From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ritesh Harjani Subject: Re: [PATCH v3 7/9] mmc: sdhci-msm: Implement set_clock callback for sdhci-msm Date: Tue, 23 Aug 2016 19:09:59 +0530 Message-ID: <88b87649-8ddf-102d-029b-851456991561@codeaurora.org> References: <1471581384-18961-1-git-send-email-riteshh@codeaurora.org> <1471581384-18961-8-git-send-email-riteshh@codeaurora.org> <4e1be7e8-ad6e-b52f-d5ad-258a6d4ed41d@intel.com> <614e25fb-34ad-285d-2abc-0748c89a9c0a@codeaurora.org> <47795735-66ae-5382-77fa-7906833aada0@intel.com> <9200ab14-ffdc-8a50-51e2-0572dcea6b95@intel.com> <0dc5e388-dbc3-6179-6b27-c35afffd6bb8@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org To: Adrian Hunter Cc: ulf.hansson@linaro.org, bjorn.andersson@linaro.org, shawn.lin@rock-chips.com, jh80.chung@samsung.com, linux-mmc@vger.kernel.org, linux-arm-msm@vger.kernel.org, georgi.djakov@linaro.org, alex.lemberg@sandisk.com, mateusz.nowak@intel.com, Yuliy.Izrailov@sandisk.com, asutoshd@codeaurora.org, kdorfman@codeaurora.org, david.griego@linaro.org, stummala@codeaurora.org, venkatg@codeaurora.org List-Id: linux-arm-msm@vger.kernel.org Hi, On 8/23/2016 6:47 PM, Adrian Hunter wrote: > On 22/08/16 15:56, Ritesh Harjani wrote: >> Hi Adrian, >> >> >> On 8/22/2016 2:59 PM, Adrian Hunter wrote: >>> On 22/08/16 12:07, Ritesh Harjani wrote: >>>> Hi Adrian, >>>> >>>> >>>> On 8/22/2016 11:50 AM, Adrian Hunter wrote: >>>>> On 19/08/16 16:31, Ritesh Harjani wrote: >>>>>> Hi, >>>>>> >>>>>> >>>>>> On 8/19/2016 6:34 PM, Adrian Hunter wrote: >>>>>>> On 19/08/16 07:36, Ritesh Harjani wrote: >>>>>>>> sdhci-msm controller may have different clk-rates for each >>>>>>>> bus speed mode. Thus implement set_clock callback for >>>>>>>> sdhci-msm driver. >>>>>>>> >>>>>>>> Signed-off-by: Sahitya Tummala >>>>>>>> Signed-off-by: Ritesh Harjani >>>>>>>> --- >>>>>>>> drivers/mmc/host/sdhci-msm.c | 103 >>>>>>>> ++++++++++++++++++++++++++++++++++++++++++- >>>>>>>> 1 file changed, 102 insertions(+), 1 deletion(-) >>>>>>>> >>>>>>>> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c >>>>>>>> index 7c032c3..c0ad9c2 100644 >>>>>>>> --- a/drivers/mmc/host/sdhci-msm.c >>>>>>>> +++ b/drivers/mmc/host/sdhci-msm.c >>>>>>>> @@ -89,6 +89,7 @@ struct sdhci_msm_host { >>>>>>>> struct mmc_host *mmc; >>>>>>>> bool use_14lpp_dll_reset; >>>>>>>> struct sdhci_msm_pltfm_data *pdata; >>>>>>>> + u32 clk_rate; >>>>>>>> }; >>>>>>>> >>>>>>>> /* Platform specific tuning */ >>>>>>>> @@ -582,6 +583,106 @@ static unsigned int sdhci_msm_get_min_clock(struct >>>>>>>> sdhci_host *host) >>>>>>>> return msm_host->pdata->clk_table[0]; >>>>>>>> } >>>>>>>> >>>>>>>> +static unsigned int sdhci_msm_get_msm_clk_rate(struct sdhci_host *host, >>>>>>>> + u32 req_clk) >>>>>>>> +{ >>>>>>>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); >>>>>>>> + struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); >>>>>>>> + int count = msm_host->pdata->clk_table_sz; >>>>>>>> + unsigned int sel_clk = -1; >>>>>>>> + int cnt; >>>>>>>> + >>>>>>>> + if (req_clk < sdhci_msm_get_min_clock(host)) { >>>>>>>> + sel_clk = sdhci_msm_get_min_clock(host); >>>>>>>> + return sel_clk; >>>>>>>> + } >>>>>>>> + >>>>>>>> + for (cnt = 0; cnt < count; cnt++) { >>>>>>>> + if (msm_host->pdata->clk_table[cnt] > req_clk) { >>>>>>>> + break; >>>>>>>> + } else if (msm_host->pdata->clk_table[cnt] == req_clk) { >>>>>>>> + sel_clk = msm_host->pdata->clk_table[cnt]; >>>>>>>> + break; >>>>>>>> + } else { >>>>>>>> + sel_clk = msm_host->pdata->clk_table[cnt]; >>>>>>>> + } >>>>>>>> + } >>>>>>> >>>>>>> 'else' is not needed after 'break' but can't this be simpler e.g. >>>>>>> >>>>>>> static unsigned int sdhci_msm_get_msm_clk_rate(struct sdhci_msm_host >>>>>>> *msm_host, u32 req_clk) >>>>>>> { >>>>>>> int count = msm_host->pdata->clk_table_sz; >>>>>>> unsigned int sel_clk = -1; >>>>>>> >>>>>>> while (count--) { >>>>>>> sel_clk = msm_host->pdata->clk_table[count]; >>>>>>> if (req_clk >= sel_clk) >>>>>>> return sel_clk; >>>>>>> } >>>>>>> >>>>>>> return sel_clk; >>>>>>> } >>>>>> >>>>>> Ok, sure I will check and get back on this. >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>>> + return sel_clk; >>>>>>>> +} >>>>>>> >>>>>>> Blank line needed >>>>>> Ok done. >>>>>> >>>>>>> >>>>>>>> +/** >>>>>>>> + * __sdhci_msm_set_clock - sdhci_msm clock control. >>>>>>>> + * >>>>>>>> + * Description: >>>>>>>> + * Implement MSM version of sdhci_set_clock. >>>>>>>> + * This is required since MSM controller does not >>>>>>>> + * use internal divider and instead directly control >>>>>>>> + * the GCC clock as per HW recommendation. >>>>>>>> + **/ >>>>>>>> +void __sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock) >>>>>>>> +{ >>>>>>>> + u16 clk; >>>>>>>> + unsigned long timeout; >>>>>>>> + >>>>>>>> + host->mmc->actual_clock = 0; >>>>>>>> + >>>>>>>> + sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL); >>>>>>>> + >>>>>>>> + if (clock == 0) >>>>>>>> + return; >>>>>>> >>>>>>> Should set host->mmc->actual_clock to the actual rate somewhere. >>>>>> Since MSM controller does not uses divider then there is no need of having >>>>>> actual clock since it should be same as host->clock. >>>>> >>>>> Ok, so sdhci_msm_get_msm_clk_rate() is not the actual clock rate? >>>> So I was assuming we need host->mmc->actual_clock rate if host->clock is not >>>> the actual rate. >>>> Ok, so I will update actual_clock to host->clock itself. >>>> >>>> pls, let me know if any concerns. >>> >>> I am confused. Isn't clk_get_rate(msm_host->clk) the actual clock rate? >> >> Actually, msm controller have few quirks around clocks itself and >> I was thinking of not using actual_clock to avoid adding any extra quirks >> for msm. >> >> If you see if actual_clock is 0 and if SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK >> is set, timeout_clk take host->clock for timeout calculation. >> >> That's one reason I did not want to update the host->actual_clock. >> (otherwise timeout calc will go wrong for DDR modes for msm, where clock >> from GCC is made double of host->clock and internally divided by controller >> on it's own. In this