Re: [PATCH v2 1/2] sdhci: tegra: Implement Tegra specific set_timeout callback

From: Sowjanya Komatineni
Date: Thu Apr 16 2020 - 12:29:45 EST



On 4/16/20 3:59 AM, Ulf Hansson wrote:
External email: Use caution opening links or attachments


On Wed, 15 Apr 2020 at 19:55, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
On Fri, 13 Mar 2020 at 06:41, Sowjanya Komatineni
<skomatineni@xxxxxxxxxx> wrote:
Tegra host supports HW busy detection and timeouts based on the
count programmed in SDHCI_TIMEOUT_CONTROL register and max busy
timeout it supports is 11s in finite busy wait mode.

Some operations like SLEEP_AWAKE, ERASE and flush cache through
SWITCH commands take longer than 11s and Tegra host supports
infinite HW busy wait mode where HW waits forever till the card
is busy without HW timeout.

This patch implements Tegra specific set_timeout sdhci_ops to allow
switching between finite and infinite HW busy detection wait modes
based on the device command expected operation time.

Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
drivers/mmc/host/sdhci-tegra.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index a25c3a4..fa8f6a4 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -45,6 +45,7 @@
#define SDHCI_TEGRA_CAP_OVERRIDES_DQS_TRIM_SHIFT 8

#define SDHCI_TEGRA_VENDOR_MISC_CTRL 0x120
+#define SDHCI_MISC_CTRL_ERASE_TIMEOUT_LIMIT BIT(0)
#define SDHCI_MISC_CTRL_ENABLE_SDR104 0x8
#define SDHCI_MISC_CTRL_ENABLE_SDR50 0x10
#define SDHCI_MISC_CTRL_ENABLE_SDHCI_SPEC_300 0x20
@@ -1227,6 +1228,34 @@ static u32 sdhci_tegra_cqhci_irq(struct sdhci_host *host, u32 intmask)
return 0;
}

+static void tegra_sdhci_set_timeout(struct sdhci_host *host,
+ struct mmc_command *cmd)
+{
+ u32 val;
+
+ /*
+ * HW busy detection timeout is based on programmed data timeout
+ * counter and maximum supported timeout is 11s which may not be
+ * enough for long operations like cache flush, sleep awake, erase.
+ *
+ * ERASE_TIMEOUT_LIMIT bit of VENDOR_MISC_CTRL register allows
+ * host controller to wait for busy state until the card is busy
+ * without HW timeout.
+ *
+ * So, use infinite busy wait mode for operations that may take
+ * more than maximum HW busy timeout of 11s otherwise use finite
+ * busy wait mode.
+ */
+ val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_MISC_CTRL);
+ if (cmd && cmd->busy_timeout >= 11 * HZ)
+ val |= SDHCI_MISC_CTRL_ERASE_TIMEOUT_LIMIT;
+ else
+ val &= ~SDHCI_MISC_CTRL_ERASE_TIMEOUT_LIMIT;
+ sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_MISC_CTRL);
+
+ __sdhci_set_timeout(host, cmd);
kernel build on arm and arm64 architecture failed on stable-rc 4.19
(arm), 5.4 (arm64) and 5.5 (arm64)

drivers/mmc/host/sdhci-tegra.c: In function 'tegra_sdhci_set_timeout':
drivers/mmc/host/sdhci-tegra.c:1256:2: error: implicit declaration of
function '__sdhci_set_timeout'; did you mean
'tegra_sdhci_set_timeout'? [-Werror=implicit-function-declaration]
__sdhci_set_timeout(host, cmd);
^~~~~~~~~~~~~~~~~~~
tegra_sdhci_set_timeout

Full build log,
https://ci.linaro.org/view/lkft/job/openembedded-lkft-linux-stable-rc-5.5/DISTRO=lkft,MACHINE=am57xx-evm,label=docker-lkft/83/consoleText
https://ci.linaro.org/view/lkft/job/openembedded-lkft-linux-stable-rc-5.4/DISTRO=lkft,MACHINE=juno,label=docker-lkft/158/consoleText
https://ci.linaro.org/view/lkft/job/openembedded-lkft-linux-stable-rc-4.19/DISTRO=lkft,MACHINE=am57xx-evm,label=docker-lkft/511/consoleText

- Naresh
Thanks for reporting! What a mess.

It turns out that the commit that was queued for stable that is
causing the above errors, also requires another commit.

The commit that was queued:
5e958e4aacf4 ("sdhci: tegra: Implement Tegra specific set_timeout callback")

The additional commit needed (which was added in v5.6-rc1):
7d76ed77cfbd ("mmc: sdhci: Refactor sdhci_set_timeout()")

However, the above commit needs a manual backport (quite trivial, but
still) for the relevant stable kernels, to allow it to solve the build
problems.

Greg, Sasha - I suggest you to drop the offending commit from the
stable kernels, for now. I think it's better to let Sowjanya deal with
the backports, then send them in small series instead.

Kind regards
Uffe

Hi Ufee,

Will back-porting below commit cause any issues to other vendors?

7d76ed77cfbd ("mmc: sdhci: Refactor sdhci_set_timeout()")

Thanks
Sowjanya