Re: [PATCH V2] wlcore: sdio: Fixup power on/off sequence

From: Ulf Hansson
Date: Mon Jan 21 2019 - 09:41:24 EST

On Fri, 18 Jan 2019 at 16:09, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>
> On Fri, 18 Jan 2019 at 13:09, Jan Kiszka <jan.kiszka@xxxxxx> wrote:
> >
> > On 17.01.19 10:54, Ulf Hansson wrote:
> > > On Wed, 16 Jan 2019 at 21:26, Jan Kiszka <jan.kiszka@xxxxxx> wrote:
> > >>
> > >> On 16.01.19 12:37, Ulf Hansson wrote:
> > >>> During "wlan-up", we are programming the FW into the WiFi-chip. However,
> > >>> re-programming the FW doesn't work, unless a power cycle of the WiFi-chip
> > >>> is made in-between the programmings.
> > >>>
> > >>> To conform to this requirement and to fix the regression in a simple way,
> > >>> let's start by allowing that the SDIO card (WiFi-chip) may stay powered on
> > >>> (runtime resumed) when wl12xx_sdio_power_off() returns. The intent with the
> > >>> current code is to treat this scenario as an error, but unfortunate this
> > >>> doesn't work as expected, so let's fix this.
> > >>>
> > >>> The other part is to guarantee that a power cycle of the SDIO card has been
> > >>> completed when wl12xx_sdio_power_on() returns, as to allow the FW
> > >>> programming to succeed. However, relying solely on runtime PM to deal with
> > >>> this isn't sufficient. For example, userspace may prevent runtime suspend
> > >>> via sysfs for the device that represents the SDIO card, leading to that the
> > >>> mmc core also keeps it powered on. For this reason, let's instead do a
> > >>> brute force power cycle in wl12xx_sdio_power_on().
> > >>>
> > >>> Fixes: 728a9dc61f13 ("wlcore: sdio: Fix flakey SDIO runtime PM handling")
> > >>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> > >>> ---
> > >>>
> > >>> Changes in v2:
> > >>> - Keep the SDIO host claimed when calling mmc_hw_reset().
> > >>> - Add a fixes tag.
> > >>> ---
> > >>> drivers/net/wireless/ti/wlcore/sdio.c | 15 +++++++--------
> > >>> 1 file changed, 7 insertions(+), 8 deletions(-)
> > >>>
> > >>> diff --git a/drivers/net/wireless/ti/wlcore/sdio.c b/drivers/net/wireless/ti/wlcore/sdio.c
> > >>> index bd10165d7eec..4d4b07701149 100644
> > >>> --- a/drivers/net/wireless/ti/wlcore/sdio.c
> > >>> +++ b/drivers/net/wireless/ti/wlcore/sdio.c
> > >>> @@ -164,6 +164,12 @@ static int wl12xx_sdio_power_on(struct wl12xx_sdio_glue *glue)
> > >>> }
> > >>>
> > >>> sdio_claim_host(func);
> > >>> + /*
> > >>> + * To guarantee that the SDIO card is power cycled, as required to make
> > >>> + * the FW programming to succeed, let's do a brute force HW reset.
> > >>> + */
> > >>> + mmc_hw_reset(card->host);
> > >>> +
> > >>> sdio_enable_func(func);
> > >>> sdio_release_host(func);
> > >>>
> > >>> @@ -174,20 +180,13 @@ static int wl12xx_sdio_power_off(struct wl12xx_sdio_glue *glue)
> > >>> {
> > >>> struct sdio_func *func = dev_to_sdio_func(glue->dev);
> > >>> struct mmc_card *card = func->card;
> > >>> - int error;
> > >>>
> > >>> sdio_claim_host(func);
> > >>> sdio_disable_func(func);
> > >>> sdio_release_host(func);
> > >>>
> > >>> /* Let runtime PM know the card is powered off */
> > >>> - error = pm_runtime_put(&card->dev);
> > >>> - if (error < 0 && error != -EBUSY) {
> > >>> - dev_err(&card->dev, "%s failed: %i\n", __func__, error);
> > >>> -
> > >>> - return error;
> > >>> - }
> > >>> -
> > >>> + pm_runtime_put(&card->dev);
> > >>> return 0;
> > >>> }
> > >>>
> > >>>
> > >>
> > >> Just tested on both HiKey (620) and Ultra96 but it fails to fix the issue on
> > >> both. I'm getting
> > >>
> > >> wl1271_sdio: probe of mmc2:0001:1 failed with error -16
> > >>
> > >> during boot again, and the interface is not available.
> > >
> > > Okay, sounds like this may be a different problem then. Can you share
> > > the complete log and the kernel config?
> >
> > You can find the config here [1], log from the HiKey boot attached.
> >
> > > I can prepare a debug patch as well, if you are willing to re-run the test?
> >
> > Sure, send it over, I can run it.
>
> Alright, sounds great. However, I need to defer that to Monday/Tuesday
> next week.
>
> >
> > >
> > > Adding a post-power-on-delay-ms of 1 ms as you suggested [1], doesn't
> > > sounds like the correct solution to me, unless I am overlooking some
> > > things. The point is, since the mmc core succeeds to detect and
> > > initialize the SDIO card, the power sequence seems to be correct.
> >
> > Yeah, I'm not claiming at all I know what I'm doing there, just that it happens
> > to work.
>
> I see. Good to know, thanks!
>
> >
> > Jan
> >
> > [1]
> > https://github.com/siemens/jailhouse-images/blob/next/recipes-kernel/linux/files/arm64_defconfig_4.19
>
> I have looked through the log and the defconfig. No obvious things
> found at this point. Thanks for sharing them!
>

