scsi: ufs: disable irq before disabling clocks

During suspend flow, interrupt shall be disabled before disabling clocks to
avoid potential system hang due to accessing host registers after host
clocks are disabled.

For example, if an interrupt comes with IRQF_IRQPOLL flag configured with
the misrouted interrupt recovery feature enabled, ufshcd ISR may be
triggered even if nothing shall be done for UFS. In this case, system hang
may happen if UFS interrupt status register is accessed with host clocks
disabled.

Link: https://lore.kernel.org/r/1575721321-8071-2-git-send-email-stanley.chu@mediatek.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c299c5f..f55cf03 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7890,6 +7890,11 @@ disable_clks:
        ret = ufshcd_vops_suspend(hba, pm_op);
        if (ret)
                goto set_link_active;
+       /*
+        * Disable the host irq as host controller as there won't be any
+        * host controller transaction expected till resume.
+        */
+       ufshcd_disable_irq(hba);
 
        if (!ufshcd_is_link_active(hba))
                ufshcd_setup_clocks(hba, false);
@@ -7899,11 +7904,7 @@ disable_clks:
 
        hba->clk_gating.state = CLKS_OFF;
        trace_ufshcd_clk_gating(dev_name(hba->dev), hba->clk_gating.state);
-       /*
-        * Disable the host irq as host controller as there won't be any
-        * host controller transaction expected till resume.
-        */
-       ufshcd_disable_irq(hba);
+
        /* Put the host controller in low power mode if possible */
        ufshcd_hba_vreg_set_lpm(hba);
        goto out;