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Subject[PATCH v3 2/3] scsi: ufs: Use freq table with devfreq
Date
devfreq requires that the client operates on actual frequencies, not
only 0 and UMAX_INT and as such UFS brok with the introduction of
f1d981eaecf8 ("PM / devfreq: Use the available min/max frequency").

This patch registers the frequencies of the first clock with devfreq and
use these to determine if we're trying to step up or down.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> [for devfreq & OPP part]
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

Changes since v2:
- Picked up R-b from Chanwoo and Subhash

Chances since v1:
- Register min_freq and max_freq as opp levels.
- Unregister opp levels on removal, to make e.g. probe defer working

drivers/scsi/ufs/ufshcd.c | 47 +++++++++++++++++++++++++++++++++------
1 file changed, 40 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index f04902a066cb..3d46a70ed41d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1200,16 +1200,13 @@ static int ufshcd_devfreq_target(struct device *dev,
struct ufs_hba *hba = dev_get_drvdata(dev);
ktime_t start;
bool scale_up, sched_clk_scaling_suspend_work = false;
+ struct list_head *clk_list = &hba->clk_list_head;
+ struct ufs_clk_info *clki;
unsigned long irq_flags;

if (!ufshcd_is_clkscaling_supported(hba))
return -EINVAL;

- if ((*freq > 0) && (*freq < UINT_MAX)) {
- dev_err(hba->dev, "%s: invalid freq = %lu\n", __func__, *freq);
- return -EINVAL;
- }
-
spin_lock_irqsave(hba->host->host_lock, irq_flags);
if (ufshcd_eh_in_progress(hba)) {
spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
@@ -1219,7 +1216,13 @@ static int ufshcd_devfreq_target(struct device *dev,
if (!hba->clk_scaling.active_reqs)
sched_clk_scaling_suspend_work = true;

- scale_up = (*freq == UINT_MAX) ? true : false;
+ if (list_empty(clk_list)) {
+ spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
+ goto out;
+ }
+
+ clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
+ scale_up = (*freq == clki->max_freq) ? true : false;
if (!ufshcd_is_devfreq_scaling_required(hba, scale_up)) {
spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
ret = 0;
@@ -1289,16 +1292,29 @@ static struct devfreq_dev_profile ufs_devfreq_profile = {

static int ufshcd_devfreq_init(struct ufs_hba *hba)
{
+ struct list_head *clk_list = &hba->clk_list_head;
+ struct ufs_clk_info *clki;
struct devfreq *devfreq;
int ret;

- devfreq = devm_devfreq_add_device(hba->dev,
+ /* Skip devfreq if we don't have any clocks in the list */
+ if (list_empty(clk_list))
+ return 0;
+
+ clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+ dev_pm_opp_add(hba->dev, clki->min_freq, 0);
+ dev_pm_opp_add(hba->dev, clki->max_freq, 0);
+
+ devfreq = devfreq_add_device(hba->dev,
&ufs_devfreq_profile,
DEVFREQ_GOV_SIMPLE_ONDEMAND,
NULL);
if (IS_ERR(devfreq)) {
ret = PTR_ERR(devfreq);
dev_err(hba->dev, "Unable to register with devfreq %d\n", ret);
+
+ dev_pm_opp_remove(hba->dev, clki->min_freq);
+ dev_pm_opp_remove(hba->dev, clki->max_freq);
return ret;
}

@@ -1307,6 +1323,22 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
return 0;
}

+static void ufshcd_devfreq_remove(struct ufs_hba *hba)
+{
+ struct list_head *clk_list = &hba->clk_list_head;
+ struct ufs_clk_info *clki;
+
+ if (!hba->devfreq)
+ return;
+
+ devfreq_remove_device(hba->devfreq);
+ hba->devfreq = NULL;
+
+ clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+ dev_pm_opp_remove(hba->dev, clki->min_freq);
+ dev_pm_opp_remove(hba->dev, clki->max_freq);
+}
+
static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
{
unsigned long flags;
@@ -7005,6 +7037,7 @@ static void ufshcd_hba_exit(struct ufs_hba *hba)
if (hba->devfreq)
ufshcd_suspend_clkscaling(hba);
destroy_workqueue(hba->clk_scaling.workq);
+ ufshcd_devfreq_remove(hba);
}
ufshcd_setup_clocks(hba, false);
ufshcd_setup_hba_vreg(hba, false);
--
2.17.0
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