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Subject[v4 02/14] scsi: ufs: avoid spurious UFS host controller interrupts
Date
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@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

---
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 65593b3..b0ef94d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5837,6 +5837,21 @@ 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
--
QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

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