drm/i915/tgl: Fix TC-cold block/unblock sequence

The command register is the PCODE MBOX low register not the high one as
described by the spec. This left the system with the TC-cold power state
being blocked all the time. Fix things by using the correct register.

Also to make sure we retry a request for at least 600usec, when the
PCODE MBOX command itself succeeded, but the TC-cold block command
failed, sleep for 1msec unconditionally after any fail.

The change was tested with JTAG register read of the HW/FW's actual
TC-cold state, which reported the expected states after this change.

Tested-by: Nivedita Swaminathan <nivedita.swaminathan@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200805150056.24248-1-imre.deak@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 3c800aa..7946c6a 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -3927,12 +3927,13 @@ tgl_tc_cold_request(struct drm_i915_private *i915, bool block)
        int ret;
 
        while (1) {
-               u32 low_val = 0, high_val;
+               u32 low_val;
+               u32 high_val = 0;
 
                if (block)
-                       high_val = TGL_PCODE_EXIT_TCCOLD_DATA_H_BLOCK_REQ;
+                       low_val = TGL_PCODE_EXIT_TCCOLD_DATA_L_BLOCK_REQ;
                else
-                       high_val = TGL_PCODE_EXIT_TCCOLD_DATA_H_UNBLOCK_REQ;
+                       low_val = TGL_PCODE_EXIT_TCCOLD_DATA_L_UNBLOCK_REQ;
 
                /*
                 * Spec states that we should timeout the request after 200us
@@ -3951,8 +3952,7 @@ tgl_tc_cold_request(struct drm_i915_private *i915, bool block)
                if (++tries == 3)
                        break;
 
-               if (ret == -EAGAIN)
-                       msleep(1);
+               msleep(1);
        }
 
        if (ret)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2b403df..e85c6fc 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -9226,8 +9226,8 @@ enum {
 #define   DISPLAY_IPS_CONTROL                  0x19
 #define   TGL_PCODE_TCCOLD                     0x26
 #define     TGL_PCODE_EXIT_TCCOLD_DATA_L_EXIT_FAILED   REG_BIT(0)
-#define     TGL_PCODE_EXIT_TCCOLD_DATA_H_BLOCK_REQ     0
-#define     TGL_PCODE_EXIT_TCCOLD_DATA_H_UNBLOCK_REQ   REG_BIT(0)
+#define     TGL_PCODE_EXIT_TCCOLD_DATA_L_BLOCK_REQ     0
+#define     TGL_PCODE_EXIT_TCCOLD_DATA_L_UNBLOCK_REQ   REG_BIT(0)
             /* See also IPS_CTL */
 #define     IPS_PCODE_CONTROL                  (1 << 30)
 #define   HSW_PCODE_DYNAMIC_DUTY_CYCLE_CONTROL 0x1A