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Message-Id: <20250505223922.2682012-199-sashal@kernel.org>
Date: Mon, 5 May 2025 18:34:35 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: Dillon Varone <Dillon.Varone@....com>,
Nicholas Kazlauskas <nicholas.kazlauskas@....com>,
Wayne Lin <wayne.lin@....com>,
Daniel Wheeler <daniel.wheeler@....com>,
Alex Deucher <alexander.deucher@....com>,
Sasha Levin <sashal@...nel.org>,
harry.wentland@....com,
sunpeng.li@....com,
christian.koenig@....com,
airlied@...il.com,
simona@...ll.ch,
dillon.varone@....com,
chiahsuan.chung@....com,
joshua.aberback@....com,
Cruise.Hung@....com,
alex.hung@....com,
amd-gfx@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.12 199/486] drm/amd/display: Fix DMUB reset sequence for DCN401
From: Dillon Varone <Dillon.Varone@....com>
[ Upstream commit 0dfcc2bf269010a6e093793034c048049a40ee93 ]
[WHY]
It should no longer use DMCUB_SOFT_RESET as it can result
in the memory request path becoming desynchronized.
[HOW]
To ensure robustness in the reset sequence:
1) Extend timeout on the "halt" command sent via gpint, and check for
controller to enter "wait" as a stronger guarantee that there are no
requests to memory still in flight.
2) Remove usage of DMCUB_SOFT_RESET
3) Rely on PSP to reset the controller safely
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@....com>
Signed-off-by: Dillon Varone <Dillon.Varone@....com>
Signed-off-by: Wayne Lin <wayne.lin@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
.../drm/amd/display/dmub/src/dmub_dcn401.c | 47 ++++++++++++-------
.../drm/amd/display/dmub/src/dmub_dcn401.h | 3 +-
2 files changed, 32 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.c b/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.c
index 39a8cb6d7523c..e1c4fe1c6e3ee 100644
--- a/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.c
+++ b/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.c
@@ -63,8 +63,10 @@ static inline void dmub_dcn401_translate_addr(const union dmub_addr *addr_in,
void dmub_dcn401_reset(struct dmub_srv *dmub)
{
union dmub_gpint_data_register cmd;
- const uint32_t timeout = 30;
- uint32_t in_reset, scratch, i;
+ const uint32_t timeout_us = 1 * 1000 * 1000; //1s
+ const uint32_t poll_delay_us = 1; //1us
+ uint32_t i = 0;
+ uint32_t in_reset, scratch, pwait_mode;
REG_GET(DMCUB_CNTL2, DMCUB_SOFT_RESET, &in_reset);
@@ -75,32 +77,35 @@ void dmub_dcn401_reset(struct dmub_srv *dmub)
dmub->hw_funcs.set_gpint(dmub, cmd);
- /**
- * Timeout covers both the ACK and the wait
- * for remaining work to finish.
- *
- * This is mostly bound by the PHY disable sequence.
- * Each register check will be greater than 1us, so
- * don't bother using udelay.