So, I have put together a debug patch, mostly to verify that things
seems to be correct in regards to runtime PM. It should produce some
prints to the log, particular during power on/off of the SDIO card and
during probe of the wifi driver. Please re-run the test on top of the
v2 version of the $subject patch.

Kind regards
Uffe
From ef7890463ae9bec8fab7d16448681923736706e3 Mon Sep 17 00:00:00 2001
From: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Date: Mon, 21 Jan 2019 15:31:57 +0100
Subject: [PATCH] wlcore/sdio/mmc: Debug for runtime PM and power on/off of
SDIO

Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---
drivers/mmc/core/pwrseq_simple.c | 2 ++
drivers/mmc/core/sdio.c | 19 +++++++++++++++++--
drivers/mmc/core/sdio_bus.c | 26 +++++++++++++++++++++++---
drivers/net/wireless/ti/wlcore/sdio.c | 27 ++++++++++++++++++++++++++-
4 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
index ece34c734693..b9b1fc73a5a0 100644
--- a/drivers/mmc/core/pwrseq_simple.c
+++ b/drivers/mmc/core/pwrseq_simple.c
@@ -66,6 +66,7 @@ static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
clk_prepare_enable(pwrseq->ext_clk);
pwrseq->clk_enabled = true;
+ dev_info(mmc_dev(host), "%s clk_prepare_enable()\n", __func__);
}

mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
@@ -94,6 +95,7 @@ static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
clk_disable_unprepare(pwrseq->ext_clk);
pwrseq->clk_enabled = false;
+ dev_info(mmc_dev(host), "%s clk_disable_unprepare()\n", __func__);
}
}

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index d8e17ea6126d..ce7d29ad2651 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -1029,11 +1029,13 @@ static int mmc_sdio_power_restore(struct mmc_host *host)

static int mmc_sdio_runtime_suspend(struct mmc_host *host)
{
+ dev_info(&host->card->dev, "%s\n", __func__);
/* No references to the card, cut the power to it. */
mmc_claim_host(host);
mmc_power_off(host);
mmc_release_host(host);

+ dev_info(&host->card->dev, "%s - DONE\n", __func__);
return 0;
}

@@ -1041,19 +1043,27 @@ static int mmc_sdio_runtime_resume(struct mmc_host *host)
{
int ret;

+ dev_info(&host->card->dev, "%s\n", __func__);
/* Restore power and re-initialize. */
mmc_claim_host(host);
mmc_power_up(host, host->card->ocr);
ret = mmc_sdio_power_restore(host);
mmc_release_host(host);

+ dev_info(&host->card->dev, "%s - ret=%d DONE\n", __func__, ret);
return ret;
}

static int mmc_sdio_hw_reset(struct mmc_host *host)
{
+ int ret;
+
+ dev_info(&host->card->dev, "%s\n", __func__);
mmc_power_cycle(host, host->card->ocr);
- return mmc_sdio_power_restore(host);
+ ret = mmc_sdio_power_restore(host);
+
+ dev_info(&host->card->dev, "%s - ret=%d DONE\n", __func__, ret);
+ return ret;
}

static int mmc_sdio_sw_reset(struct mmc_host *host)
@@ -1142,6 +1152,8 @@ int mmc_attach_sdio(struct mmc_host *host)
* Enable runtime PM for this card
*/
pm_runtime_enable(&card->dev);
+
+ dev_info(&card->dev, "%s Enabled runtime PM()\n", __func__);
}

/*
@@ -1183,8 +1195,11 @@ int mmc_attach_sdio(struct mmc_host *host)
goto remove_added;
}

- if (host->caps & MMC_CAP_POWER_OFF_CARD)
+
+ if (host->caps & MMC_CAP_POWER_OFF_CARD) {
+ dev_info(&card->dev, "%s pm_runtime_put()\n", __func__);
pm_runtime_put(&card->dev);
+ }

mmc_claim_host(host);
return 0;
diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index b6d8203e46eb..e4357ce188ef 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c
@@ -134,6 +134,8 @@ static int sdio_bus_probe(struct device *dev)
const struct sdio_device_id *id;
int ret;

+ dev_info(dev, "%s\n", __func__);
+
id = sdio_match_device(func, drv);
if (!id)
return -ENODEV;
@@ -149,6 +151,7 @@ static int sdio_bus_probe(struct device *dev)
* pm_runtime_get_noresume() in its remove routine.
*/
if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD) {
+ dev_info(dev, "%s - pm_runtime_get_sync()\n", __func__);
ret = pm_runtime_get_sync(dev);
if (ret < 0)
goto disable_runtimepm;
@@ -166,11 +169,14 @@ static int sdio_bus_probe(struct device *dev)
if (ret)
goto disable_runtimepm;

