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scsi: ufs: Add sysfs node to dynamically control clock gating 

Provide an option to enable/disable clock gating during runtime.
Write 1 or 0 to "clkgate_enable" sysfs node to enable/disable
clock gating.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
hifive-unleashed-5.1
Sahitya Tummala 2016-12-22 18:40:39 -08:00 committed by Martin K. Petersen
parent e7d38257a4
commit b427411abb
2 changed files with 51 additions and 1 deletions
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48
drivers/scsi/ufs/ufshcd.c
View File

@ -970,6 +970,41 @@ static ssize_t ufshcd_clkgate_delay_store(struct device *dev,
return count;
}
static ssize_t ufshcd_clkgate_enable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct ufs_hba *hba = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", hba->clk_gating.is_enabled);
}
static ssize_t ufshcd_clkgate_enable_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct ufs_hba *hba = dev_get_drvdata(dev);
unsigned long flags;
u32 value;
if (kstrtou32(buf, 0, &value))
return -EINVAL;
value = !!value;
if (value == hba->clk_gating.is_enabled)
goto out;
if (value) {
ufshcd_release(hba);
} else {
spin_lock_irqsave(hba->host->host_lock, flags);
hba->clk_gating.active_reqs++;
spin_unlock_irqrestore(hba->host->host_lock, flags);
}
hba->clk_gating.is_enabled = value;
out:
return count;
}
static void ufshcd_init_clk_gating(struct ufs_hba *hba)
{
if (!ufshcd_is_clkgating_allowed(hba))
@ -979,13 +1014,23 @@ static void ufshcd_init_clk_gating(struct ufs_hba *hba)
INIT_DELAYED_WORK(&hba->clk_gating.gate_work, ufshcd_gate_work);
INIT_WORK(&hba->clk_gating.ungate_work, ufshcd_ungate_work);
hba->clk_gating.is_enabled = true;
hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show;
hba->clk_gating.delay_attr.store = ufshcd_clkgate_delay_store;
sysfs_attr_init(&hba->clk_gating.delay_attr.attr);
hba->clk_gating.delay_attr.attr.name = "clkgate_delay_ms";
hba->clk_gating.delay_attr.attr.mode = S_IRUGO | S_IWUSR;
hba->clk_gating.delay_attr.attr.mode = 0644;
if (device_create_file(hba->dev, &hba->clk_gating.delay_attr))
dev_err(hba->dev, "Failed to create sysfs for clkgate_delay\n");
hba->clk_gating.enable_attr.show = ufshcd_clkgate_enable_show;
hba->clk_gating.enable_attr.store = ufshcd_clkgate_enable_store;
sysfs_attr_init(&hba->clk_gating.enable_attr.attr);
hba->clk_gating.enable_attr.attr.name = "clkgate_enable";
hba->clk_gating.enable_attr.attr.mode = 0644;
if (device_create_file(hba->dev, &hba->clk_gating.enable_attr))
dev_err(hba->dev, "Failed to create sysfs for clkgate_enable\n");
}
static void ufshcd_exit_clk_gating(struct ufs_hba *hba)
@ -993,6 +1038,7 @@ static void ufshcd_exit_clk_gating(struct ufs_hba *hba)
if (!ufshcd_is_clkgating_allowed(hba))
return;
device_remove_file(hba->dev, &hba->clk_gating.delay_attr);
device_remove_file(hba->dev, &hba->clk_gating.enable_attr);
cancel_work_sync(&hba->clk_gating.ungate_work);
cancel_delayed_work_sync(&hba->clk_gating.gate_work);
}

4
drivers/scsi/ufs/ufshcd.h
View File

@ -320,6 +320,8 @@ enum clk_gating_state {
* @is_suspended: clk gating is suspended when set to 1 which can be used
* during suspend/resume
* @delay_attr: sysfs attribute to control delay_attr
* @enable_attr: sysfs attribute to enable/disable clock gating
* @is_enabled: Indicates the current status of clock gating
* @active_reqs: number of requests that are pending and should be waited for
* completion before gating clocks.
*/
@ -330,6 +332,8 @@ struct ufs_clk_gating {
unsigned long delay_ms;
bool is_suspended;
struct device_attribute delay_attr;
struct device_attribute enable_attr;
bool is_enabled;
int active_reqs;
};