drm/amd/amdgpu: add pm lock to debugfs mmio entry

Adds support for PM locks around access to registers that might
have race conditions on PG transistions.

Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 309e58cd1263..9b358df6e886 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2282,22 +2282,26 @@ static ssize_t amdgpu_debugfs_regs_read(struct file *f, char __user *buf,
         struct amdgpu_device *adev = f->f_inode->i_private;
         ssize_t result = 0;
         int r;
-        bool use_bank;
+        bool pm_pg_lock, use_bank;
         unsigned instance_bank, sh_bank, se_bank;
 
         if (size & 0x3 || *pos & 0x3)
                 return -EINVAL;
 
+        /* are we reading registers for which a PG lock is necessary? */
+        pm_pg_lock = (*pos >> 23) & 1;
+
         if (*pos & (1ULL << 62)) {
                 se_bank = (*pos >> 24) & 0x3FF;
                 sh_bank = (*pos >> 34) & 0x3FF;
                 instance_bank = (*pos >> 44) & 0x3FF;
                 use_bank = 1;
-                *pos &= 0xFFFFFF;
         } else {
                 use_bank = 0;
         }
 
+        *pos &= 0x3FFFF;
+
         if (use_bank) {
                 if (sh_bank >= adev->gfx.config.max_sh_per_se ||
                     se_bank >= adev->gfx.config.max_shader_engines)
@@ -2307,6 +2311,9 @@ static ssize_t amdgpu_debugfs_regs_read(struct file *f, char __user *buf,
                                         sh_bank, instance_bank);
         }
 
+        if (pm_pg_lock)
+                mutex_lock(&adev->pm.mutex);
+
         while (size) {
                 uint32_t value;
 
@@ -2332,6 +2339,9 @@ end:
                 mutex_unlock(&adev->grbm_idx_mutex);
         }
 
+        if (pm_pg_lock)
+                mutex_unlock(&adev->pm.mutex);
+
         return result;
 }