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Message-ID: <20231122080300.3727388-1-abhijit.gangurde@amd.com>
Date: Wed, 22 Nov 2023 13:32:59 +0530
From: Abhijit Gangurde <abhijit.gangurde@....com>
To: <gregkh@...uxfoundation.org>, <linux-kernel@...r.kernel.org>,
<Nipun.Gupta@....com>
CC: <puneet.gupta@....com>, <nikhil.agarwal@....com>,
<michal.simek@....com>, <git@....com>,
Abhijit Gangurde <abhijit.gangurde@....com>
Subject: [PATCH 1/2] cdx: create sysfs bin files for cdx resources
Resource binary file contains the content of the memory regions.
These resources<x> devices can be used to mmap the MMIO regions in
the user-space.
Co-developed-by: Puneet Gupta <puneet.gupta@....com>
Signed-off-by: Puneet Gupta <puneet.gupta@....com>
Signed-off-by: Abhijit Gangurde <abhijit.gangurde@....com>
---
Documentation/ABI/testing/sysfs-bus-cdx | 7 ++
drivers/cdx/cdx.c | 118 +++++++++++++++++++++++-
include/linux/cdx/cdx_bus.h | 10 ++
3 files changed, 134 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-cdx b/Documentation/ABI/testing/sysfs-bus-cdx
index 8c067ff99e54..e84277531414 100644
--- a/Documentation/ABI/testing/sysfs-bus-cdx
+++ b/Documentation/ABI/testing/sysfs-bus-cdx
@@ -98,6 +98,13 @@ Description:
# echo 1 > /sys/bus/cdx/devices/.../remove
+What: /sys/bus/cdx/devices/.../resource<N>
+Date: July 2023
+Contact: puneet.gupta@....com
+Description:
+ The resource binary file contains the content of the memory
+ regions. These files can be m'maped from userspace.
+
What: /sys/bus/cdx/devices/.../modalias
Date: July 2023
Contact: nipun.gupta@....com
diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
index c5873980a9d3..4edf64f9e98d 100644
--- a/drivers/cdx/cdx.c
+++ b/drivers/cdx/cdx.c
@@ -78,6 +78,8 @@ static DEFINE_MUTEX(cdx_controller_lock);
static char *compat_node_name = "xlnx,versal-net-cdx";
+static void cdx_destroy_res_attr(struct cdx_device *cdx_dev, int num);
+
/**
* cdx_dev_reset - Reset a CDX device
* @dev: CDX device
@@ -146,6 +148,7 @@ static int cdx_unregister_device(struct device *dev,
if (cdx_dev->enabled && cdx->ops->bus_disable)
cdx->ops->bus_disable(cdx, cdx_dev->bus_num);
} else {
+ cdx_destroy_res_attr(cdx_dev, MAX_CDX_DEV_RESOURCES);
kfree(cdx_dev->driver_override);
cdx_dev->driver_override = NULL;
}
@@ -641,11 +644,105 @@ static void cdx_device_release(struct device *dev)
kfree(cdx_dev);
}
+static const struct vm_operations_struct cdx_phys_vm_ops = {
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+ .access = generic_access_phys,
+#endif
+};
+
+/**
+ * cdx_mmap_resource - map a CDX resource into user memory space
+ * @fp: File pointer. Not used in this function, but required where
+ * this API is registered as a callback.
+ * @kobj: kobject for mapping
+ * @attr: struct bin_attribute for the file being mapped
+ * @vma: struct vm_area_struct passed into the mmap
+ *
+ * Use the regular CDX mapping routines to map a CDX resource into userspace.
+ *
+ * Return: true on success, false otherwise.
+ */
+static int cdx_mmap_resource(struct file *fp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ struct vm_area_struct *vma)
+{
+ struct cdx_device *cdx_dev = to_cdx_device(kobj_to_dev(kobj));
+ int num = (unsigned long)attr->private;
+ struct resource *res;
+ unsigned long size;
+
+ res = &cdx_dev->res[num];
+ if (iomem_is_exclusive(res->start))
+ return -EINVAL;
+
+ /* Make sure the caller is mapping a valid resource for this device */
+ size = ((cdx_resource_len(cdx_dev, num) - 1) >> PAGE_SHIFT) + 1;
+ if (vma->vm_pgoff + vma_pages(vma) > size)
+ return -EINVAL;
+
+ /*
+ * Map memory region and vm->vm_pgoff is expected to be an
+ * offset within that region.
