Messages in this thread | | | Date | Fri, 25 Mar 2022 12:52:23 +0530 | Subject | Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC | From | "Sajida Bhanu (Temp)" <> |
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On 3/15/2022 2:47 PM, Sajida Bhanu (Temp) (QUIC) wrote: > Hi, > > Thanks for the review. > > Please find the inline comments. > > Thanks, > Sajida >> -----Original Message----- >> From: Bjorn Andersson <bjorn.andersson@linaro.org> >> Sent: Friday, March 11, 2022 5:10 AM >> To: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@quicinc.com> >> Cc: adrian.hunter@intel.com; agross@kernel.org; ulf.hansson@linaro.org; >> p.zabel@pengutronix.de; chris@printf.net; gdjakov@mm-sol.com; linux- >> mmc@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux- >> kernel@vger.kernel.org; Asutosh Das (QUIC) <quic_asutoshd@quicinc.com>; >> Ram Prakash Gupta (QUIC) <quic_rampraka@quicinc.com>; Pradeep >> Pragallapati (QUIC) <quic_pragalla@quicinc.com>; Sarthak Garg (QUIC) >> <quic_sartgarg@quicinc.com>; Nitin Rawat (QUIC) >> <quic_nitirawa@quicinc.com>; Sayali Lokhande (QUIC) >> <quic_sayalil@quicinc.com> >> Subject: Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for >> SDHC >> >> On Thu 10 Mar 07:40 PST 2022, Shaik Sajida Bhanu wrote: >> >>> Reset GCC_SDCC_BCR register before every fresh initilazation. This >>> will reset whole SDHC-msm controller, clears the previous power >>> control states and avoids, software reset timeout issues as below. >>> >> Nice, we've gotten reports about this from time to time. >> >>> [ 5.458061][ T262] mmc1: Reset 0x1 never completed. >>> [ 5.462454][ T262] mmc1: sdhci: ============ SDHCI REGISTER DUMP >>> =========== [ 5.469065][ T262] mmc1: sdhci: Sys addr: 0x00000000 | >>> Version: >>> 0x00007202 >>> [ 5.475688][ T262] mmc1: sdhci: Blk size: 0x00000000 | Blk cnt: >>> 0x00000000 >>> [ 5.482315][ T262] mmc1: sdhci: Argument: 0x00000000 | Trn mode: >>> 0x00000000 >>> [ 5.488927][ T262] mmc1: sdhci: Present: 0x01f800f0 | Host ctl: >>> 0x00000000 >>> [ 5.495539][ T262] mmc1: sdhci: Power: 0x00000000 | Blk gap: >>> 0x00000000 [ 5.502162][ T262] mmc1: sdhci: Wake-up: 0x00000000 | >>> Clock: 0x00000003 [ 5.508768][ T262] mmc1: sdhci: Timeout: 0x00000000 | >> Int stat: >>> 0x00000000 >>> [ 5.515381][ T262] mmc1: sdhci: Int enab: 0x00000000 | Sig enab: >>> 0x00000000 >>> [ 5.521996][ T262] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int: >>> 0x00000000 >>> [ 5.528607][ T262] mmc1: sdhci: Caps: 0x362dc8b2 | Caps_1: 0x0000808f >>> [ 5.535227][ T262] mmc1: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000 >>> [ 5.541841][ T262] mmc1: sdhci: Resp[0]: 0x00000000 | Resp[1]: >>> 0x00000000 >>> [ 5.548454][ T262] mmc1: sdhci: Resp[2]: 0x00000000 | Resp[3]: >>> 0x00000000 >>> [ 5.555079][ T262] mmc1: sdhci: Host ctl2: 0x00000000 [ 5.559651][ >>> T262] mmc1: sdhci_msm: ----------- VENDOR REGISTER >>> DUMP----------- >>> [ 5.566621][ T262] mmc1: sdhci_msm: DLL sts: 0x00000000 | DLL cfg: >>> 0x6000642c | >>> DLL cfg2: 0x0020a000 >>> [ 5.575465][ T262] mmc1: sdhci_msm: DLL cfg3: 0x00000000 | DLL usr ctl: >>> 0x00010800 | DDR cfg: 0x80040873 >>> [ 5.584658][ T262] mmc1: sdhci_msm: Vndr func: 0x00018a9c | Vndr func2 : >>> 0xf88218a8 Vndr func3: 0x02626040 >> Please ignore the line length "limit" and leave these unwrapped. >> > Sure >>> Fixes: 0eb0d9f4de34 ("mmc: sdhci-msm: Initial support for Qualcomm >>> chipsets") >> This as well, and please drop the empty line between Fixes: and Signed-off- >> by:. >> > Sure >>> Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@quicinc.com> >>> --- >>> >>> Changes since V1: >>> - Added fixes tag as suggested by Ulf Hansson. >>> - Replaced devm_reset_control_get() with >>> devm_reset_control_get_optional_exclusive() as suggested by >>> Ulf Hansson. >>> --- >>> drivers/mmc/host/sdhci-msm.c | 48 >>> ++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 48 insertions(+) >>> >>> diff --git a/drivers/mmc/host/sdhci-msm.c >>> b/drivers/mmc/host/sdhci-msm.c index 50c71e0..cb33c9a 100644 >>> --- a/drivers/mmc/host/sdhci-msm.c >>> +++ b/drivers/mmc/host/sdhci-msm.c >>> @@ -17,6 +17,7 @@ >>> #include <linux/regulator/consumer.h> #include >>> <linux/interconnect.h> #include <linux/pinctrl/consumer.h> >>> +#include <linux/reset.h> >>> >>> #include "sdhci-pltfm.h" >>> #include "cqhci.h" >>> @@ -284,6 +285,7 @@ struct sdhci_msm_host { >>> bool uses_tassadar_dll; >>> u32 dll_config; >>> u32 ddr_config; >>> + struct reset_control *core_reset; >> As you only reset the controller once, during probe, this can be a local >> variable in sdhci_msm_gcc_reset(). > Hi, > > In future if any requirement to reset gcc , for example if we want to reset gcc as a part of hardware reset then we can use this core_reset right. > > Thanks, > Sajida >>> bool vqmmc_enabled; >>> }; >>> >>> @@ -2482,6 +2484,45 @@ static inline void >> sdhci_msm_get_of_property(struct platform_device *pdev, >>> of_property_read_u32(node, "qcom,dll-config", >>> &msm_host->dll_config); } >>> >>> +static int sdhci_msm_gcc_reset(struct platform_device *pdev, >> You don't need pdev here, take a struct deivce * in and pass &pdev->dev. > Ok >>> + struct sdhci_host *host) >>> +{ >>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); >>> + struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); >>> + int ret = 0; >>> + >>> + msm_host->core_reset = >>> +devm_reset_control_get_optional_exclusive(&pdev->dev, >> "core_reset"); >> >> No need to hold onto that, so use the non-devm variant and free the reset at >> the end of the function. > Sorry didn't get this. > Can you please point me any reference for this.
Hi,
Can you please help with comment on this.
Thanks,
Sajida
>>> + if (IS_ERR(msm_host->core_reset)) { >>> + ret = PTR_ERR(msm_host->core_reset); >>> + dev_err(&pdev->dev, "core_reset unavailable (%d)\n", ret); >>> + msm_host->core_reset = NULL; >> return dev_err_probe(&pdev->dev, PTR_ERR(msm_host->core_reset), >> "unable to acquire core_reset\n"); >> >>> + } >>> + if (msm_host->core_reset) { >> If you flip this around as: >> >> if (!msm_host->core_reset) >> return 0; >> >> You don't need to zero-initialize ret, use goto and indent this block. > Sure >>> + ret = reset_control_assert(msm_host->core_reset); >>> + if (ret) { >>> + dev_err(&pdev->dev, "core_reset assert failed >> (%d)\n", >>> + ret); >>> + goto out; >> return dev_err_probe(); >> > Sure >>> + } >>> + /* >>> + * The hardware requirement for delay between >> assert/deassert >>> + * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to >>> + * ~125us (4/32768). To be on the safe side add 200us delay. >>> + */ >>> + usleep_range(200, 210); >>> + >>> + ret = reset_control_deassert(msm_host->core_reset); >>> + if (ret) { >>> + dev_err(&pdev->dev, "core_reset deassert failed >> (%d)\n", >>> + ret); >>> + goto out; >> return dev_err_probe() > Sure >>> + } >>> + usleep_range(200, 210); >> The comment above says that we need to hold reset for 125us, is this delay >> in here in error or should the comment above mention that this needs to be >> done after deasserting the reset as well? > Yes we need delay after deasserting the reset as well. >>> + } >>> + >>> +out: >>> + return ret; >> With above, you can return 0 here. >> >>> +} >>> >>> static int sdhci_msm_probe(struct platform_device *pdev) { @@ >>> -2529,6 +2570,13 @@ static int sdhci_msm_probe(struct platform_device >>> *pdev) >>> >>> msm_host->saved_tuning_phase = INVALID_TUNING_PHASE; >>> >>> + ret = sdhci_msm_gcc_reset(pdev, host); >>> + if (ret) { >>> + dev_err(&pdev->dev, "core_reset assert/deassert failed >> (%d)\n", >>> + ret); >> You just printed in sdhci_msm_gcc_reset(), no need to print again. >> >> Regards, >> Bjorn >> > Okay Sure >>> + goto pltfm_free; >>> + } >>> + >>> /* Setup SDCC bus voter clock. */ >>> msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus"); >>> if (!IS_ERR(msm_host->bus_clk)) { >>> -- >>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a >>> member of Code Aurora Forum, hosted by The Linux Foundation >>>
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