On 19-Mar-26 8:47 AM, Yang, Stanley wrote:
[AMD Official Use Only - AMD Internal Distribution Only]
-----Original Message-----
From: Lazar, Lijo <[email protected]>
Sent: Wednesday, March 18, 2026 10:43 PM
To: Yang, Stanley <[email protected]>; [email protected]
Subject: Re: [PATCH Review 1/1] drm/amdgpu: Add amdgpu_regs_pcie64
debugfs node
On 18-Mar-26 4:52 PM, Stanley.Yang wrote:
Add amdgpu_regs_pcie64 debugfs node to read/write 64bit PCIE
registers.
Signed-off-by: Stanley.Yang <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 113
++++++++++++++++++++
1 file changed, 113 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
index 6fdcd9c78324..e15b3aa02919 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -622,6 +622,111 @@ static ssize_t
amdgpu_debugfs_regs_pcie_write(struct file *f, const char __user
amdgpu_virt_disable_access_debugfs(adev);
return r;
}
+/**
+ * amdgpu_debugfs_regs_pcie64_read - Read from a 64-bit PCIE register
+ *
+ * @f: open file handle
+ * @buf: User buffer to store read data in
+ * @size: Number of bytes to read
+ * @pos: Offset to seek to
+ */
+static ssize_t amdgpu_debugfs_regs_pcie64_read(struct file *f, char __user
*buf,
+ size_t size, loff_t *pos) {
+ struct amdgpu_device *adev = file_inode(f)->i_private;
+ ssize_t result = 0;
+ int r;
+
+ if (size & 0x7 || *pos & 0x7)
+ return -EINVAL;
+
+ r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
+ if (r < 0) {
+ pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+ return r;
+ }
+
+ r = amdgpu_virt_enable_access_debugfs(adev);
+ if (r < 0) {
+ pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+ return r;
+ }
+
+ while (size) {
+ uint64_t value;
+
+ value = RREG64_PCIE_EXT(*pos);
+
+ r = put_user(value, (uint64_t *)buf);
+ if (r)
+ goto out;
+
+ result += 8;
+ buf += 8;
+ *pos += 8;
+ size -= 8;
+ }
+
+ r = result;
+out:
+ pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
+ pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
autosuspend also marks last_busy, it's no longer required to call it separately.
pm_runtime_put_autosuspend and pm_runtime_get_sync are paired, autosuspend is
used to release runtime pm usage count,
and it reads last_busy not marks last_busy.
This is a recent change -
https://lore.kernel.org/linux-pm/[email protected]/
Thanks,
Lijo
Regards,
Stanley
Thanks,
Lijo
+ amdgpu_virt_disable_access_debugfs(adev);
+ return r;
+}
+
+/**
+ * amdgpu_debugfs_regs_pcie64_write - Write to a 64-bit PCIE register
+ *
+ * @f: open file handle
+ * @buf: User buffer to write data from
+ * @size: Number of bytes to write
+ * @pos: Offset to seek to
+ */
+static ssize_t amdgpu_debugfs_regs_pcie64_write(struct file *f, const char
__user *buf,
+ size_t size, loff_t *pos) {
+ struct amdgpu_device *adev = file_inode(f)->i_private;
+ ssize_t result = 0;
+ int r;
+
+ if (size & 0x7 || *pos & 0x7)
+ return -EINVAL;
+
+ r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
+ if (r < 0) {
+ pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+ return r;
+ }
+
+ r = amdgpu_virt_enable_access_debugfs(adev);
+ if (r < 0) {
+ pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+ return r;
+ }
+
+ while (size) {
+ uint64_t value;
+
+ r = get_user(value, (uint64_t *)buf);
+ if (r)
+ goto out;
+
+ WREG64_PCIE_EXT(*pos, value);
+
+ result += 8;
+ buf += 8;
+ *pos += 8;
+ size -= 8;
+ }
+
+ r = result;
+out:
+ pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
+ pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+ amdgpu_virt_disable_access_debugfs(adev);
+ return r;
+}
/**
* amdgpu_debugfs_regs_didt_read - Read from a DIDT register @@
-1544,6 +1649,12 @@ static const struct file_operations
amdgpu_debugfs_regs_pcie_fops = {
.write = amdgpu_debugfs_regs_pcie_write,
.llseek = default_llseek
};
+static const struct file_operations amdgpu_debugfs_regs_pcie64_fops = {
+ .owner = THIS_MODULE,
+ .read = amdgpu_debugfs_regs_pcie64_read,
+ .write = amdgpu_debugfs_regs_pcie64_write,
+ .llseek = default_llseek
+};
static const struct file_operations amdgpu_debugfs_regs_smc_fops = {
.owner = THIS_MODULE,
.read = amdgpu_debugfs_regs_smc_read, @@ -1606,6 +1717,7 @@
static
const struct file_operations *debugfs_regs[] = {
&amdgpu_debugfs_gprwave_fops,
&amdgpu_debugfs_regs_didt_fops,
&amdgpu_debugfs_regs_pcie_fops,
+ &amdgpu_debugfs_regs_pcie64_fops,
&amdgpu_debugfs_regs_smc_fops,
&amdgpu_debugfs_gca_config_fops,
&amdgpu_debugfs_sensors_fops,
@@ -1623,6 +1735,7 @@ static const char * const debugfs_regs_names[] =
{
"amdgpu_gprwave",
"amdgpu_regs_didt",
"amdgpu_regs_pcie",
+ "amdgpu_regs_pcie64",
"amdgpu_regs_smc",
"amdgpu_gca_config",
"amdgpu_sensors",
