Re: [PATCH 4/5] scsi: ufs: rework link start-up process

Sujit Reddy Thumma
2013-04-25T05:05:07Z

On 4/24/2013 9:36 PM, Seungwon Jeon wrote:
> Link start-up requires long time with multiphase handshakes
> between UFS host and device. This affects driver's probe time.
> This patch let link start-up run asynchronously.
> And completion time of uic command is defined to avoid a
> permanent wait.

I have similar patch posted few days back "scsi: ufs: Generalize UFS
Interconnect Layer (UIC) command support" which does a bit more (mutex,
error handling) than what is done here. Can that be used/improved?

>
> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
> ---
> drivers/scsi/ufs/ufshcd.c | 114 +++++++++++++++++++++++++++++++++-----------
> drivers/scsi/ufs/ufshcd.h | 6 ++-
> 2 files changed, 89 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index efe2256..76ff332 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -38,6 +38,7 @@
> #define UFSHCD_ENABLE_INTRS (UTP_TRANSFER_REQ_COMPL |\
> UTP_TASK_REQ_COMPL |\
> UFSHCD_ERROR_MASK)
> +#define UIC_CMD_TIMEOUT 100
>
> enum {
> UFSHCD_MAX_CHANNEL = 0,
> @@ -357,13 +358,15 @@ static inline void ufshcd_hba_capabilities(struct ufs_hba *hba)
> }
>
> /**
> - * ufshcd_send_uic_command - Send UIC commands to unipro layers
> + * ufshcd_dispatch_uic_cmd - Dispatch UIC commands to unipro layers
> * @hba: per adapter instance
> * @uic_command: UIC command
> */
> static inline void
> -ufshcd_send_uic_command(struct ufs_hba *hba, struct uic_command *uic_cmnd)
> +ufshcd_dispatch_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmnd)
> {
> + init_completion(&uic_cmnd->done);
> +
> /* Write Args */
> ufshcd_writel(hba, REG_UIC_COMMAND_ARG_1, uic_cmnd->argument1);
> ufshcd_writel(hba, REG_UIC_COMMAND_ARG_2, uic_cmnd->argument2);
> @@ -375,6 +378,45 @@ ufshcd_send_uic_command(struct ufs_hba *hba, struct uic_command *uic_cmnd)
> }
>
> /**
> + * ufshcd_wait_for_uic_cmd - Wait complectioin of UIC command
> + * @hba: per adapter instance
> + * @uic_command: UIC command
> + *
> + * Returns 0 only if success.
> + */
> +static int ufshcd_wait_for_uic_cmd(struct ufs_hba *hba)
> +{
> + struct uic_command *uic_cmd = &hba->active_uic_cmd;
> + int ret;
> +
> + if (wait_for_completion_timeout(&uic_cmd->done,
> + msecs_to_jiffies(UIC_CMD_TIMEOUT)))
> + ret = ufshcd_get_uic_cmd_result(hba);
> + else
> + ret = -ETIMEDOUT;
> +
> + return ret;
> +}
> +
> +/**
> + * ufshcd_ready_uic_cmd - Check if controller is ready
> + * to accept UIC commands
> + * @hba: per adapter instance
> + * Return true on success, else false
> + */
> +static inline bool ufshcd_ready_uic_cmd(struct ufs_hba *hba)
> +{
> + if (ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY) {
> + return true;
> + } else {
> + dev_err(hba->dev,
> + "Controller not ready"
> + " to accept UIC commands\n");
> + return false;
> + }
> +}
> +
> +/**
> * ufshcd_map_sg - Map scatter-gather list to prdt
> * @lrbp - pointer to local reference block
> *
> @@ -735,15 +777,10 @@ static int ufshcd_dme_link_startup(struct ufs_hba *hba)
> {
> struct uic_command *uic_cmd;
> unsigned long flags;
> + int ret;
>
> - /* check if controller is ready to accept UIC commands */
> - if (((ufshcd_readl(hba, REG_CONTROLLER_STATUS)) &
> - UIC_COMMAND_READY) == 0x0) {
> - dev_err(hba->dev,
> - "Controller not ready"
> - " to accept UIC commands\n");
> + if (!ufshcd_ready_uic_cmd(hba))
> return -EIO;
> - }
>
> spin_lock_irqsave(hba->host->host_lock, flags);
>
> @@ -754,13 +791,16 @@ static int ufshcd_dme_link_startup(struct ufs_hba *hba)
> uic_cmd->argument2 = 0;
> uic_cmd->argument3 = 0;
>
> - /* enable UIC related interrupts */
> - ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
> + /* Dispatching UIC commands to controller */
> + ufshcd_dispatch_uic_cmd(hba, uic_cmd);
>
> - /* sending UIC commands to controller */
> - ufshcd_send_uic_command(hba, uic_cmd);
> spin_unlock_irqrestore(hba->host->host_lock, flags);
> - return 0;
> +
> + ret = ufshcd_wait_for_uic_cmd(hba);
> + if (ret)
