From 0173055842cd1d9ed3984e70891c22dbf2f29372 Mon Sep 17 00:00:00 2001 From: Doug Anderson Date: Fri, 22 Aug 2014 19:17:51 +0530 Subject: [PATCH] mmc: dw_mmc: Support voltage changes For UHS cards we need the ability to switch voltages from 3.3V to 1.8V. Add support to the dw_mmc driver to handle this. Note that dw_mmc needs a little bit of extra code since the interface needs a special bit programmed to the CMD register while CMD11 is progressing. This means adding a few extra states to the state machine to track. Signed-off-by: Doug Anderson Signed-off-by: Yuvaraj Kumar C D Signed-off-by: Ulf Hansson --- drivers/mmc/host/dw_mmc.c | 137 ++++++++++++++++++++++++++++++++++--- drivers/mmc/host/dw_mmc.h | 5 +- include/linux/mmc/dw_mmc.h | 2 + 3 files changed, 134 insertions(+), 10 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index aadb0d6aa63f..23719249182b 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -234,10 +235,13 @@ err: } #endif /* defined(CONFIG_DEBUG_FS) */ +static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg); + static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd) { struct mmc_data *data; struct dw_mci_slot *slot = mmc_priv(mmc); + struct dw_mci *host = slot->host; const struct dw_mci_drv_data *drv_data = slot->host->drv_data; u32 cmdr; cmd->error = -EINPROGRESS; @@ -253,6 +257,34 @@ static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd) else if (cmd->opcode != MMC_SEND_STATUS && cmd->data) cmdr |= SDMMC_CMD_PRV_DAT_WAIT; + if (cmd->opcode == SD_SWITCH_VOLTAGE) { + u32 clk_en_a; + + /* Special bit makes CMD11 not die */ + cmdr |= SDMMC_CMD_VOLT_SWITCH; + + /* Change state to continue to handle CMD11 weirdness */ + WARN_ON(slot->host->state != STATE_SENDING_CMD); + slot->host->state = STATE_SENDING_CMD11; + + /* + * We need to disable low power mode (automatic clock stop) + * while doing voltage switch so we don't confuse the card, + * since stopping the clock is a specific part of the UHS + * voltage change dance. + * + * Note that low power mode (SDMMC_CLKEN_LOW_PWR) will be + * unconditionally turned back on in dw_mci_setup_bus() if it's + * ever called with a non-zero clock. That shouldn't happen + * until the voltage change is all done. + */ + clk_en_a = mci_readl(host, CLKENA); + clk_en_a &= ~(SDMMC_CLKEN_LOW_PWR << slot->id); + mci_writel(host, CLKENA, clk_en_a); + mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | + SDMMC_CMD_PRV_DAT_WAIT, 0); + } + if (cmd->flags & MMC_RSP_PRESENT) { /* We expect a response, so set this bit */ cmdr |= SDMMC_CMD_RESP_EXP; @@ -775,11 +807,15 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) unsigned int clock = slot->clock; u32 div; u32 clk_en_a; + u32 sdmmc_cmd_bits = SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT; + + /* We must continue to set bit 28 in CMD until the change is complete */ + if (host->state == STATE_WAITING_CMD11_DONE) + sdmmc_cmd_bits |= SDMMC_CMD_VOLT_SWITCH; if (!clock) { mci_writel(host, CLKENA, 0); - mci_send_cmd(slot, - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); + mci_send_cmd(slot, sdmmc_cmd_bits, 0); } else if (clock != host->current_speed || force_clkinit) { div = host->bus_hz / clock; if (host->bus_hz % clock && host->bus_hz > clock) @@ -803,15 +839,13 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) mci_writel(host, CLKSRC, 0); /* inform CIU */ - mci_send_cmd(slot, - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); + mci_send_cmd(slot, sdmmc_cmd_bits, 0); /* set clock to desired speed */ mci_writel(host, CLKDIV, div); /* inform CIU */ - mci_send_cmd(slot, - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); + mci_send_cmd(slot, sdmmc_cmd_bits, 0); /* enable clock; only low power if no SDIO */ clk_en_a = SDMMC_CLKEN_ENABLE << slot->id; @@ -820,8 +854,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) mci_writel(host, CLKENA, clk_en_a); /* inform CIU */ - mci_send_cmd(slot, - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); + mci_send_cmd(slot, sdmmc_cmd_bits, 0); /* keep the clock with reflecting clock dividor */ slot->__clk_old = clock << div; @@ -897,6 +930,17 @@ static void dw_mci_queue_request(struct dw_mci *host, struct dw_mci_slot *slot, slot->mrq = mrq; + if (host->state == STATE_WAITING_CMD11_DONE) { + dev_warn(&slot->mmc->class_dev, + "Voltage change didn't complete\n"); + /* + * this case isn't expected to happen, so we can + * either crash here or just try to continue on + * in the closest possible state + */ + host->state = STATE_IDLE; + } + if (host->state == STATE_IDLE) { host->state = STATE_SENDING_CMD; dw_mci_start_request(host, slot); @@ -973,6 +1017,9 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) /* Slot specific timing and width adjustment */ dw_mci_setup_bus(slot, false); + if (slot->host->state == STATE_WAITING_CMD11_DONE && ios->clock != 0) + slot->host->state = STATE_IDLE; + switch (ios->power_mode) { case MMC_POWER_UP: if (!IS_ERR(mmc->supply.vmmc)) { @@ -1016,6 +1063,59 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) } } +static int dw_mci_card_busy(struct mmc_host *mmc) +{ + struct dw_mci_slot *slot = mmc_priv(mmc); + u32 status; + + /* + * Check the busy bit which is low when DAT[3:0] + * (the data lines) are 0000 + */ + status = mci_readl(slot->host, STATUS); + + return !!(status & SDMMC_STATUS_BUSY); +} + +static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios) +{ + struct dw_mci_slot *slot = mmc_priv(mmc); + struct dw_mci *host = slot->host; + u32 uhs; + u32 v18 = SDMMC_UHS_18V << slot->id; + int min_uv, max_uv; + int ret; + + /* + * Program the voltage. Note that some instances of dw_mmc may use + * the UHS_REG for this. For other instances (like exynos) the UHS_REG + * does no harm but you need to set the regulator directly. Try both. + */ + uhs = mci_readl(host, UHS_REG); + if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330) { + min_uv = 2700000; + max_uv = 3600000; + uhs &= ~v18; + } else { + min_uv = 1700000; + max_uv = 1950000; + uhs |= v18; + } + if (!IS_ERR(mmc->supply.vqmmc)) { + ret = regulator_set_voltage(mmc->supply.vqmmc, min_uv, max_uv); + + if (ret) { + dev_err(&mmc->class_dev, + "Regulator set error %d: %d - %d\n", + ret, min_uv, max_uv); + return ret; + } + } + mci_writel(host, UHS_REG, uhs); + + return 0; +} + static int dw_mci_get_ro(struct mmc_host *mmc) { int read_only; @@ -1158,6 +1258,9 @@ static const struct mmc_host_ops dw_mci_ops = { .get_cd = dw_mci_get_cd, .enable_sdio_irq = dw_mci_enable_sdio_irq, .execute_tuning = dw_mci_execute_tuning, + .card_busy = dw_mci_card_busy, + .start_signal_voltage_switch = dw_mci_switch_voltage, + }; static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq) @@ -1181,7 +1284,11 @@ static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq) dw_mci_start_request(host, slot); } else { dev_vdbg(host->dev, "list empty\n"); - host->state = STATE_IDLE; + + if (host->state == STATE_SENDING_CMD11) + host->state = STATE_WAITING_CMD11_DONE; + else + host->state = STATE_IDLE; } spin_unlock(&host->lock); @@ -1292,8 +1399,10 @@ static void dw_mci_tasklet_func(unsigned long priv) switch (state) { case STATE_IDLE: + case STATE_WAITING_CMD11_DONE: break; + case STATE_SENDING_CMD11: case STATE_SENDING_CMD: if (!test_and_clear_bit(EVENT_CMD_COMPLETE, &host->pending_events)) @@ -1894,6 +2003,14 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) } if (pending) { + /* Check volt switch first, since it can look like an error */ + if ((host->state == STATE_SENDING_CMD11) && + (pending & SDMMC_INT_VOLT_SWITCH)) { + mci_writel(host, RINTSTS, SDMMC_INT_VOLT_SWITCH); + pending &= ~SDMMC_INT_VOLT_SWITCH; + dw_mci_cmd_interrupt(host, pending); + } + if (pending & DW_MCI_CMD_ERROR_FLAGS) { mci_writel(host, RINTSTS, DW_MCI_CMD_ERROR_FLAGS); host->cmd_status = pending; @@ -1999,7 +2116,9 @@ static void dw_mci_work_routine_card(struct work_struct *work) switch (host->state) { case STATE_IDLE: + case STATE_WAITING_CMD11_DONE: break; + case STATE_SENDING_CMD11: case STATE_SENDING_CMD: mrq->cmd->error = -ENOMEDIUM; if (!mrq->data) diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h index 08fd956d81f3..01b99e8a9190 100644 --- a/drivers/mmc/host/dw_mmc.h +++ b/drivers/mmc/host/dw_mmc.h @@ -99,6 +99,7 @@ #define SDMMC_INT_HLE BIT(12) #define SDMMC_INT_FRUN BIT(11) #define SDMMC_INT_HTO BIT(10) +#define SDMMC_INT_VOLT_SWITCH BIT(10) /* overloads bit 10! */ #define SDMMC_INT_DRTO BIT(9) #define SDMMC_INT_RTO BIT(8) #define SDMMC_INT_DCRC BIT(7) @@ -113,6 +114,7 @@ /* Command register defines */ #define SDMMC_CMD_START BIT(31) #define SDMMC_CMD_USE_HOLD_REG BIT(29) +#define SDMMC_CMD_VOLT_SWITCH BIT(28) #define SDMMC_CMD_CCS_EXP BIT(23) #define SDMMC_CMD_CEATA_RD BIT(22) #define SDMMC_CMD_UPD_CLK BIT(21) @@ -130,6 +132,7 @@ /* Status register defines */ #define SDMMC_GET_FCNT(x) (((x)>>17) & 0x1FFF) #define SDMMC_STATUS_DMA_REQ BIT(31) +#define SDMMC_STATUS_BUSY BIT(9) /* FIFOTH register defines */ #define SDMMC_SET_FIFOTH(m, r, t) (((m) & 0x7) << 28 | \ ((r) & 0xFFF) << 16 | \ @@ -150,7 +153,7 @@ #define SDMMC_GET_VERID(x) ((x) & 0xFFFF) /* Card read threshold */ #define SDMMC_SET_RD_THLD(v, x) (((v) & 0x1FFF) << 16 | (x)) - +#define SDMMC_UHS_18V BIT(0) /* All ctrl reset bits */ #define SDMMC_CTRL_ALL_RESET_FLAGS \ (SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET | SDMMC_CTRL_DMA_RESET) diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h index 84e2827d0f0b..001366927cf4 100644 --- a/include/linux/mmc/dw_mmc.h +++ b/include/linux/mmc/dw_mmc.h @@ -26,6 +26,8 @@ enum dw_mci_state { STATE_DATA_BUSY, STATE_SENDING_STOP, STATE_DATA_ERROR, + STATE_SENDING_CMD11, + STATE_WAITING_CMD11_DONE, }; enum { -- 2.20.1