[PATCH v2 04/17] scsi: ufs: avoid spurious UFS host controller interrupts
From: Yaniv Gardi
Date: Mon Oct 26 2015 - 11:41:51 EST
When control reaches to Linux UFS driver during UFS boot mode, UFS host
controller interrupt status/enable registers may have left over
settings.
In order to avoid any spurious interrupts due to these left overs,
it's important to clear these interrupt status/enable registers before
enabling UFS interrupt handling.
Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 00964f9..a0aac38 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5864,6 +5864,21 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
init_waitqueue_head(&hba->dev_cmd.tag_wq);
ufshcd_init_clk_gating(hba);
+
+ /*
+ * In order to avoid any spurious interrupt immediately after
+ * registering UFS controller interrupt handler, clear any pending UFS
+ * interrupt status and disable all the UFS interrupts.
+ */
+ ufshcd_writel(hba, ufshcd_readl(hba, REG_INTERRUPT_STATUS),
+ REG_INTERRUPT_STATUS);
+ ufshcd_writel(hba, 0, REG_INTERRUPT_ENABLE);
+ /*
+ * Make sure that UFS interrupts are disabled and any pending interrupt
+ * status is cleared before registering UFS interrupt handler.
+ */
+ mb();
+
/* IRQ registration */
err = devm_request_irq(dev, irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba);
if (err) {
--
1.8.5.2
--
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