On 26/07/22 05:56, Seunghui Lee wrote: >> -----Original Message----- >> From: Seunghui Lee <sh043.lee@xxxxxxxxxxx> >> Sent: Thursday, July 21, 2022 2:59 PM >> To: ulf.hansson@xxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; >> adrian.hunter@xxxxxxxxx >> Cc: Seunghui Lee <sh043.lee@xxxxxxxxxxx>; DooHyun Hwang >> <dh0421.hwang@xxxxxxxxxxx> >> Subject: [PATCH] mmc: sd: Remove the patch that fix signal voltage when >> there is no power cycle >> >> At first, all error flow of mmc_set_uhs_voltage() has power cycle except >> R1_ERROR and no start_signal_voltage_switch() func pointer. >> >> There is the performance regression issue of SDR104 SD card from the >> market VOC. Normally, once a SDR104 SD card fails to switch voltage, it >> works HS mode. >> And then it initializes SDR104 mode after system resume or error handling. >> >> However, with below patch, >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ >> drivers/mmc/core/sd.c?id=6a11fc47f175c8d87018e89cb58e2d36c66534cb >> Once a SD card does, it initializes SDR25 mode forever after system resume >> or error handling(re-initialized). >> Host updates sd3_bus_mode by calling mmc_read_switch(), the value of >> sd3_bus_mode doesn't set for SDR104, SDR50 and DDR50 mode. >> >> So, if host doesn't update sd3_bus_mode, the SD card works SDR104 mode >> after system resume or error-handling. >> >> Here is an example. >> >> AS-IS : test log >> // normal case : sd3_bus_mode = 0x1F, sd_bus_speed = SDR104, clock 208MHz >> [ 111.907789] [1: kworker/1:3: 772] [TEST] mmc_sd_init_card: 1119: >> caps=0x407f020f, sd3_bus_mode=0x1f, v18_fixup_failed false, signal_voltage >> =0x1. >> [ 111.907824] [1: kworker/1:3: 772] [TEST] mmc_sd_init_card: 1149: rocr >> 0xc1ff8000, S18A, uhs. >> [ 111.908707] [1: kworker/1:3: 772] [TEST] sd_update_bus_speed_mode: >> caps 0x407f020f, sd3_bus_mode = 0x1f, sd_bus_speed = 3, card->ocr = >> 0x40000. >> [ 111.912484] [1: kworker/1:3: 772] [TEST] sd_set_bus_speed_mode: >> sd_bus_speed=3, timing=6, uhs_max_dtr=208000000, card->ocr=0x40000. >> // resume : issue occurs : SDcard doesn't release busy for checking 10 >> times >> [ 112.096550] [5: kworker/5:2: 207] [TEST] mmc_sd_init_card: 1040: >> card->ocr 0x40000. >> [ 112.096560] [5: kworker/5:2: 207] [TEST] mmc_sd_get_cid: ocr >> 0x40000(pocr 0x40000), retries 10. >> ... >> [ 114.531129] [5: kworker/5:2: 207] [TEST] mmc_power_cycle. >> [ 114.579500] [5: kworker/5:2: 207] [TEST] mmc_sd_get_cid: ocr >> 0x41040000(pocr 0x40000), retries 0. >> [ 114.579506] [5: kworker/5:2: 207] mmc0: Skipping voltage switch >> [ 114.757575] [5: kworker/5:2: 207] [TEST] mmc_sd_init_card: 1119: >> caps=0x407f020f, sd3_bus_mode=0x1f, v18_fixup_failed false, signal_voltage >> =0x0. >> [ 114.757583] [5: kworker/5:2: 207] [TEST] mmc_sd_init_card: 1128: >> switch with oldcard. >> [ 114.759742] [5: kworker/5:2: 207] [TEST] mmc_read_switch: sd_switch >> ret 0, sd3_bus_mode=3. >> // sd3_bus_mode = 0x3 supports HS, SDR25 and SDR12 >> [ 114.759750] [5: kworker/5:2: 