Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1258001

[PATCH v6 12/15] scsi: ufs: reduce the interrupts for power mode change requests

From Yaniv Gardi <ygardi@codeaurora.org>
Newsgroups linux.kernel
Subject [PATCH v6 12/15] scsi: ufs: reduce the interrupts for power mode change requests
Date 2015-10-28 14:20 +0100
Message-ID <qoyNZ-35R-39@gated-at.bofh.it> (permalink)
References <qoyNY-35R-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

DME commands such as Hibern8 enter/exit and gear switch generate 2
completion interrupts, one for confirmation that command is received
by local UniPro and 2nd one is the final confirmation after communication
with remote UniPro. Currently both of these completions are registered
as interrupt events which is not quite necessary and instead we can
just wait for the interrupt of 2nd completion, this should reduce
the number of interrupts and could reduce the unnecessary CPU wakeups
to handle extra interrupts.

Reviewed-by: Gilad Broner <gbroner@codeaurora.org>
Reviewed-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

---
 drivers/scsi/ufs/ufshcd.c | 41 +++++++++++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 889a7be..24a879d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -987,13 +987,15 @@ ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
  * __ufshcd_send_uic_cmd - Send UIC commands and retrieve the result
  * @hba: per adapter instance
  * @uic_cmd: UIC command
+ * @completion: initialize the completion only if this is set to true
  *
  * Identical to ufshcd_send_uic_cmd() expect mutex. Must be called
  * with mutex held and host_lock locked.
  * Returns 0 only if success.
  */
 static int
-__ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
+__ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd,
+		      bool completion)
 {
 	if (!ufshcd_ready_for_uic_cmd(hba)) {
 		dev_err(hba->dev,
@@ -1001,7 +1003,8 @@ __ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 		return -EIO;
 	}
 
-	init_completion(&uic_cmd->done);
+	if (completion)
+		init_completion(&uic_cmd->done);
 
 	ufshcd_dispatch_uic_cmd(hba, uic_cmd);
 
@@ -1026,7 +1029,7 @@ ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	ufshcd_add_delay_before_dme_cmd(hba);
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
-	ret = __ufshcd_send_uic_cmd(hba, uic_cmd);
+	ret = __ufshcd_send_uic_cmd(hba, uic_cmd, true);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	if (!ret)
 		ret = ufshcd_wait_for_uic_cmd(hba, uic_cmd);
@@ -2347,6 +2350,7 @@ 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);
 	init_completion(&uic_async_done);
@@ -2354,15 +2358,17 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->uic_async_done = &uic_async_done;
-	ret = __ufshcd_send_uic_cmd(hba, cmd);
-	spin_unlock_irqrestore(hba->host->host_lock, flags);
-	if (ret) {
-		dev_err(hba->dev,
-			"pwr ctrl cmd 0x%x with mode 0x%x uic error %d\n",
-			cmd->command, cmd->argument3, ret);
-		goto out;
+	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.
+		 */
+		wmb();
+		reenable_intr = true;
 	}
-	ret = ufshcd_wait_for_uic_cmd(hba, cmd);
+	ret = __ufshcd_send_uic_cmd(hba, cmd, false);
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	if (ret) {
 		dev_err(hba->dev,
 			"pwr ctrl cmd 0x%x with mode 0x%x uic error %d\n",
@@ -2388,7 +2394,10 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 	}
 out:
 	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);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	mutex_unlock(&hba->uic_cmd_mutex);
 
@@ -3813,16 +3822,20 @@ static void ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
  */
 static irqreturn_t ufshcd_intr(int irq, void *__hba)
 {
-	u32 intr_status;
+	u32 intr_status, enabled_intr_status;
 	irqreturn_t retval = IRQ_NONE;
 	struct ufs_hba *hba = __hba;
 
 	spin_lock(hba->host->host_lock);
 	intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
+	enabled_intr_status =
+		intr_status & ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
 
-	if (intr_status) {
+	if (intr_status)
 		ufshcd_writel(hba, intr_status, REG_INTERRUPT_STATUS);
-		ufshcd_sl_intr(hba, intr_status);
+
+	if (enabled_intr_status) {
+		ufshcd_sl_intr(hba, enabled_intr_status);
 		retval = IRQ_HANDLED;
 	}
 	spin_unlock(hba->host->host_lock);
-- 
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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v6 00/15] Big fixes, retries, handle a race condition Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 13/15] scsi: ufs: add missing memory barriers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 08/15] scsi: ufs: add retries to dme_peer get and set attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 12/15] scsi: ufs: reduce the interrupts for power mode change requests Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 04/15] scsi: ufs: clear outstanding_request bit in case query timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 01/15] scsi: ufs: clear UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 15/15] scsi: ufs: add wrapper for retrying sending query attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 11/15] scsi: ufs: retry failed query flag requests Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 14/15] scsi: ufs: commit descriptors before setting the doorbell Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 06/15] scsi: ufs: avoid exception event handler racing with PM callbacks Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  [PATCH v6 07/15] scsi: ufs: set REQUEST_SENSE command size to 18 bytes Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
    Re: [PATCH v6 07/15] scsi: ufs: set REQUEST_SENSE command size to 18  bytes Hannes Reinecke <hare@suse.de> - 2015-10-30 13:20 +0100
  [PATCH v6 03/15] scsi: ufs: verify command tag validity Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-28 14:20 +0100
  Re: [PATCH v6 00/15] Big fixes, retries, handle a race condition Hannes Reinecke <hare@suse.de> - 2015-10-30 13:30 +0100

csiph-web