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Message-ID: <5f511591d42f5022599fd53c81422a9e.squirrel@www.codeaurora.org>
Date: Tue, 27 Oct 2015 14:59:44 -0000
From: "Gilad Broner" <gbroner@...eaurora.org>
To: "Yaniv Gardi" <ygardi@...eaurora.org>
Cc: robherring2@...il.com, james.bottomley@...senpartnership.com,
pebolle@...cali.nl, hch@...radead.org,
linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
linux-arm-msm@...r.kernel.org, santoshsy@...il.com,
linux-scsi-owner@...r.kernel.org, subhashj@...eaurora.org,
ygardi@...eaurora.org, gbroner@...eaurora.org,
draviv@...eaurora.org,
"Vinayak Holikatti" <vinholikatti@...il.com>,
"James E.J. Bottomley" <jbottomley@...n.com>
Subject: Re: [PATCH v5 12/15] scsi: ufs: reduce the interrupts for power mode
change requests
Reviewed-by: Gilad Broner <gbroner@...eaurora.org>
> 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.
>
> Signed-off-by: Subhash Jadavani <subhashj@...eaurora.org>
> Signed-off-by: Yaniv Gardi <ygardi@...eaurora.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
>
> --
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> of Code Aurora Forum, hosted by The Linux Foundation
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