207] [TEST] mmc_sd_init_card: 1157: >> switch hs. >> // next resume : the SDcard initializes to SDR25(HS) mode(sd_bus_speed = 1) >> by sd3_bus_mode setting with clk 50MHz >> [ 114.968346] [5: kworker/5:2: 207] [TEST] mmc_sd_init_card: 1040: >> card->ocr 0x40000. >> [ 114.968359] [5: kworker/5:2: 207] [TEST] mmc_sd_get_cid: ocr >> 0x40000(pocr 0x40000), retries 10. >> [ 115.167346] [5: kworker/5:2: 207] [TEST] mmc_sd_init_card: 1119: >> caps=0x407f020f, sd3_bus_mode=0x3, v18_fixup_failed false, signal_voltage >> =0x1. >> [ 115.167366] [5: kworker/5:2: 207] [TEST] mmc_sd_init_card: 1149: rocr >> 0xc1ff8000, S18A, uhs. >> [ 115.168041] [5: kworker/5:2: 207] [TEST] mmc_sd_init_uhs_card: before >> update: caps 0x407f020f, sd3_bus_mode = 3, sd_bus_speed = 3, card->ocr = >> 0x40000. >> [ 115.168051] [5: kworker/5:2: 207] [TEST] sd_update_bus_speed_mode: >> caps 0x407f020f, sd3_bus_mode = 3, sd_bus_speed = 1, card->ocr = 0x40000. >> [ 115.169176] [5: kworker/5:2: 207] [TEST] sd_set_bus_speed_mode: >> sd_bus_speed=1, timing=4, uhs_max_dtr=50000000, card->ocr=0x40000. >> >> TO-BE : TEST log with this commit >> // resume : issue occurs : SDcard doesn't release busy for checking 10 >> times >> [ 1843.594805] [4: kworker/4:5:21512] [TEST] mmc_sd_get_cid: ocr >> 0x41040000(pocr 0x40000), retries 0. >> [ 1843.594812] [4: kworker/4:5:21512] mmc0: Skipping voltage switch >> [ 1843.772555] [4: kworker/4:5:21512] [TEST] mmc_sd_init_card: 1122: >> caps=0x407f020f, sd3_bus_mode=0x1f, v18_fixup_failed false, signal_voltage >> =0x0. >> // no update sd3_bus_mode value >> [ 1843.772563] [4: kworker/4:5:21512] [TEST] mmc_sd_init_card: 1164: >> switch hs. >> // next resume : the SDcard initializes to SDR104 >> [ 1844.191295] [5: kworker/5:93: 2282] [TEST] mmc_sd_init_card: 1122: >> caps=0x407f020f, sd3_bus_mode=0x1f, v18_fixup_failed false, signal_voltage >> =0x1. >> [ 1844.191315] [5: kworker/5:93: 2282] [TEST] mmc_sd_init_card: 1154: >> rocr 0xc1ff8000, S18A, uhs. >> [ 1844.192175] [5: kworker/5:93: 2282] [TEST] mmc_sd_init_uhs_card: >> before update: caps 0x407f020f, sd3_bus_mode = 0x1f, sd_bus_speed = 3, >> card->ocr = 0x40000. >> [ 1844.192187] [5: kworker/5:93: 2282] [TEST] sd_update_bus_speed_mode: >> caps 0x407f020f, sd3_bus_mode = 0x1f, sd_bus_speed = 3, card->ocr = >> 0x40000. >> [ 1844.198697] [5: kworker/5:93: 2282] [TEST] sd_set_bus_speed_mode: >> sd_bus_speed=3, timing=6, uhs_max_dtr=208000000, card->ocr=0x40000. >> >> Signed-off-by: Seunghui Lee <sh043.lee@xxxxxxxxxxx> >> Tested-by: DooHyun Hwang <dh0421.hwang@xxxxxxxxxxx> >> --- >> drivers/mmc/core/sd.c | 47 ++----------------------------------------- >> 1 file changed, 2 insertions(+), 45 deletions(-) >> >> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index >> cee4c0b59f43..4e3d39956185 100644 >> --- a/drivers/mmc/core/sd.c >> +++ b/drivers/mmc/core/sd.c >> @@ -1001,18 +1001,6 @@ unsigned mmc_sd_get_max_clock(struct mmc_card *card) >> return max_dtr; >> } >> >> -static bool mmc_sd_card_using_v18(struct