+ dev_info(dev, "%s - probe OK\n", __func__);
return 0;

disable_runtimepm:
- if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD)
+ if (func->card->host->caps & MMC_CAP_POWER_OFF_CARD) {
+ dev_info(dev, "%s - ERR call pm_runtime_put_noidle()\n", __func__);
pm_runtime_put_noidle(dev);
+ }
dev_pm_domain_detach(dev, false);
return ret;
}
@@ -208,11 +214,25 @@ static int sdio_bus_remove(struct device *dev)
return ret;
}

+#ifdef CONFIG_PM
+static int sdio_bus_runtime_suspend(struct device *dev)
+{
+ dev_info(dev, "%s\n", __func__);
+ return pm_generic_runtime_suspend(dev);
+}
+
+static int sdio_bus_runtime_resume(struct device *dev)
+{
+ dev_info(dev, "%s\n", __func__);
+ return pm_generic_runtime_resume(dev);
+}
+#endif
+
static const struct dev_pm_ops sdio_bus_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
SET_RUNTIME_PM_OPS(
- pm_generic_runtime_suspend,
- pm_generic_runtime_resume,
+ sdio_bus_runtime_suspend,
+ sdio_bus_runtime_resume,
NULL
)
};
diff --git a/drivers/net/wireless/ti/wlcore/sdio.c b/drivers/net/wireless/ti/wlcore/sdio.c
index 4d4b07701149..0a82a11cae97 100644
--- a/drivers/net/wireless/ti/wlcore/sdio.c
+++ b/drivers/net/wireless/ti/wlcore/sdio.c
@@ -154,6 +154,8 @@ static int wl12xx_sdio_power_on(struct wl12xx_sdio_glue *glue)
struct sdio_func *func = dev_to_sdio_func(glue->dev);
struct mmc_card *card = func->card;

+ dev_info(glue->dev, "%s: STEP1\n", __func__);
+
ret = pm_runtime_get_sync(&card->dev);
if (ret < 0) {
pm_runtime_put_noidle(&card->dev);
@@ -163,7 +165,12 @@ static int wl12xx_sdio_power_on(struct wl12xx_sdio_glue *glue)
return ret;
}

+ dev_info(glue->dev, "%s: STEP2\n", __func__);
+
sdio_claim_host(func);
+
+ dev_info(glue->dev, "%s: STEP3\n", __func__);
+
/*
* To guarantee that the SDIO card is power cycled, as required to make
* the FW programming to succeed, let's do a brute force HW reset.
@@ -171,8 +178,12 @@ static int wl12xx_sdio_power_on(struct wl12xx_sdio_glue *glue)
mmc_hw_reset(card->host);

sdio_enable_func(func);
+
+ dev_info(glue->dev, "%s: STEP4\n", __func__);
+
sdio_release_host(func);

+ dev_info(glue->dev, "%s: STEP5\n", __func__);
return 0;
}

@@ -181,12 +192,20 @@ static int wl12xx_sdio_power_off(struct wl12xx_sdio_glue *glue)
struct sdio_func *func = dev_to_sdio_func(glue->dev);
struct mmc_card *card = func->card;

+ dev_info(glue->dev, "%s: STEP1\n", __func__);
+
sdio_claim_host(func);
sdio_disable_func(func);
+
+ dev_info(glue->dev, "%s: STEP2\n", __func__);
sdio_release_host(func);

+
+ dev_info(glue->dev, "%s: STEP3\n", __func__);
/* Let runtime PM know the card is powered off */
pm_runtime_put(&card->dev);
+
+ dev_info(glue->dev, "%s: STEP4\n", __func__);
return 0;
}

@@ -315,7 +334,7 @@ static int wl1271_probe(struct sdio_func *func,

/* if sdio can keep power while host is suspended, enable wow */
mmcflags = sdio_get_host_pm_caps(func);
- dev_dbg(glue->dev, "sdio PM caps = 0x%x\n", mmcflags);
+ dev_info(glue->dev, "sdio PM caps = 0x%x\n", mmcflags);

if (mmcflags & MMC_PM_KEEP_POWER)
pdev_data->pwr_in_suspend = true;
@@ -336,6 +355,8 @@ static int wl1271_probe(struct sdio_func *func,
else
chip_family = "wl12xx";

+ dev_info(glue->dev, "chip_family is %s\n", chip_family);
+
glue->core = platform_device_alloc(chip_family, PLATFORM_DEVID_AUTO);
if (!glue->core) {
dev_err(glue->dev, "can't allocate platform_device");
@@ -375,11 +396,15 @@ static int wl1271_probe(struct sdio_func *func,
goto out_dev_put;
}

+ dev_info(glue->dev, "About to add core dev (child)...\n");
+
ret = platform_device_add(glue->core);
if (ret) {
dev_err(glue->dev, "can't add platform device\n");
goto out_dev_put;
}
+
+ dev_info(glue->dev, "...added core dev (child) - probe complete!\n");
return 0;

out_dev_put:
--
2.17.1