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SubjectRe: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation
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Hi Georgi,

On 11/28/2016 11:09 PM, Georgi Djakov wrote:
> On apq8016, apq8084 and apq8074 platforms, writing to the software
> reset register triggers the "power irq". We need to ack and handle
> the irq, otherwise the following message appears:
>
> mmc0: Reset 0x1 never completed.
> sdhci: =========== REGISTER DUMP (mmc0)===========
> sdhci: Sys addr: 0x00000000 | Version: 0x00002e02
> sdhci: Blk size: 0x00004000 | Blk cnt: 0x00000000
> sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
> sdhci: Present: 0x01f80000 | Host ctl: 0x00000000
> sdhci: Power: 0x00000000 | Blk gap: 0x00000000
> sdhci: Wake-up: 0x00000000 | Clock: 0x00000003
> sdhci: Timeout: 0x00000000 | Int stat: 0x00000000
> sdhci: Int enab: 0x00000000 | Sig enab: 0x00000000
> sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
> sdhci: Caps: 0x322dc8b2 | Caps_1: 0x00008007
> sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
> sdhci: Host ctl2: 0x00000000
> sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x0000000000000000
> sdhci: ===========================================
>
> Fix it by implementing the custom sdhci_reset() function,
> which performs the software reset and then handles the irq.
>
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---
>
> Changes since v1: (https://lkml.org/lkml/2016/11/22/411)
> * Perform the software reset by just writing to the SDHCI_SOFTWARE_RESET
> register and then check for the irq.
I am still not sure about this change. Below change will trigger the
IRQ, once this call is completed (say on a single core system) -since
this is called while holding spin_lock_irqsave.

But you will be end up calling sdhci_msm_voltage_switch twice,
which to me does not seems correct.
1. 1st time you are directly calling it in sdhci_msm_reset.
2. 2nd time will be called from within pwr_irq to handle the same case.

Please let me know your thoughts on this ?

Regards
Ritesh

>
> drivers/mmc/host/sdhci-msm.c | 29 ++++++++++++++++++++++++++++-
> 1 file changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 32879b845b75..157ae07f9309 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -1019,6 +1019,33 @@ static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock)
> __sdhci_msm_set_clock(host, clock);
> }
>
> +void sdhci_msm_reset(struct sdhci_host *host, u8 mask)
> +{
> + unsigned long timeout = 100;
> +
> + sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET);
> +
> + if (mask & SDHCI_RESET_ALL) {
> + host->clock = 0;
> +
> + /*
> + * SDHCI_RESET_ALL triggers the PWR IRQ and we need
> + * to handle it here.
> + */
> + sdhci_msm_voltage_switch(host);
> + }
> +
> + while (sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask) {
> + if (timeout == 0) {
> + pr_err("%s: Reset 0x%x never completed.\n",
> + mmc_hostname(host->mmc), (int)mask);
> + return;
> + }
> + timeout--;
> + mdelay(1);
> + }
> +}
> +
> static const struct of_device_id sdhci_msm_dt_match[] = {
> { .compatible = "qcom,sdhci-msm-v4" },
> {},
> @@ -1028,7 +1055,7 @@ MODULE_DEVICE_TABLE(of, sdhci_msm_dt_match);
>
> static const struct sdhci_ops sdhci_msm_ops = {
> .platform_execute_tuning = sdhci_msm_execute_tuning,
> - .reset = sdhci_reset,
> + .reset = sdhci_msm_reset,
> .set_clock = sdhci_msm_set_clock,
> .get_min_clock = sdhci_msm_get_min_clock,
> .get_max_clock = sdhci_msm_get_max_clock,
> --
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>

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