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scsi: ufs-mediatek: Do not gate clocks if auto-hibern8 is not entered yet 

There is a chance that link enters hibern8 via auto-hibern8 scheme during
the clock-gating flow. Clocks shall not be gated if link is still active
otherwise host or device may hang.

Fix this by returning error code to the caller __ufshcd_setup_clocks() to
skip gating clocks there if link is not confirmed in hibern8 state yet.

Also allow some waiting time for the hibern8 state transition.

Link: https://lore.kernel.org/r/20200601104646.15436-3-stanley.chu@mediatek.com
Reviewed-by: Andy Teng <andy.teng@mediatek.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Stanley Chu 2020-06-01 18:46:43 +08:00 committed by Martin K. Petersen
parent fb43337cd4
commit 9006e3986f
1 changed files with 27 additions and 9 deletions
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36
drivers/scsi/ufs/ufs-mediatek.c
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@ -178,15 +178,30 @@ static void ufs_mtk_setup_ref_clk_wait_us(struct ufs_hba *hba,
host->ref_clk_ungating_wait_us = ungating_us;
}
static u32 ufs_mtk_link_get_state(struct ufs_hba *hba)
int ufs_mtk_wait_link_state(struct ufs_hba *hba, u32 state,
unsigned long max_wait_ms)
{
ktime_t timeout, time_checked;
u32 val;
ufshcd_writel(hba, 0x20, REG_UFS_DEBUG_SEL);
val = ufshcd_readl(hba, REG_UFS_PROBE);
val = val >> 28;
timeout = ktime_add_us(ktime_get(), ms_to_ktime(max_wait_ms));
do {
time_checked = ktime_get();
ufshcd_writel(hba, 0x20, REG_UFS_DEBUG_SEL);
val = ufshcd_readl(hba, REG_UFS_PROBE);
val = val >> 28;
return val;
if (val == state)
return 0;
/* Sleep for max. 200us */
usleep_range(100, 200);
} while (ktime_before(time_checked, timeout));
if (val == state)
return 0;
return -ETIMEDOUT;
}
/**
@ -221,10 +236,13 @@ static int ufs_mtk_setup_clocks(struct ufs_hba *hba, bool on,
* triggered by Auto-Hibern8.
*/
if (!ufshcd_can_hibern8_during_gating(hba) &&
ufshcd_is_auto_hibern8_enabled(hba) &&
ufs_mtk_link_get_state(hba) ==
VS_LINK_HIBERN8)
ufs_mtk_setup_ref_clk(hba, on);
ufshcd_is_auto_hibern8_enabled(hba)) {
ret = ufs_mtk_wait_link_state(hba,
VS_LINK_HIBERN8,
15);
if (!ret)
ufs_mtk_setup_ref_clk(hba, on);
}
}
} else if (on && status == POST_CHANGE) {
ret = phy_power_on(host->mphy);