On 4/26/2013 10:44 AM, Seungwon Jeon wrote:
On Thursday, April 25, 2013 , Sujit Reddy Thumma wrote:
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?
I completed to check your patch to compare it now.
Though it's just my thought, the patch I sent is more intuitive on the whole.
Considering other dme operations which I have introduced, it looks like matched.
There are lot of code duplications you might want to minimize building a
DME command.
Of course, you may disagree.
But I think the part of mutex is needed. It's a good point.
In case of error handling, I didn't catch nothing special.
Rather, handling link lost case is not proper.
When ufs host meets link lost status, it should start with dme_reset not retried dme_linkstartup.
In section 7.2.1 (Host Controller Initialization) of JESD223A UFS HCI
v1.1 specification I find this -
6. Sent DME_LINKSTARTUP command to start the link startup procedure
9. Check value of HCS.DP and make sure that there is a device attached
to the Link. If presence of a device is detected, go to step 10;
otherwise, resend the DME_LINKSTARTUP command after IS.ULLS has been set
to 1 (Go to step 6). IS.ULLS equal 1 indicates that the UFS Device is
ready for a link startup.
Going by the spec. just retrying with DME_LINKSTARTUP is correct.
In addition, it doesn't say what happens if IS.ULLS never sets to 1.
Probably, the case which never happens.
And it would be good if link start-up procedure is done in separate process, not in driver probe.
True.
If it's all right with you, I'd like to update lock mechanism for uic command.
I can add your signed-off. Please let me know your opinion.
I would like to get a third opinion as both the patches needs modifications.
Some comments below:
Signed-off-by: Seungwon Jeon <tgih.jun@xxxxxxxxxxx>
---
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);
Error code is incorrect. only -ETIMEDOUT is valid others are just DME
errors.
Also, spec. clearly mentions a retry mechanism which means that there
could be some timing issues anticipated where the UIC layer cannot
respond properly.
+ 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);
The recovery when UIC_ERROR happens is broken because of re-entrancy to
dme_link_startup from ufshcd_fatal_err_handler(). So better handle with
timeout than allowing controller to raise a UIC_ERROR until that is fixed?
+
/* 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)
why this redundant check if it is already checked in ufshcd_sl_intr()?
+ 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);
Can we use async function calls kernel/async.c instead of having work
queues as this is only used during boot up?
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
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