diff mbox series

[v3] ufs: poll pmc until another pa request is completed

Message ID 1684209152-115304-1-git-send-email-kwmad.kim@samsung.com
State Superseded
Headers show
Series [v3] ufs: poll pmc until another pa request is completed | expand

Commit Message

Kiwoong Kim May 16, 2023, 3:52 a.m. UTC
v2 -> v3
1) check time in the loop with jiffies, instead of miliseconds.
2) change a variable's name and fix a typo and wrong alignment.

v1 -> v2
1) remove clearing hba->active_uic_cmd at the end of __ufshcd_poll_uic_pwr
2) change commit message on the cited clause: 5.7.12.11 -> 5.7.12.1.1
3) add mdelay to avoid too many issueing
4) change the timeout for the polling to 100ms because I found it
sometimes takes much longer than expected.

Regarding 5.7.12.1.1 in Unipro v1.8, PA rejects sebsequent
requests following the first request from upper layer or remote.
In this situation, PA responds w/ BUSY in cases
when they come from upper layer and does nothing for
the requests. So HCI doesn't receive ind, a.k.a. indicator
for its requests and an interrupt, IS.UPMS isn't generated.

When LINERESET occurs, the error handler issues PMC which is
recognized as a request for PA. If a host's PA gets or raises
LINERESET, and a request for PMC, this could be a concurrent
situation mentioned above. And I found that situation w/ my
environment.

[  222.929539]I[0:DefaultDispatch:20410] exynos-ufs 13500000.ufs: ufshcd_update_uic_error: uecdl : 0x80000002
[  222.999009]I[0: arch_disk_io_1:20413] exynos-ufs 13500000.ufs: ufshcd_update_uic_error: uecpa : 0x80000010
[  222.999200] [6:  kworker/u16:2:  132] exynos-ufs 13500000.ufs: ufs_pwr_mode_restore_needed : mode = 0x15, pwr_rx = 1, pwr_tx = 1
[  223.002876]I[0: arch_disk_io_3:20422] exynos-ufs 13500000.ufs: ufshcd_update_uic_error: uecpa : 0x80000010
[  223.501050] [4:  kworker/u16:2:  132] exynos-ufs 13500000.ufs: pwr ctrl cmd 0x2 with mode 0x11 completion timeout
[  223.502305] [4:  kworker/u16:2:  132] exynos-ufs 13500000.ufs: ufshcd_change_power_mode: power mode change failed -110
[  223.502312] [4:  kworker/u16:2:  132] exynos-ufs 13500000.ufs: ufshcd_err_handler: Failed to restore power mode, err = -110
[  223.502392] [4:  kworker/u16:2:  132] exynos-ufs 13500000.ufs: ufshcd_is_pwr_mode_restore_needed : mode = 0x11, pwr_rx = 1, pwr_tx = 1

This patch is to poll PMC's result w/o checking its ind until
the result is not busy, i.e. 09h, to avoid the rejection.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/ufs/core/ufshcd.c | 89 ++++++++++++++++++++++++++++++++++-------------
 1 file changed, 64 insertions(+), 25 deletions(-)

Comments

Bart Van Assche May 19, 2023, 10:20 p.m. UTC | #1
On 5/15/23 20:52, Kiwoong Kim wrote:
> +		spin_lock_irqsave(hba->host->host_lock, flags);
> +		hba->active_uic_cmd = NULL;
> +		if (ufshcd_is_link_broken(hba)) {
> +			spin_unlock_irqrestore(hba->host->host_lock, flags);
> +			ret = -ENOLINK;
> +			goto out;
> +		}
> +		hba->uic_async_done = cnf;
> +		cmd->argument2 = 0;
> +		cmd->argument3 = mode;
> +		ret = __ufshcd_send_uic_cmd(hba, cmd, true);
> +		spin_unlock_irqrestore(hba->host->host_lock, flags);

Please consider adding 	lockdep_assert_held(&hba->uic_cmd_mutex) near
the start of __ufshcd_poll_uic_pwr() to document that this function is
serialized against other contexts that submit an UIC.

Additionally, I don't think that it is necessary to hold the host lock
around the ufshcd_is_link_broken() or __ufshcd_send_uic_cmd() calls.

Thanks,

Bart.
Kiwoong Kim May 22, 2023, 1:58 a.m. UTC | #2
> > +		spin_lock_irqsave(hba->host->host_lock, flags);
> > +		hba->active_uic_cmd = NULL;
> > +		if (ufshcd_is_link_broken(hba)) {
> > +			spin_unlock_irqrestore(hba->host->host_lock, flags);
> > +			ret = -ENOLINK;
> > +			goto out;
> > +		}
> > +		hba->uic_async_done = cnf;
> > +		cmd->argument2 = 0;
> > +		cmd->argument3 = mode;
> > +		ret = __ufshcd_send_uic_cmd(hba, cmd, true);
> > +		spin_unlock_irqrestore(hba->host->host_lock, flags);
> 
> Please consider adding 	lockdep_assert_held(&hba->uic_cmd_mutex) near
> the start of __ufshcd_poll_uic_pwr() to document that this function is
> serialized against other contexts that submit an UIC.