case actual_clock would be shown as 2x of host->clock). >> Do you think that keeping actual_clock to 0 should be fine in this case? > > Yes, but please add a comment in the code. Sure thanks. I will address all comments in v4 spin. > >> >> >> I have not yet worked over timeout calculation patches yet, since it is of >> lower priority in my list. After few other areas (mostly HS400), I will take >> over clock timeout fixes to be up-streamed. >> >>> >>>>> >>>>>> >>>>>> That's why I had kept it 0 intentionally. But I will add a comment >>>>>> here then. >>>>>> >>>>>>> >>>>>>>> + >>>>>>>> + /* >>>>>>>> + * MSM controller do not use clock divider. >>>>>>>> + * Thus read SDHCI_CLOCK_CONTROL and only enable >>>>>>>> + * clock with no divider value programmed. >>>>>>>> + */ >>>>>>>> + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL); >>>>>>>> + >>>>>>>> + clk |= SDHCI_CLOCK_INT_EN; >>>>>>>> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); >>>>>>>> + >>>>>>>> + /* Wait max 20 ms */ >>>>>>>> + timeout = 20; >>>>>>>> + while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL)) >>>>>>>> + & SDHCI_CLOCK_INT_STABLE)) { >>>>>>>> + if (timeout == 0) { >>>>>>>> + pr_err("%s: Internal clock never stabilised.\n", >>>>>>>> + mmc_hostname(host->mmc)); >>>>>>>> + return; >>>>>>>> + } >>>>>>>> + timeout--; >>>>>>>> + mdelay(1); >>>>>>>> + } >>>>>>>> + >>>>>>>> + clk |= SDHCI_CLOCK_CARD_EN; >>>>>>>> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); >>>>>>>> +} >>>>>>>> + >>>>>>>> +static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int >>>>>>>> clock) >>>>>>>> +{ >>>>>>>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); >>>>>>>> + struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); >>>>>>>> + u32 msm_clock = 0; >>>>>>>> + int rc = 0; >>>>>>>> + >>>>>>>> + if (!clock) >>>>>>>> + goto out; >>>>>>>> + >>>>>>>> + if (clock != msm_host->clk_rate) { >>>>>>>> + msm_clock = sdhci_msm_get_msm_clk_rate(host, clock); >>>>>>>> + rc = clk_set_rate(msm_host->clk, msm_clock); >>>>>>>> + if (rc) { >>>>>>>> + pr_err("%s: failed to set clock at rate %u, requested clock >>>>>>>> rate %u\n", >>>>>>>> + mmc_hostname(host->mmc), msm_clock, clock); >>>>>>>> + goto out; >>>>>>>> + } >>>>>>>> + msm_host->clk_rate = clock; >>>>>>>> + pr_debug("%s: setting clock at rate %lu\n", >>>>>>>> + mmc_hostname(host->mmc), clk_get_rate(msm_host->clk)); >>>>>>>> + } >>>>>>>> +out: >>>>>>>> + __sdhci_msm_set_clock(host, clock); >>>>>>>> +} >>>>>>>> + >>>>>>>> static const struct of_device_id sdhci_msm_dt_match[] = { >>>>>>>> { .compatible = "qcom,sdhci-msm-v4" }, >>>>>>>> {}, >>>>>>>> @@ -592,7 +693,7 @@ 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, >>>>>>>> - .set_clock = sdhci_set_clock, >>>>>>>> + .set_clock = sdhci_msm_set_clock, >>>>>>>> .get_min_clock = sdhci_msm_get_min_clock, >>>>>>>> .get_max_clock = sdhci_msm_get_max_clock, >>>>>>>> .set_bus_width = sdhci_set_bus_width, >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> > > -- > 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 >