From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751838AbdARJZ7 (ORCPT ); Wed, 18 Jan 2017 04:25:59 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:48010 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751488AbdARJZd (ORCPT ); Wed, 18 Jan 2017 04:25:33 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 406F5607A5 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=riteshh@codeaurora.org Subject: Re: [PATCH v2] mmc: sdhci-msm: Add sdhci_reset() implementation To: Georgi Djakov References: <20161128173920.25334-1-georgi.djakov@linaro.org> <27e95224-ff32-954d-443a-2310c1225ca0@codeaurora.org> <7f35faac-7c04-8024-3111-9d4742ad2154@linaro.org> Cc: adrian.hunter@intel.com, ulf.hansson@linaro.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org From: Ritesh Harjani Message-ID: <2a63a412-ce5d-eb96-ac66-e6f73806c00f@codeaurora.org> Date: Wed, 18 Jan 2017 14:46:06 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Georgi, Sorry for delaying this. I did check with HW folks here, but it seems like we still don't have confirmation. In case if I get any new updates later, we can revisit it. Also I see that we have the same implementation in current driver for changing IO voltage. In that case I think this patch should be fine to avoid the error message on reboot. On 12/3/2016 2:24 PM, Ritesh Harjani wrote: > > > On 12/1/2016 11:38 PM, Georgi Djakov wrote: >> On 11/29/2016 05:40 AM, Ritesh Harjani wrote: >>> 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 >>>> --- Reviewed-by: Ritesh Harjani >>>> >>>> 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. >> >> Yes, that would be the behavior. This function actually is not doing >> anything much than to check irq status and ack it. Testing the patch > Ok. > >> on a few different platforms does not show any side effects, however i >> could not be 100% sure as i have limited information about the hardware. > what about the case when say the IRQ is delayed because of some other > overheads in the system. Will this approach still works? > I understand this would require some HW knowledge to understand the > functioning/importance of this pwr_irq. I will try and get in touch with > HW folk here. > > Regards > Ritesh > > >> >> Thanks, >> Georgi >> >>> >>> 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, >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >>>> the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project