From cf0f1454dae5d9fbebc0e212cdf0a2090f2e64a5 Mon Sep 17 00:00:00 2001 From: Ahmad Fatoum Date: Tue, 18 Apr 2023 11:30:38 +0200 Subject: mci: core: factor out MMC bus width selection for reuse Higher speed modes like DDR52 and HS200 can operate at both 8-bit and 4-bit bus widths. To make it easier to support these, split up mci_startup_mmc, so the refactored parts can be called with different timings later on. Signed-off-by: Ahmad Fatoum Link: https://lore.barebox.org/20230418093040.1865982-3-a.fatoum@pengutronix.de Signed-off-by: Sascha Hauer --- drivers/mci/mci-core.c | 95 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 64 insertions(+), 31 deletions(-) diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c index 2abed00117..bd5299e7a4 100644 --- a/drivers/mci/mci-core.c +++ b/drivers/mci/mci-core.c @@ -1167,34 +1167,51 @@ static int mci_startup_sd(struct mci *mci) return 0; } -static int mci_startup_mmc(struct mci *mci) +static u32 mci_bus_width_ext_csd_bits(enum mci_bus_width bus_width) +{ + switch (bus_width) { + case MMC_BUS_WIDTH_8: + return EXT_CSD_BUS_WIDTH_8; + case MMC_BUS_WIDTH_4: + return EXT_CSD_BUS_WIDTH_4; + case MMC_BUS_WIDTH_1: + default: + return EXT_CSD_BUS_WIDTH_1; + } +} + +static int mci_mmc_try_bus_width(struct mci *mci, enum mci_bus_width bus_width) { - struct mci_host *host = mci->host; + u32 ext_csd_bits; int err; + + ext_csd_bits = mci_bus_width_ext_csd_bits(bus_width); + + err = mci_switch(mci, EXT_CSD_BUS_WIDTH, ext_csd_bits); + if (err < 0) + return err; + + mci_set_bus_width(mci, bus_width); + + err = mmc_compare_ext_csds(mci, bus_width); + if (err < 0) + return err; + + return bus_width; +} + +static int mci_mmc_select_bus_width(struct mci *mci) +{ + struct mci_host *host = mci->host; + int ret; int idx = 0; - static unsigned ext_csd_bits[] = { - EXT_CSD_BUS_WIDTH_4, - EXT_CSD_BUS_WIDTH_8, - }; static enum mci_bus_width bus_widths[] = { MMC_BUS_WIDTH_4, MMC_BUS_WIDTH_8, }; - /* if possible, speed up the transfer */ - if (mci_caps(mci) & MMC_CAP_MMC_HIGHSPEED) { - if (mci->card_caps & MMC_CAP_MMC_HIGHSPEED_52MHZ) - mci->tran_speed = 52000000; - else - mci->tran_speed = 26000000; - - host->timing = MMC_TIMING_MMC_HS; - } - - mci_set_clock(mci, mci->tran_speed); - if (!(host->host_caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA))) - return 0; + return MMC_BUS_WIDTH_1; /* * Unlike SD, MMC cards dont have a configuration register to notify @@ -1206,7 +1223,6 @@ static int mci_startup_mmc(struct mci *mci) idx = 1; for (; idx >= 0; idx--) { - /* * Host is capable of 8bit transfer, then switch * the device to work in 8bit transfer mode. If the @@ -1214,21 +1230,38 @@ static int mci_startup_mmc(struct mci *mci) * 4bit transfer mode. On success set the corresponding * bus width on the host. */ - err = mci_switch(mci, EXT_CSD_BUS_WIDTH, ext_csd_bits[idx]); - if (err) { - if (idx == 0) - dev_warn(&mci->dev, "Changing MMC bus width failed: %d\n", err); - continue; - } + ret = mci_mmc_try_bus_width(mci, bus_widths[idx]); + if (ret > 0) + break; + } - mci_set_bus_width(mci, bus_widths[idx]); + return ret; +} - err = mmc_compare_ext_csds(mci, bus_widths[idx]); - if (!err) - break; +static int mci_startup_mmc(struct mci *mci) +{ + struct mci_host *host = mci->host; + int ret; + + /* if possible, speed up the transfer */ + if (mci_caps(mci) & MMC_CAP_MMC_HIGHSPEED) { + if (mci->card_caps & MMC_CAP_MMC_HIGHSPEED_52MHZ) + mci->tran_speed = 52000000; + else + mci->tran_speed = 26000000; + + host->timing = MMC_TIMING_MMC_HS; } - return err; + mci_set_clock(mci, mci->tran_speed); + + ret = mci_mmc_select_bus_width(mci); + if (ret < 0) { + dev_warn(&mci->dev, "Changing MMC bus width failed: %d\n", ret); + return ret; + } + + return 0; } /** -- cgit v1.2.1