[PATCH V2 6/8] scsi: ufs: core: Set and clear UIC Completion interrupt as needed

[Adrian Hunter <adrian.hunter@intel.com>]

Currently the UIC Completion interrupt is left enabled except for when
issuing link hibernate commands, in which case the interrupt is disabled
and then re-enabled.

Instead, set and clear the interrupt enable bit as needed.

That is slightly simpler and less error prone, but also avoids side effects
of accessing the interrupt enable register after entering link hibernation.
Specifically, for some host controllers like Intel MTL, doing so disrupts
the link state transition.

Note also, the interrupt register is not read back anymore after it is
updated.  No other code does that, so it is assumed to be no longer
necessary if it ever was.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/ufs/core/ufshcd.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 7fb0ca3576d4..1567aba866b5 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -2622,6 +2622,7 @@ __ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
  */
 int ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 {
+	unsigned long flags;
 	int ret;
 
 	if (hba->quirks & UFSHCD_QUIRK_BROKEN_UIC_CMD)
@@ -2631,6 +2632,10 @@ int ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	mutex_lock(&hba->uic_cmd_mutex);
 	ufshcd_add_delay_before_dme_cmd(hba);
 
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+
 	ret = __ufshcd_send_uic_cmd(hba, uic_cmd);
 	if (!ret)
 		ret = ufshcd_wait_for_uic_cmd(hba, uic_cmd);
@@ -4318,7 +4323,6 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 	unsigned long flags;
 	u8 status;
 	int ret;
-	bool reenable_intr = false;
 
 	mutex_lock(&hba->uic_cmd_mutex);
 	ufshcd_add_delay_before_dme_cmd(hba);
@@ -4329,15 +4333,7 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 		goto out_unlock;
 	}
 	hba->uic_async_done = &uic_async_done;
-	if (ufshcd_readl(hba, REG_INTERRUPT_ENABLE) & UIC_COMMAND_COMPL) {
-		ufshcd_disable_intr(hba, UIC_COMMAND_COMPL);
-		/*
-		 * Make sure UIC command completion interrupt is disabled before
-		 * issuing UIC command.
-		 */
-		ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
-		reenable_intr = true;
-	}
+	ufshcd_disable_intr(hba, UIC_COMMAND_COMPL);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	ret = __ufshcd_send_uic_cmd(hba, cmd);
 	if (ret) {
@@ -4381,8 +4377,6 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->active_uic_cmd = NULL;
 	hba->uic_async_done = NULL;
-	if (reenable_intr)
-		ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
 	if (ret) {
 		ufshcd_set_link_broken(hba);
 		ufshcd_schedule_eh_work(hba);
-- 
2.48.1