Got it.

> 
> Additionally, I don't think that it is necessary to hold the host lock
> around the ufshcd_is_link_broken() or __ufshcd_send_uic_cmd() calls.

I agree with you on __ufshcd_send_uic_cmd because of the mutex. And I wonder why you make you think that on uic_link_state.
Is it because you think it's not possible to access uic_link_state simultaneously w/ the current code or it should be?

It seems most cases have no problems but anyway I think it seems that uic_link_state could be accessed from more than one context,
especially if auto hibern8 is enabled and only if some UIC errors occur.


Thanks.
Kiwoong Kim
> 
> Thanks,
> 
> Bart.
>
diff mbox series

Patch

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 9434328..2359367 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -98,6 +98,9 @@ 
 /* Polling time to wait for fDeviceInit */
 #define FDEVICEINIT_COMPL_TIMEOUT 1500 /* millisecs */
 
+/* Polling time to wait until PA is ready */
+#define UIC_PA_RDY_TIMEOUT	100	/* millisecs */
+
 /* UFSHC 4.0 compliant HC support this mode, refer param_set_mcq_mode() */
 static bool use_mcq_mode = true;
 
@@ -4138,6 +4141,61 @@  int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 }
 EXPORT_SYMBOL_GPL(ufshcd_dme_get_attr);
 
+static int __ufshcd_poll_uic_pwr(struct ufs_hba *hba, struct uic_command *cmd,
+		struct completion *cnf)
+{
+	unsigned long flags;
+	int ret;
+	u32 mode = cmd->argument3;
+	unsigned long deadline = jiffies +
+		msecs_to_jiffies(UIC_PA_RDY_TIMEOUT);
+
+	do {
+		spin_lock_irqsave(hba->host->host_lock, flags);
+		hba->active_uic_cmd = NULL;
+		if (ufshcd_is_link_broken(hba)) {
+			spin_unlock_irqrestore(hba->host->host_lock, flags);
+			ret = -ENOLINK;
+			goto out;
+		}
+		hba->uic_async_done = cnf;
+		cmd->argument2 = 0;
+		cmd->argument3 = mode;
+		ret = __ufshcd_send_uic_cmd(hba, cmd, true);
+		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;
+		}
+
+		/* This value is heuristic */
+		if (!wait_for_completion_timeout(&cmd->done,
+						 msecs_to_jiffies(5))) {
+			ret = -ETIMEDOUT;
+			dev_err(hba->dev,
+				"pwr ctrl cmd 0x%x with mode 0x%x timeout\n",
+				cmd->command, cmd->argument3);
+			if (cmd->cmd_active)
+				goto out;
+
+			dev_info(hba->dev, "%s: pwr ctrl cmd has already been completed\n", __func__);
+		}
+
+		/* retry only for busy cases */
+		ret = cmd->argument2 & MASK_UIC_COMMAND_RESULT;
+		if (ret != UIC_CMD_RESULT_BUSY)
+			break;
+
+		dev_info(hba->dev, "%s: PA is busy and can't handle a requeest, %d\n", __func__, ret);
+		mdelay(1);
+
+	} while (time_before(jiffies, deadline));
+out:
+	return ret;
+}
+
 /**
  * ufshcd_uic_pwr_ctrl - executes UIC commands (which affects the link power
  * state) and waits for it to take effect.
@@ -4160,33 +4218,16 @@  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);
 
-	spin_lock_irqsave(hba->host->host_lock, flags);
-	if (ufshcd_is_link_broken(hba)) {
-		ret = -ENOLINK;
-		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.
-		 */
-		wmb();
-		reenable_intr = true;
-	}
-	ret = __ufshcd_send_uic_cmd(hba, cmd, false);
-	spin_unlock_irqrestore(hba->host->host_lock, flags);
+	ret = __ufshcd_poll_uic_pwr(hba, cmd, &uic_async_done);
 	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 (ret == -ENOLINK)
+			goto out_unlock;
+		else
+			goto out;
 	}
 
 	if (!wait_for_completion_timeout(hba->uic_async_done,
@@ -4223,14 +4264,12 @@  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);
 	}
-out_unlock:
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
+out_unlock:
 	mutex_unlock(&hba->uic_cmd_mutex);
 
 	return ret;