[PATCH RFC 4/7] mmc: core: add support for devfreq suspend/resume

Sayali Lokhande
2018-07-13T09:54:00Z

This change adds support for devfreq suspend/resume
to be called on each system suspend/resume, runtime
suspend/resume, power restore.

Signed-off-by: Talel Shenhar <tatias@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
---
drivers/mmc/core/core.c | 112 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/core.h | 2 +
drivers/mmc/core/host.c | 8 +++-
drivers/mmc/core/mmc.c | 27 ++++++++++++
drivers/mmc/core/sd.c | 13 ++++++
5 files changed, 160 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 0eaee42..49103cf 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -618,6 +618,111 @@ int mmc_init_clk_scaling(struct mmc_host *host)
EXPORT_SYMBOL(mmc_init_clk_scaling);

/**
+ * mmc_suspend_clk_scaling() - suspend clock scaling
+ * @host: pointer to mmc host structure
+ *
+ * This API will suspend devfreq feature for the specific host.
+ * The statistics collected by mmc will be cleared.
+ * This function is intended to be called by the pm callbacks
+ * (e.g. runtime_suspend, suspend) of the mmc device
+ */
+int mmc_suspend_clk_scaling(struct mmc_host *host)
+{
+ int err;
+
+ if (!host) {
+ WARN(1, "bad host parameter\n");
+ return -EINVAL;
+ }
+
+ if (!mmc_can_scale_clk(host) || !host->clk_scaling.enable)
+ return 0;
+
+ if (!host->clk_scaling.devfreq) {
+ pr_err("%s: %s: no devfreq is assosiated with this device\n",
+ mmc_hostname(host), __func__);
+ return -EPERM;
+ }
+
+ atomic_inc(&host->clk_scaling.devfreq_abort);
+ wake_up(&host->wq);
+ err = devfreq_suspend_device(host->clk_scaling.devfreq);
+ if (err) {
+ pr_err("%s: %s: failed to suspend devfreq\n",
+ mmc_hostname(host), __func__);
+ return err;
+ }
+ host->clk_scaling.enable = false;
+
+ host->clk_scaling.total_busy_time_us = 0;
+
+ pr_debug("%s: devfreq was removed\n", mmc_hostname(host));
+
+ return 0;
+}
+EXPORT_SYMBOL(mmc_suspend_clk_scaling);
+
+/**
+ * mmc_resume_clk_scaling() - resume clock scaling
+ * @host: pointer to mmc host structure
+ *
+ * This API will resume devfreq feature for the specific host.
+ * This API is intended to be called by the pm callbacks
+ * (e.g. runtime_suspend, suspend) of the mmc device
+ */
+int mmc_resume_clk_scaling(struct mmc_host *host)
+{
+ int err = 0;
+ u32 max_clk_idx = 0;
+ u32 devfreq_max_clk = 0;
+ u32 devfreq_min_clk = 0;
+
+ if (!host) {
+ WARN(1, "bad host parameter\n");
+ return -EINVAL;
+ }
+
+ if (!mmc_can_scale_clk(host))
+ return 0;
+
+ /*
+ * If clock scaling is already exited when resume is called, like
+ * during mmc shutdown, it is not an error and should not fail the
+ * API calling this.
+ */
+ if (!host->clk_scaling.devfreq) {
+ pr_warn("%s: %s: no devfreq is assosiated with this device\n",
+ mmc_hostname(host), __func__);
+ return 0;
+ }
+
+ atomic_set(&host->clk_scaling.devfreq_abort, 0);
+
+ max_clk_idx = host->clk_scaling.freq_table_sz - 1;
+ devfreq_max_clk = host->clk_scaling.freq_table[max_clk_idx];
+ devfreq_min_clk = host->clk_scaling.freq_table[0];
+
+ host->clk_scaling.curr_freq = devfreq_max_clk;
+ if (host->ios.clock < host->clk_scaling.freq_table[max_clk_idx])
+ host->clk_scaling.curr_freq = devfreq_min_clk;
+
+ host->clk_scaling.clk_scaling_in_progress = false;
+ host->clk_scaling.need_freq_change = false;
+
+ err = devfreq_resume_device(host->clk_scaling.devfreq);
+ if (err) {
+ pr_err("%s: %s: failed to resume devfreq (%d)\n",
+ mmc_hostname(host), __func__, err);
+ } else {
+ host->clk_scaling.enable = true;
+ pr_debug("%s: devfreq resumed\n", mmc_hostname(host));
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(mmc_resume_clk_scaling);
+
+/**
* mmc_exit_devfreq_clk_scaling() - Disable clock scaling
* @host: pointer to mmc host structure
*
@@ -642,6 +747,13 @@ int mmc_exit_clk_scaling(struct mmc_host *host)
return -EPERM;
}