> + dev_err(hba->dev, "link startup: error code %d returned\n", ret);
> +
> + return ret;
> }
>
> /**
> @@ -898,6 +938,9 @@ static int ufshcd_initialize_hba(struct ufs_hba *hba)
> if (ufshcd_hba_enable(hba))
> return -EIO;
>
> + /* enable UIC related interrupts */
> + ufshcd_enable_intr(hba, UIC_COMMAND_COMPL | UIC_ERROR);
> +
> /* Configure UTRL and UTMRL base address registers */
> ufshcd_writel(hba, REG_UTP_TRANSFER_REQ_LIST_BASE_L,
> lower_32_bits(hba->utrdl_dma_addr));
> @@ -909,7 +952,9 @@ static int ufshcd_initialize_hba(struct ufs_hba *hba)
> upper_32_bits(hba->utmrdl_dma_addr));
>
> /* Initialize unipro link startup procedure */
> - return ufshcd_dme_link_startup(hba);
> + schedule_work(&hba->link_startup_wq);
> +
> + return 0;
> }
>
> /**
> @@ -1186,6 +1231,16 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
> }
>
> /**
> + * ufshcd_uic_cmd_compl - handle completion of uic command
> + * @hba: per adapter instance
> + */
> +static void ufshcd_uic_cmd_compl(struct ufs_hba *hba, u32 intr_status)
> +{
> + if (intr_status & UIC_COMMAND_COMPL)
> + complete(&hba->active_uic_cmd.done);
> +}
> +
> +/**
> * ufshcd_transfer_req_compl - handle SCSI and query command completion
> * @hba: per adapter instance
> */
> @@ -1225,25 +1280,26 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
> }
>
> /**
> - * ufshcd_uic_cc_handler - handle UIC command completion
> + * ufshcd_link_startup - link initialization
> * @work: pointer to a work queue structure
> - *
> - * Returns 0 on success, non-zero value on failure
> */
> -static void ufshcd_uic_cc_handler (struct work_struct *work)
> +static void ufshcd_link_startup(struct work_struct *work)
> {
> struct ufs_hba *hba;
> + int ret;
>
> - hba = container_of(work, struct ufs_hba, uic_workq);
> + hba = container_of(work, struct ufs_hba, link_startup_wq);
>
> - if ((hba->active_uic_cmd.command == UIC_CMD_DME_LINK_STARTUP) &&
> - !(ufshcd_get_uic_cmd_result(hba))) {
> + ret = ufshcd_dme_link_startup(hba);
> + if (ret)
> + goto out;
>
> - if (ufshcd_make_hba_operational(hba))
> - dev_err(hba->dev,
> - "cc: hba not operational state\n");
> - return;
> - }
> + ret = ufshcd_make_hba_operational(hba);
> + if (ret)
> + goto out;
> + return;
> +out:
> + dev_err(hba->dev, "link startup failed %d\n", ret);
> }
>
> /**
> @@ -1307,7 +1363,7 @@ static void ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
> ufshcd_err_handler(hba);
>
> if (intr_status & UIC_COMMAND_COMPL)
> - schedule_work(&hba->uic_workq);
> + ufshcd_uic_cmd_compl(hba, intr_status);
>
> if (intr_status & UTP_TASK_REQ_COMPL)
> ufshcd_tmc_handler(hba);
> @@ -1694,7 +1750,7 @@ int ufshcd_init(struct device *dev, struct ufs_hba **hba_handle,
> init_waitqueue_head(&hba->ufshcd_tm_wait_queue);
>
> /* Initialize work queues */
> - INIT_WORK(&hba->uic_workq, ufshcd_uic_cc_handler);
> + INIT_WORK(&hba->link_startup_wq, ufshcd_link_startup);
> INIT_WORK(&hba->feh_workq, ufshcd_fatal_err_handler);
>
> /* IRQ registration */
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 87d5a94..2fb4d94 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -51,6 +51,7 @@
> #include <linux/bitops.h>
> #include <linux/pm_runtime.h>
> #include <linux/clk.h>
> +#include <linux/completion.h>
>
> #include <asm/irq.h>
> #include <asm/byteorder.h>
> @@ -83,6 +84,7 @@ struct uic_command {
> u32 argument3;
> int cmd_active;
> int result;
> + struct completion done;
> };
>
> /**
> @@ -140,7 +142,7 @@ struct ufshcd_lrb {
> * @tm_condition: condition variable for task management
> * @ufshcd_state: UFSHCD states
> * @intr_mask: Interrupt Mask Bits
> - * @uic_workq: Work queue for UIC completion handling
> + * @link_startup_wq: Work queue for link start-up
> * @feh_workq: Work queue for fatal controller error handling
> * @errors: HBA errors
> */
> @@ -179,7 +181,7 @@ struct ufs_hba {
> u32 intr_mask;
>
> /* Work Queues */
> - struct work_struct uic_workq;
> + struct work_struct link_startup_wq;
> struct work_struct feh_workq;
>
> /* HBA Errors */
>

--
Regards,
Sujit