized]
ret = vme_dma_list_add(dma_list, src, dest, hw_len);
^
drivers/staging/vme/devices/vme_user.c:296:46: note: 'src' was declared here
struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
v6:
Added a validation for dma_op argument in vme_user_sg_to_dma_list(). It is
already checked in caller but we would like to silence a warning:
drivers/staging/vme/devices/vme_user.c: In function 'vme_user_ioctl.isra.4':
>> drivers/staging/vme/devices/vme_user.c:324:7: warning: 'dest' may be used uninitialized in this function [-Wmaybe-uninitialized]
ret = vme_dma_list_add(dma_list, src, dest, hw_len);
^
drivers/staging/vme/devices/vme_user.c:296:52: note: 'dest' was declared here
struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
^
>> drivers/staging/vme/devices/vme_user.c:324:7: warning: 'src' may be used uninitialized in this function [-Wmaybe-uninitialized]
ret = vme_dma_list_add(dma_list, src, dest, hw_len);
^
drivers/staging/vme/devices/vme_user.c:296:46: note: 'src' was declared here
struct vme_dma_attr *pci_attr, *vme_attr, *src, *dest;
Changed dma ioctl id from 7 to 6
---
drivers/staging/vme/devices/vme_user.c | 205 ++++++++++++++++++++++++++++++++-
drivers/staging/vme/devices/vme_user.h | 11 ++
2 files changed, 213 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 8e61a3b..2434e5f 100644
--- a/drivers/staging/vme/devices/vme_user.c
+++ b/drivers/staging/vme/devices/vme_user.c
@@ -79,15 +79,18 @@ static unsigned int bus_num;
* We shall support 4 masters and 4 slaves with this driver.
*/
#endif /* _VME_USER_H_ */
--
Martyn Welch
Oct 18, 2015, 6:10:06 PM10/18/15
to
drivers. This is especially true of some industries where VME gets used.
The number of VME windows is limited, so having a user space shim either
hog or limit the number of resources available either in kernel space or
user space is not an optimal solution.
of long since deprecated practices.
That said, the comment in vme_user.c is at odds with what the code
implements after this patch is applied and that is something we very
much have control over.
attributes.
Alessio Igor Bogani
Oct 19, 2015, 4:30:06 AM10/19/15
to
Hi,
On 19 October 2015 at 00:04, Martyn Welch <mar...@welchs.me.uk> wrote:
> On 18/10/15 18:53, Dmitry Kalinkin wrote:
[...]
bunch of unpublished kernel driver for VME boards almost all built on
top of the customized old vmelinux.org stack.
We already tried to port a driver to current stack but we stuck on the
static resource management approach in particular for limited VME
windows (when the customization of the old stack was made for handle
VME windows dynamically).
Ciao,
Alessio
On 19 October 2015 at 00:04, Martyn Welch <mar...@welchs.me.uk> wrote:
> On 18/10/15 18:53, Dmitry Kalinkin wrote:
>> Other drives meaning vme_pio, I don't see any others. All this time
>> we are discussing how many GE PIO boards one can plug into a crate
>> with or without vme_user. Most of people have zero of them.
>> Also, VME DMA API has no users in kernel, we are just adding one now.
>
>
> Unfortunately not all users of Linux upstream or even publicise their
> drivers. This is especially true of some industries where VME gets used. The
> number of VME windows is limited, so having a user space shim either hog or
> limit the number of resources available either in kernel space or user space
> is not an optimal solution.
We aren't an industry but we are exactly in that position: we have a
>> we are discussing how many GE PIO boards one can plug into a crate
>> with or without vme_user. Most of people have zero of them.
>> Also, VME DMA API has no users in kernel, we are just adding one now.
>
>
> Unfortunately not all users of Linux upstream or even publicise their
> drivers. This is especially true of some industries where VME gets used. The
> number of VME windows is limited, so having a user space shim either hog or
> limit the number of resources available either in kernel space or user space
> is not an optimal solution.
bunch of unpublished kernel driver for VME boards almost all built on
top of the customized old vmelinux.org stack.
We already tried to port a driver to current stack but we stuck on the
static resource management approach in particular for limited VME
windows (when the customization of the old stack was made for handle
VME windows dynamically).