+ err = mmc_suspend_clk_scaling(host);
+ if (err) {
+ pr_err("%s: %s: fail to suspend clock scaling (%d)\n",
+ mmc_hostname(host), __func__, err);
+ return err;
+ }
+
err = devfreq_remove_device(host->clk_scaling.devfreq);
if (err) {
pr_err("%s: remove devfreq failed (%d)\n",
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index fc0a9b7..249c20d 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -97,6 +97,8 @@ static inline void mmc_delay(unsigned int ms)
extern bool mmc_can_scale_clk(struct mmc_host *host);
extern int mmc_init_clk_scaling(struct mmc_host *host);
extern int mmc_exit_clk_scaling(struct mmc_host *host);
+extern int mmc_suspend_clk_scaling(struct mmc_host *host);
+extern int mmc_resume_clk_scaling(struct mmc_host *host);

int mmc_execute_tuning(struct mmc_card *card);
int mmc_hs200_to_hs400(struct mmc_card *card);
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 0504610..c3a71a5 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -442,15 +442,19 @@ static ssize_t store_enable(struct device *dev,
mmc_get_card(host->card, NULL);

if (!value) {
- /* mask host capability */
+ /* Suspend the clock scaling and mask host capability */
+ if (host->clk_scaling.enable)
+ mmc_suspend_clk_scaling(host);
host->caps2 &= ~MMC_CAP2_CLK_SCALE;
host->clk_scaling.state = MMC_LOAD_HIGH;
/* Set to max. frequency when disabling */
mmc_clk_update_freq(host, host->card->clk_scaling_highest,
host->clk_scaling.state);
} else if (value) {
- /* Unmask host capability*/
+ /* Unmask host capability and resume scaling */
host->caps2 |= MMC_CAP2_CLK_SCALE;
+ if (!host->clk_scaling.enable)
+ mmc_resume_clk_scaling(host);
}

mmc_put_card(host->card, NULL);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index c8aedf3..1d286af 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -2161,6 +2161,13 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
unsigned int notify_type = is_suspend ? EXT_CSD_POWER_OFF_SHORT :
EXT_CSD_POWER_OFF_LONG;

+ err = mmc_suspend_clk_scaling(host);
+ if (err) {
+ pr_err("%s: %s: fail to suspend clock scaling (%d)\n",
+ mmc_hostname(host), __func__, err);
+ return err;
+ }
+
mmc_claim_host(host);

if (mmc_card_suspended(host->card))
@@ -2190,6 +2197,8 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
}
out:
mmc_release_host(host);
+ if (err)
+ mmc_resume_clk_scaling(host);
return err;
}

@@ -2228,6 +2237,10 @@ static int _mmc_resume(struct mmc_host *host)

out:
mmc_release_host(host);
+ err = mmc_resume_clk_scaling(host);
+ if (err)
+ pr_err("%s: %s: fail to resume clock scaling (%d)\n",
+ mmc_hostname(host), __func__, err);
return err;
}

@@ -2335,6 +2348,15 @@ static int _mmc_hw_reset(struct mmc_host *host)
mmc_pwrseq_reset(host);
}

+ /* Suspend clk scaling to avoid switching frequencies intermittently */
+
+ ret = mmc_suspend_clk_scaling(host);
+ if (ret) {
+ pr_err("%s: %s: fail to suspend clock scaling (%d)\n",
+ mmc_hostname(host), __func__, ret);
+ return ret;
+ }
+
ret = mmc_init_card(host, card->ocr, card);
if (ret) {
pr_err("%s: %s: mmc_init_card failed (%d)\n",
@@ -2342,6 +2364,11 @@ static int _mmc_hw_reset(struct mmc_host *host)
return ret;
}

+ ret = mmc_resume_clk_scaling(host);
+ if (ret)
+ pr_err("%s: %s: fail to resume clock scaling (%d)\n",
+ mmc_hostname(host), __func__, ret);
+
return ret;
}

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 40144c1..5ae2916 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1131,6 +1131,13 @@ static int _mmc_sd_suspend(struct mmc_host *host)
{
int err = 0;

+ err = mmc_suspend_clk_scaling(host);
+ if (err) {
+ pr_err("%s: %s: fail to suspend clock scaling (%d)\n",
+ mmc_hostname(host), __func__, err);
+ return err;
+ }
+
mmc_claim_host(host);

if (mmc_card_suspended(host->card))
@@ -1182,6 +1189,12 @@ static int _mmc_sd_resume(struct mmc_host *host)
err = mmc_sd_init_card(host, host->card->ocr, host->card);
mmc_card_clr_suspended(host->card);

+ err = mmc_resume_clk_scaling(host);
+ if (err) {
+ pr_err("%s: %s: fail to resume clock scaling (%d)\n",
+ mmc_hostname(host), __func__, err);
+ goto out;
+ }
out:
mmc_release_host(host);
return err;