linux-kernel - [PATCH] gpu: drm: radeon: rs600: Replace mdelay() with msleep() and usleep_range() in rs600_asic

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Date:   Sat,  4 Aug 2018 08:05:52 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     alexander.deucher@....com, christian.koenig@....com,
        David1.Zhou@....com, airlied@...ux.ie
Cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] gpu: drm: radeon: rs600: Replace mdelay() with msleep() and usleep_range() in rs600_asic_reset()

rs600_asic_reset() is never called in atomic context.
They call mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep() and usleep_range().

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 drivers/gpu/drm/radeon/rs600.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/radeon/rs600.c b/drivers/gpu/drm/radeon/rs600.c
index f16af119c688..1a97f5fd719b 100644
--- a/drivers/gpu/drm/radeon/rs600.c
+++ b/drivers/gpu/drm/radeon/rs600.c
@@ -472,30 +472,30 @@ int rs600_asic_reset(struct radeon_device *rdev, bool hard)
 	pci_save_state(rdev->pdev);
 	/* disable bus mastering */
 	pci_clear_master(rdev->pdev);
-	mdelay(1);
+	usleep_range(1000, 2000);
 	/* reset GA+VAP */
 	WREG32(R_0000F0_RBBM_SOFT_RESET, S_0000F0_SOFT_RESET_VAP(1) |
 					S_0000F0_SOFT_RESET_GA(1));
 	RREG32(R_0000F0_RBBM_SOFT_RESET);
-	mdelay(500);
+	msleep(500);
 	WREG32(R_0000F0_RBBM_SOFT_RESET, 0);
-	mdelay(1);
+	usleep_range(1000, 2000);
 	status = RREG32(R_000E40_RBBM_STATUS);
 	dev_info(rdev->dev, "(%s:%d) RBBM_STATUS=0x%08X\n", __func__, __LINE__, status);
 	/* reset CP */
 	WREG32(R_0000F0_RBBM_SOFT_RESET, S_0000F0_SOFT_RESET_CP(1));
 	RREG32(R_0000F0_RBBM_SOFT_RESET);
-	mdelay(500);
+	msleep(500);
 	WREG32(R_0000F0_RBBM_SOFT_RESET, 0);
-	mdelay(1);
+	usleep_range(1000, 2000);
 	status = RREG32(R_000E40_RBBM_STATUS);
 	dev_info(rdev->dev, "(%s:%d) RBBM_STATUS=0x%08X\n", __func__, __LINE__, status);
 	/* reset MC */
 	WREG32(R_0000F0_RBBM_SOFT_RESET, S_0000F0_SOFT_RESET_MC(1));
 	RREG32(R_0000F0_RBBM_SOFT_RESET);
-	mdelay(500);
+	msleep(500);
 	WREG32(R_0000F0_RBBM_SOFT_RESET, 0);
-	mdelay(1);
+	usleep_range(1000, 2000);
 	status = RREG32(R_000E40_RBBM_STATUS);
 	dev_info(rdev->dev, "(%s:%d) RBBM_STATUS=0x%08X\n", __func__, __LINE__, status);
 	/* restore PCI & busmastering */
-- 
2.17.0