From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932725AbeCSKBO (ORCPT ); Mon, 19 Mar 2018 06:01:14 -0400 Received: from mga04.intel.com ([192.55.52.120]:33457 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932375AbeCSKBJ (ORCPT ); Mon, 19 Mar 2018 06:01:09 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,330,1517904000"; d="scan'208";a="29215719" Subject: Re: [PATCH v3 07/11] mmc: sdhci: Program a relatively accurate SW timeout value To: Kishon Vijay Abraham I , Ulf Hansson , Tony Lindgren Cc: Rob Herring , Mark Rutland , Russell King , linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20180307132020.30951-1-kishon@ti.com> <20180307132020.30951-8-kishon@ti.com> <1e87e5f9-13e1-765b-f077-26a55359b2c3@intel.com> <47752066-aeda-87bc-6928-1a9b80f1c45c@ti.com> <49210daa-b593-4b34-abf5-be81580723bc@intel.com> <29f640ac-b155-41c6-cf3f-8c66e1b300f1@ti.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <1905d25f-d16d-50b1-54b0-35807d801a12@intel.com> Date: Mon, 19 Mar 2018 12:00:15 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <29f640ac-b155-41c6-cf3f-8c66e1b300f1@ti.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/03/18 11:20, Kishon Vijay Abraham I wrote: > Hi Adrian, > > On Friday 16 March 2018 07:51 PM, Adrian Hunter wrote: >> On 16/03/18 08:29, Kishon Vijay Abraham I wrote: >>> Hi, >>> >>> On Thursday 15 March 2018 06:43 PM, Adrian Hunter wrote: >>>> On 07/03/18 15:20, Kishon Vijay Abraham I wrote: >>>>> sdhci has a 10 second timeout to catch devices that stop responding. >>>>> Instead of programming 10 second arbitrary value, calculate the total time >>>>> it would take for the entire transfer to happen and program the timeout >>>>> value accordingly. >>>>> >>>>> Signed-off-by: Kishon Vijay Abraham I >>>>> --- >>>>> drivers/mmc/host/sdhci.c | 47 ++++++++++++++++++++++++++++++++++++++++------- >>>>> drivers/mmc/host/sdhci.h | 10 ++++++++++ >>>>> 2 files changed, 50 insertions(+), 7 deletions(-) >>>>> >>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >>>>> index 1dd117cbeb6e..baab67bfa39b 100644 >>>>> --- a/drivers/mmc/host/sdhci.c >>>>> +++ b/drivers/mmc/host/sdhci.c >>>>> @@ -709,6 +709,36 @@ static u32 sdhci_sdma_address(struct sdhci_host *host) >>>>> return sg_dma_address(host->data->sg); >>>>> } >>>>> >>>>> +static void sdhci_calc_sw_timeout(struct sdhci_host *host, >>>>> + struct mmc_command *cmd, >>>>> + unsigned int target_timeout) >>>>> +{ >>>>> + struct mmc_data *data = cmd->data; >>>>> + struct mmc_host *mmc = host->mmc; >>>>> + u64 transfer_time; >>>>> + struct mmc_ios *ios = &mmc->ios; >>>>> + unsigned char bus_width = 1 << ios->bus_width; >>>>> + unsigned int blksz; >>>>> + unsigned int freq; >>>>> + >>>>> + if (data) { >>>>> + blksz = data->blksz; >>>>> + freq = host->mmc->actual_clock ? : host->clock; >>>>> + transfer_time = (u64)blksz * NSEC_PER_SEC * (8 / bus_width); >>>>> + do_div(transfer_time, freq); >>>>> + /* multiply by '2' to account for any unknowns */ >>>>> + transfer_time = transfer_time * 2; >>>>> + /* calculate timeout for the entire data */ >>>>> + host->data_timeout = (data->blocks * ((target_timeout * >>>>> + NSEC_PER_USEC) + >>>>> + transfer_time)); >>>> >>>> (target_timeout * NSEC_PER_USEC) might be 32-bit and therefore overflow >>>> for timeouts greater than about 4 seconds. >>>> >>>>> + } else { >>>>> + host->data_timeout = (u64)target_timeout * NSEC_PER_USEC; >>>>> + } >>>>> + >>>>> + host->data_timeout += MMC_CMD_TRANSFER_TIME; >>>> >>>> Need to allow for target_timeout == 0 so: >>>> >>>> if (host->data_timeout) >>>> host->data_timeout += MMC_CMD_TRANSFER_TIME; >>>> >>>>> +} >>>>> + >>>>> static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd) >>>>> { >>>>> u8 count; >>>>> @@ -766,6 +796,7 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd) >>>>> if (count >= 0xF) >>>>> break; >>>>> } >>>>> + sdhci_calc_sw_timeout(host, cmd, target_timeout); >>>> >>>> If you make the changes I suggest for patch 6, then this would >>>> move sdhci_calc_sw_timeout() into sdhci_set_timeout(). >>>> >>>> I suggest you factor out the target_timeout calculation e.g. >>>> >>>> static unsigned int sdhci_target_timeout(struct sdhci_host *host, >>>> struct mmc_command *cmd, >>>> struct mmc_data *data) >>>> { >>>> unsigned int target_timeout; >>>> >>>> /* timeout in us */ >>>> if (!data) >>>> target_timeout = cmd->busy_timeout * 1000; >>>> else { >>>> target_timeout = DIV_ROUND_UP(data->timeout_ns, 1000); >>>> if (host->clock && data->timeout_clks) { >>>> unsigned long long val; >>>> >>>> /* >>>> * data->timeout_clks is in units of clock cycles. >>>> * host->clock is in Hz. target_timeout is in us. >>>> * Hence, us = 1000000 * cycles / Hz. Round up. >>>> */ >>>> val = 1000000ULL * data->timeout_clks; >>>> if (do_div(val, host->clock)) >>>> target_timeout++; >>>> target_timeout += val; >>>> } >>>> } >>>> >>>> return target_timeout; >>>> } >>>> >>>> And call it from sdhci_calc_sw_timeout() >>>> >>>>> >>>>> return count; >>>>> } >>>>> @@ -1175,13 +1206,6 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd) >>>>> mdelay(1); >>>>> } >>>>> >>>>> - timeout = jiffies; >>>>> - if (!cmd->data && cmd->busy_timeout > 9000) >>>>> - timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ; >>>>> - else >>>>> - timeout += 10 * HZ; >>>>> - sdhci_mod_timer(host, cmd->mrq, timeout); >>>>> - >>>>> host->cmd = cmd; >>>>> if (sdhci_data_line_cmd(cmd)) { >>>>> WARN_ON(host->data_cmd); >>>>> @@ -1221,6 +1245,15 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd) >>>>> cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200) >>>>> flags |= SDHCI_CMD_DATA; >>>>> >>>>> + timeout = jiffies; >>>>> + if (host->data_timeout > 0) { >>>> >>>> This can be just: >>>> >>>> if (host->data_timeout) { >>>> >>>>> + timeout += nsecs_to_jiffies(host->data_timeout); >>>>> + host->data_timeout = 0; >>>> >>>> It would be better to initialize host->data_timeout = 0 at the top of >>>> sdhci_prepare_data(). >>>> >>>> Also still need: >>>> >>>> else if (!cmd->data && cmd->busy_timeout > 9000) { >>>> timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ; >>> >>> sdhci_calc_sw_timeout should have calculated the timeout for this case too no? >> >> Yes, but I was thinking you would only calculate when it was needed. > > I feel since we would have anyways calculated data_timeout, we should use that > instead unless you see a problem with that. I would prefer not to calculate data_timeout when a hardware timeout is being used.