Ciao,
Alessio
Dmitry Kalinkin
Oct 19, 2015, 5:20:20 AM10/19/15
to
can either have 8 GE PIO2 boards or 4 GE PIO2 boards and any amount of boards
potentially accessible through vme_user. None of this provides for the case
when you have a crate with more than 8 GE PIO2 boards in it. Indeed, if you
have built your little proprietary system around one or two drivers so it just
fits using up all of the DMA resources and you somehow still need vme_user,
this patch will surely break it for you. But if we really care about *all*
users then there is no difference in how much resources are used by any driver,
there is always a setup for which they won’t be enough.
> The number of VME windows is limited, so having a user space shim either hog or limit the number of resources available either in kernel space or user space is not an optimal solution.
How vme_user is different from proprietary driver A to deserve such discrimination?
Would it be more optimal if proprietary driver A would take less resources that
could have otherwise been exposed to the userspace?
I agree that due to the nature of vme_user it should have some knobs to tune
it’s resource consumption, but I don’t think these should be some special ugly
knobs that only a userspace driver gets. The solution could have been to use
same kind of module params as in vme_pio2. But instead of implementing that, I
spent my time unknowingly arguing over whether mainline kernel developers
should be denied breaking certain proprietary systems lurking in the shadow of
the VME subsystem. Wonderful.
Alessio Igor Bogani
Oct 19, 2015, 5:50:06 AM10/19/15
to
Hi,
On 19 October 2015 at 11:19, Dmitry Kalinkin <dmitry....@gmail.com> wrote:
[...]
where the requests come from (user-space or kernel-space).
Ciao,
Alessio
On 19 October 2015 at 11:19, Dmitry Kalinkin <dmitry....@gmail.com> wrote:
[...]
> There is no optimal solution. In vanilla kernel you have just two drivers. You
> can either have 8 GE PIO2 boards or 4 GE PIO2 boards and any amount of boards
> potentially accessible through vme_user. None of this provides for the case
> when you have a crate with more than 8 GE PIO2 boards in it. Indeed, if you
> have built your little proprietary system around one or two drivers so it just
> fits using up all of the DMA resources and you somehow still need vme_user,
> this patch will surely break it for you. But if we really care about *all*
> users then there is no difference in how much resources are used by any driver,
> there is always a setup for which they won’t be enough.
>> The number of VME windows is limited, so having a user space shim either hog or limit the number of resources available either in kernel space or user space is not an optimal solution.
> How vme_user is different from proprietary driver A to deserve such discrimination?
> Would it be more optimal if proprietary driver A would take less resources that
> could have otherwise been exposed to the userspace?
>
> I agree that due to the nature of vme_user it should have some knobs to tune
> it’s resource consumption, but I don’t think these should be some special ugly
> knobs that only a userspace driver gets. The solution could have been to use
> same kind of module params as in vme_pio2. But instead of implementing that, I
> spent my time unknowingly arguing over whether mainline kernel developers
> should be denied breaking certain proprietary systems lurking in the shadow of
> the VME subsystem. Wonderful.
IMHO VME stack should handle bus resources dynamically not matter from
> can either have 8 GE PIO2 boards or 4 GE PIO2 boards and any amount of boards
> potentially accessible through vme_user. None of this provides for the case
> when you have a crate with more than 8 GE PIO2 boards in it. Indeed, if you
> have built your little proprietary system around one or two drivers so it just
> fits using up all of the DMA resources and you somehow still need vme_user,
> this patch will surely break it for you. But if we really care about *all*
> users then there is no difference in how much resources are used by any driver,
> there is always a setup for which they won’t be enough.
>> The number of VME windows is limited, so having a user space shim either hog or limit the number of resources available either in kernel space or user space is not an optimal solution.
> How vme_user is different from proprietary driver A to deserve such discrimination?
> Would it be more optimal if proprietary driver A would take less resources that
> could have otherwise been exposed to the userspace?
>
> I agree that due to the nature of vme_user it should have some knobs to tune
> it’s resource consumption, but I don’t think these should be some special ugly
> knobs that only a userspace driver gets. The solution could have been to use
> same kind of module params as in vme_pio2. But instead of implementing that, I
> spent my time unknowingly arguing over whether mainline kernel developers
> should be denied breaking certain proprietary systems lurking in the shadow of
> the VME subsystem. Wonderful.
where the requests come from (user-space or kernel-space).
Ciao,
Alessio
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