linux-kernel - [PATCH AUTOSEL 6.4 08/11] drm/amdgpu: Match against exact bootloader status

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Message-Id: <20230822113553.3551206-8-sashal@kernel.org>
Date:   Tue, 22 Aug 2023 07:35:50 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Lijo Lazar <lijo.lazar@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>, christian.koenig@....com,
        Xinhui.Pan@....com, airlied@...il.com, daniel@...ll.ch,
        Hawking.Zhang@....com, candice.li@....com, john.clements@....com,
        mario.limonciello@....com, Likun.Gao@....com,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.4 08/11] drm/amdgpu: Match against exact bootloader status

From: Lijo Lazar <lijo.lazar@....com>

[ Upstream commit d3de41ee5febe5c2d9989fe9810bce2bb54a3a8e ]

On PSP v13.x ASICs, boot loader will set only the MSB to 1 and clear the
least significant bits for any command submission. Hence match against
the exact register value, otherwise a register value of all 0xFFs also
could falsely indicate that boot loader is ready. Also, from PSP v13.0.6
and newer, bits[7:0] will be used to indicate command error status.

Signed-off-by: Lijo Lazar <lijo.lazar@....com>
Acked-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/amdgpu/psp_v13_0.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/psp_v13_0.c b/drivers/gpu/drm/amd/amdgpu/psp_v13_0.c
index caee76ab71105..92f2ee412908d 100644
--- a/drivers/gpu/drm/amd/amdgpu/psp_v13_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/psp_v13_0.c
@@ -136,14 +136,15 @@ static int psp_v13_0_wait_for_bootloader(struct psp_context *psp)
 	int ret;
 	int retry_loop;
 
+	/* Wait for bootloader to signify that it is ready having bit 31 of
+	 * C2PMSG_35 set to 1. All other bits are expected to be cleared.
+	 * If there is an error in processing command, bits[7:0] will be set.
+	 * This is applicable for PSP v13.0.6 and newer.
+	 */
 	for (retry_loop = 0; retry_loop < 10; retry_loop++) {
-		/* Wait for bootloader to signify that is
-		    ready having bit 31 of C2PMSG_35 set to 1 */
-		ret = psp_wait_for(psp,
-				   SOC15_REG_OFFSET(MP0, 0, regMP0_SMN_C2PMSG_35),
-				   0x80000000,
-				   0x80000000,
-				   false);
+		ret = psp_wait_for(
+			psp, SOC15_REG_OFFSET(MP0, 0, regMP0_SMN_C2PMSG_35),
+			0x80000000, 0xffffffff, false);
 
 		if (ret == 0)
 			return 0;
-- 
2.40.1