mmc_card *card) -{ >> - /* >> - * According to the SD spec., the Bus Speed Mode (function group 1) >> bits >> - * 2 to 4 are zero if the card is initialized at 3.3V signal level. >> Thus >> - * they can be used to determine if the card has already switched >> to >> - * 1.8V signaling. >> - */ >> - return card->sw_caps.sd3_bus_mode & >> - (SD_MODE_UHS_SDR50 | SD_MODE_UHS_SDR104 | SD_MODE_UHS_DDR50); >> -} >> - >> static int sd_write_ext_reg(struct mmc_card *card, u8 fno, u8 page, u16 >> offset, >> u8 reg_data) >> { >> @@ -1400,10 +1388,9 @@ static int mmc_sd_init_card(struct mmc_host *host, >> u32 ocr, >> int err; >> u32 cid[4]; >> u32 rocr = 0; >> - bool v18_fixup_failed = false; >> >> WARN_ON(!host->claimed); >> -retry: >> + >> err = mmc_sd_get_cid(host, ocr, cid, &rocr); >> if (err) >> return err; >> @@ -1472,36 +1459,6 @@ static int mmc_sd_init_card(struct mmc_host *host, >> u32 ocr, >> if (err) >> goto free_card; >> >> - /* >> - * If the card has not been power cycled, it may still be using >> 1.8V >> - * signaling. Detect that situation and try to initialize a UHS-I >> (1.8V) >> - * transfer mode. >> - */ >> - if (!v18_fixup_failed && !mmc_host_is_spi(host) && >> mmc_host_uhs(host) && >> - mmc_sd_card_using_v18(card) && >> - host->ios.signal_voltage != MMC_SIGNAL_VOLTAGE_180) { >> - /* >> - * Re-read switch information in case it has changed since >> - * oldcard was initialized. >> - */ >> - if (oldcard) { >> - err = mmc_read_switch(card); >> - if (err) >> - goto free_card; >> - } >> - if (mmc_sd_card_using_v18(card)) { >> - if (mmc_host_set_uhs_voltage(host) || >> - mmc_sd_init_uhs_card(card)) { >> - v18_fixup_failed = true; >> - mmc_power_cycle(host, ocr); >> - if (!oldcard) >> - mmc_remove_card(card); >> - goto retry; >> - } >> - goto done; >> - } >> - } >> - >> /* Initialization sequence for UHS-I cards */ >> if (rocr & SD_ROCR_S18A && mmc_host_uhs(host)) { >> err = mmc_sd_init_uhs_card(card); >> @@ -1566,7 +1523,7 @@ static int mmc_sd_init_card(struct mmc_host *host, >> u32 ocr, >> err = -EINVAL; >> goto free_card; >> } >> -done: >> + >> host->card = card; >> return 0; >> >> -- >> 2.29.0 > > Dear All, > > Please review this commit. I have started to look at it, but my time is limited at the moment. Note the original patch is 5 years old and fixes a real problem, so we don't want to just throw it away. > > Once the SDR104 SD card fails to switch voltage, > there is no chance to work SDR104 bus speed again > due to update sd3_bus_mode. > > To fix this regression issue, do not update sd3_bus_mode. > And then it has the chance to work SDR104 again. > > AS-IS: > voltage_switch fail -> mmc_read_switch() -> HS mode > next system resume > voltage switch success -> SDR25 mode > > TO-BE: > Voltage switch fail -> HS mode > Next system resume > Voltage switch success -> SDR104 mode > > And plus, mmc_set_uhs_voltage() has power_cycle now. > It means that if voltage switch fails, > the card initializes 3.3V signal level. > > Regards, > Seunghui Lee. >
