> -----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. 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.