- */
-
- for (i = 0; i < timeout; ++i) {
+ for (i = 0; i < timeout_us; i++) {
if (dmub->hw_funcs.is_gpint_acked(dmub, cmd))
break;
+
+ udelay(poll_delay_us);
}
- for (i = 0; i < timeout; ++i) {
+ for (; i < timeout_us; i++) {
scratch = dmub->hw_funcs.get_gpint_response(dmub);
if (scratch == DMUB_GPINT__STOP_FW_RESPONSE)
break;
+
+ udelay(poll_delay_us);
}
- /* Force reset in case we timed out, DMCUB is likely hung. */
+ for (; i < timeout_us; i++) {
+ REG_GET(DMCUB_CNTL, DMCUB_PWAIT_MODE_STATUS, &pwait_mode);
+ if (pwait_mode & (1 << 0))
+ break;
+
+ udelay(poll_delay_us);
+ }
+ }
+
+ if (i >= timeout_us) {
+ /* timeout should never occur */
+ BREAK_TO_DEBUGGER();
}
- REG_UPDATE(DMCUB_CNTL2, DMCUB_SOFT_RESET, 1);
- REG_UPDATE(DMCUB_CNTL, DMCUB_ENABLE, 0);
- REG_UPDATE(MMHUBBUB_SOFT_RESET, DMUIF_SOFT_RESET, 1);
REG_WRITE(DMCUB_INBOX1_RPTR, 0);
REG_WRITE(DMCUB_INBOX1_WPTR, 0);
REG_WRITE(DMCUB_OUTBOX1_RPTR, 0);
@@ -131,7 +136,10 @@ void dmub_dcn401_backdoor_load(struct dmub_srv *dmub,
dmub_dcn401_get_fb_base_offset(dmub, &fb_base, &fb_offset);
+ /* reset and disable DMCUB and MMHUBBUB DMUIF */
REG_UPDATE(DMCUB_SEC_CNTL, DMCUB_SEC_RESET, 1);
+ REG_UPDATE(MMHUBBUB_SOFT_RESET, DMUIF_SOFT_RESET, 1);
+ REG_UPDATE(DMCUB_CNTL, DMCUB_ENABLE, 0);
dmub_dcn401_translate_addr(&cw0->offset, fb_base, fb_offset, &offset);
@@ -151,6 +159,7 @@ void dmub_dcn401_backdoor_load(struct dmub_srv *dmub,
DMCUB_REGION3_CW1_TOP_ADDRESS, cw1->region.top,
DMCUB_REGION3_CW1_ENABLE, 1);
+ /* release DMCUB reset only to prevent premature execution */
REG_UPDATE_2(DMCUB_SEC_CNTL, DMCUB_SEC_RESET, 0, DMCUB_MEM_UNIT_ID,
0x20);
}
@@ -161,7 +170,10 @@ void dmub_dcn401_backdoor_load_zfb_mode(struct dmub_srv *dmub,
{
union dmub_addr offset;
+ /* reset and disable DMCUB and MMHUBBUB DMUIF */
REG_UPDATE(DMCUB_SEC_CNTL, DMCUB_SEC_RESET, 1);
+ REG_UPDATE(MMHUBBUB_SOFT_RESET, DMUIF_SOFT_RESET, 1);
+ REG_UPDATE(DMCUB_CNTL, DMCUB_ENABLE, 0);
offset = cw0->offset;
@@ -181,6 +193,7 @@ void dmub_dcn401_backdoor_load_zfb_mode(struct dmub_srv *dmub,
DMCUB_REGION3_CW1_TOP_ADDRESS, cw1->region.top,
DMCUB_REGION3_CW1_ENABLE, 1);
+ /* release DMCUB reset only to prevent premature execution */
REG_UPDATE_2(DMCUB_SEC_CNTL, DMCUB_SEC_RESET, 0, DMCUB_MEM_UNIT_ID,
0x20);
}
diff --git a/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.h b/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.h
index 4c8843b796950..31f95b27e227d 100644
--- a/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.h
+++ b/drivers/gpu/drm/amd/display/dmub/src/dmub_dcn401.h
@@ -169,7 +169,8 @@ struct dmub_srv;
DMUB_SF(HOST_INTERRUPT_CSR, HOST_REG_INBOX0_RSP_INT_EN) \
DMUB_SF(HOST_INTERRUPT_CSR, HOST_REG_OUTBOX0_RDY_INT_ACK) \
DMUB_SF(HOST_INTERRUPT_CSR, HOST_REG_OUTBOX0_RDY_INT_STAT) \
- DMUB_SF(HOST_INTERRUPT_CSR, HOST_REG_OUTBOX0_RDY_INT_EN)
+ DMUB_SF(HOST_INTERRUPT_CSR, HOST_REG_OUTBOX0_RDY_INT_EN) \
+ DMUB_SF(DMCUB_CNTL, DMCUB_PWAIT_MODE_STATUS)
struct dmub_srv_dcn401_reg_offset {
#define DMUB_SR(reg) uint32_t reg;
--
2.39.5
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