+ */
+ vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
+ vma->vm_pgoff += (cdx_resource_start(cdx_dev, num) >> PAGE_SHIFT);
+ vma->vm_ops = &cdx_phys_vm_ops;
+ return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
+ vma->vm_end - vma->vm_start,
+ vma->vm_page_prot);
+}
+
+static void cdx_destroy_res_attr(struct cdx_device *cdx_dev, int num)
+{
+ int i;
+
+ /* removing the bin attributes */
+ for (i = 0; i < num; i++) {
+ struct bin_attribute *res_attr;
+
+ res_attr = cdx_dev->res_attr[i];
+ if (res_attr) {
+ sysfs_remove_bin_file(&cdx_dev->dev.kobj, res_attr);
+ kfree(res_attr);
+ }
+ }
+}
+
+#define CDX_RES_ATTR_NAME_LEN 10
+static int cdx_create_res_attr(struct cdx_device *cdx_dev, int num)
+{
+ struct bin_attribute *res_attr;
+ char *res_attr_name;
+ int ret;
+
+ res_attr = kzalloc(sizeof(*res_attr) + CDX_RES_ATTR_NAME_LEN, GFP_ATOMIC);
+ if (!res_attr)
+ return -ENOMEM;
+
+ res_attr_name = (char *)(res_attr + 1);
+
+ sysfs_bin_attr_init(res_attr);
+
+ cdx_dev->res_attr[num] = res_attr;
+ sprintf(res_attr_name, "resource%d", num);
+
+ res_attr->mmap = cdx_mmap_resource;
+ res_attr->attr.name = res_attr_name;
+ res_attr->attr.mode = 0600;
+ res_attr->size = cdx_resource_len(cdx_dev, num);
+ res_attr->private = (void *)(unsigned long)num;
+ ret = sysfs_create_bin_file(&cdx_dev->dev.kobj, res_attr);
+ if (ret)
+ kfree(res_attr);
+
+ return ret;
+}
+
int cdx_device_add(struct cdx_dev_params *dev_params)
{
struct cdx_controller *cdx = dev_params->cdx;
struct cdx_device *cdx_dev;
- int ret;
+ int ret, i;
cdx_dev = kzalloc(sizeof(*cdx_dev), GFP_KERNEL);
if (!cdx_dev)
@@ -696,7 +793,26 @@ int cdx_device_add(struct cdx_dev_params *dev_params)
goto fail;
}
+ /* Create resource<N> attributes */
+ for (i = 0; i < MAX_CDX_DEV_RESOURCES; i++) {
+ if (cdx_resource_flags(cdx_dev, i) & IORESOURCE_MEM) {
+ /* skip empty resources */
+ if (!cdx_resource_len(cdx_dev, i))
+ continue;
+
+ ret = cdx_create_res_attr(cdx_dev, i);
+ if (ret != 0) {
+ dev_err(&cdx_dev->dev,
+ "cdx device resource<%d> file creation failed: %d", i, ret);
+ goto resource_create_fail;
+ }
+ }
+ }
+
return 0;
+resource_create_fail:
+ cdx_destroy_res_attr(cdx_dev, i);
+ device_del(&cdx_dev->dev);
fail:
/*
* Do not free cdx_dev here as it would be freed in
diff --git a/include/linux/cdx/cdx_bus.h b/include/linux/cdx/cdx_bus.h
index db39835b93d2..3096c31d5b9f 100644
--- a/include/linux/cdx/cdx_bus.h
+++ b/include/linux/cdx/cdx_bus.h
@@ -154,6 +154,7 @@ struct cdx_device {
u8 bus_num;
u8 dev_num;
struct resource res[MAX_CDX_DEV_RESOURCES];
+ struct bin_attribute *res_attr[MAX_CDX_DEV_RESOURCES];
u8 res_count;
u64 dma_mask;
u16 flags;
@@ -170,6 +171,15 @@ struct cdx_device {
#define to_cdx_device(_dev) \
container_of(_dev, struct cdx_device, dev)
+#define cdx_resource_start(dev, num) ((dev)->res[(num)].start)
+#define cdx_resource_end(dev, num) ((dev)->res[(num)].end)
+#define cdx_resource_flags(dev, num) ((dev)->res[(num)].flags)
+#define cdx_resource_len(dev, num) \
+ ((cdx_resource_start((dev), (num)) == 0 && \
+ cdx_resource_end((dev), (num)) == \
+ cdx_resource_start((dev), (num))) ? 0 : \
+ (cdx_resource_end((dev), (num)) - \
+ cdx_resource_start((dev), (num)) + 1))
/**
* struct cdx_driver - CDX device driver
* @driver: Generic device driver
--
2.34.1
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