Re: [PATCH 3/3] scsi: ufs: Use freq table with devfreq

From: Subhash Jadavani
Date: Tue Apr 24 2018 - 18:09:00 EST


On 2018-04-23 17:20, Bjorn Andersson wrote:
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.

Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 39 ++++++++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2253f24309ec..07b1f3c7bd2d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1168,16 +1168,13 @@ 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);
@@ -1187,7 +1184,13 @@ 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;
@@ -1257,11 +1260,33 @@ static struct devfreq_dev_profile
ufs_devfreq_profile = {

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

+ /* Skip devfreq if we don't have any clocks in the list */
+ if (list_empty(clk_list))
+ return 0;
+
+ profile = devm_kmemdup(hba->dev, &ufs_devfreq_profile,
+ sizeof(ufs_devfreq_profile), GFP_KERNEL);
+ if (!profile)
+ return -ENOMEM;
+
+ profile->max_state = 2;
+ profile->freq_table = devm_kcalloc(hba->dev, profile->max_state,
+ sizeof(unsigned long), GFP_KERNEL);
+ if (!profile->freq_table)
+ return -ENOMEM;
+
+ clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
+ profile->freq_table[0] = clki->min_freq;
+ profile->freq_table[1] = clki->max_freq;
+
devfreq = devm_devfreq_add_device(hba->dev,
- &ufs_devfreq_profile,
+ profile,
"simple_ondemand",
NULL);
if (IS_ERR(devfreq)) {

Looks good to me.
Reviewed-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>

--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project