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Subject[PATCH 18/19] mmc: mmci: add specific clk/pwr procedure for stm32 sdmmc
Date
From: Ludovic Barre <ludovic.barre@st.com>

This patch adds specific clock and power ios for stm32 sdmmc variant.
power ios: stm32 dedicated procedure must be done to perform power
off/on procedures. To power off, the sdmmc must be reset and set
to power cycle state before to disabling vqmmc. This drives low
SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK to prevent the Card from
being supplied through the signal lines.
To power on, set the SDMMC in power-off SDMMC_D[7:0], SDMMC_CMD
and SDMMC_CK are driven high. Then we can set the SDMMC to
Power-on state.

clock ios: specific bits behavior:
-clock divider card_clk = mclk / (2 * clkdiv)
-ddr activation
-wide bus 1/4/8bits
-bus speed
-receive clock selection (in_ck/ck_in/fb_ck)

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
drivers/mmc/host/mmci.c | 112 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 112 insertions(+)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 86aef4f..af27a0a 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -50,6 +50,10 @@

static unsigned int fmax = 515633;

+static void mmci_sdmmc_set_pwrreg(struct mmci_host *host,
+ unsigned char power_mode, unsigned int pwr);
+static void mmci_sdmmc_set_clkreg(struct mmci_host *host, unsigned int desired);
+
static struct variant_data variant_arm = {
.fifosize = 16 * 4,
.fifohalfsize = 8 * 4,
@@ -490,6 +494,114 @@ static void mmci_set_pwrreg(struct mmci_host *host, unsigned char power_mode,
mmci_write_pwrreg(host, pwr);
}

+static void mmci_sdmmc_set_clkreg(struct mmci_host *host, unsigned int desired)
+{
+ unsigned int clk = 0, ddr = 0;
+
+ if (host->mmc->ios.timing == MMC_TIMING_MMC_DDR52 ||
+ host->mmc->ios.timing == MMC_TIMING_UHS_DDR50)
+ ddr = MCI_STM32_CLK_DDR;
+
+ /*
+ * cclk = mclk / (2 * clkdiv)
+ * clkdiv 0 => bypass
+ * in ddr mode bypass is not possible
+ */
+ if (desired) {
+ if (desired >= host->mclk && !ddr) {
+ host->cclk = host->mclk;
+ } else {
+ clk = DIV_ROUND_UP(host->mclk, 2 * desired);
+ if (clk > MCI_STM32_CLK_CLKDIV_MSK)
+ clk = MCI_STM32_CLK_CLKDIV_MSK;
+ host->cclk = host->mclk / (2 * clk);
+ }
+ }
+
+ if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_4)
+ clk |= MCI_STM32_CLK_WIDEBUS_4;
+ if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_8)
+ clk |= MCI_STM32_CLK_WIDEBUS_8;
+
+ clk |= MCI_STM32_CLK_HWFCEN;
+ clk |= host->clk_reg_add;
+ clk |= ddr;
+
+ /*
+ * SDMMC_FBCK is selected when an external Delay Block is needed
+ * with SDR104.
+ */
+ if (host->mmc->ios.timing >= MMC_TIMING_UHS_SDR50) {
+ clk |= MCI_STM32_CLK_BUSSPEED;
+ if (host->mmc->ios.timing == MMC_TIMING_UHS_SDR104) {
+ clk &= ~MCI_STM32_CLK_SEL_MSK;
+ clk |= MCI_STM32_CLK_SELFBCK;
+ }
+ }
+
+ mmci_write_clkreg(host, clk);
+}
+
+static void mmci_sdmmc_set_pwrreg(struct mmci_host *host,
+ unsigned char power_mode, unsigned int pwr)
+{
+ struct mmc_host *mmc = host->mmc;
+
+ pwr |= host->pwr_reg_add;
+
+ switch (power_mode) {
+ case MMC_POWER_OFF:
+ if (!IS_ERR(mmc->supply.vmmc))
+ mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
+
+ /* Only a reset could disable sdmmc */
+ reset_control_assert(host->rst);
+ udelay(2);
+ reset_control_deassert(host->rst);
+
+ /* default mask (probe) must be activated */
+ writel(MCI_IRQENABLE | host->variant->start_err,
+ host->base + MMCIMASK0);
+
+ /*
+ * Set the SDMMC in Power-cycle state before to disabling vqmmc.
+ * This will make that the SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK
+ * are driven low, to prevent the Card from being supplied
+ * through the signal lines.
+ */
+ mmci_write_pwrreg(host, MCI_STM32_PWR_CYC | pwr);
+
+ if (!IS_ERR(host->mmc->supply.vqmmc) && host->vqmmc_enabled) {
+ regulator_disable(host->mmc->supply.vqmmc);
+ host->vqmmc_enabled = false;
+ }
+ break;
+ case MMC_POWER_UP:
+ if (!IS_ERR(mmc->supply.vmmc))
+ mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,
+ mmc->ios.vdd);
+ break;
+ case MMC_POWER_ON:
+ if (!IS_ERR(host->mmc->supply.vqmmc) && !host->vqmmc_enabled) {
+ if (regulator_enable(host->mmc->supply.vqmmc) < 0)
+ dev_err(mmc_dev(host->mmc),
+ "failed to enable vqmmc regulator\n");
+ else
+ host->vqmmc_enabled = true;
+ }
+
+ /*
+ * After a power-cycle state, we must set the SDMMC in
+ * Power-off. The SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK are
+ * driven high. Then we can set the SDMMC to Power-on state
+ */
+ mmci_write_pwrreg(host, MCI_PWR_OFF | pwr);
+ mdelay(1);
+ mmci_write_pwrreg(host, MCI_PWR_ON | pwr);
+ break;
+ }
+}
+
static void
mmci_request_end(struct mmci_host *host, struct mmc_request *mrq)
{
--
2.7.4
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