renesas_sdhi_core.c

/*
 * Renesas SDHI
 *
 * Copyright (C) 2016 Sang Engineering, Wolfram Sang
 * Copyright (C) 2015-16 Renesas Electronics Corporation
 * Copyright (C) 2009 Magnus Damm
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Based on "Compaq ASIC3 support":
 *
 * Copyright 2001 Compaq Computer Corporation.
 * Copyright 2004-2005 Phil Blundell
 * Copyright 2007-2008 OpenedHand Ltd.
 *
 * Authors: Phil Blundell <pb@handhelds.org>,
 *	    Samuel Ortiz <sameo@openedhand.com>
 *
 */

#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/mmc/host.h>
#include <linux/mfd/tmio.h>
#include <linux/sh_dma.h>
#include <linux/delay.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pinctrl/pinctrl-state.h>
#include <linux/regulator/consumer.h>

#include "renesas_sdhi.h"
#include "tmio_mmc.h"

#define EXT_ACC           0xe4

#define SDHI_VER_GEN2_SDR50	0x490c
/* very old datasheets said 0x490c for SDR104, too. They are wrong! */
#define SDHI_VER_GEN2_SDR104	0xcb0d
#define SDHI_VER_GEN3_SD	0xcc10
#define SDHI_VER_GEN3_SDMMC	0xcd10

#define host_to_priv(host) container_of((host)->pdata, struct renesas_sdhi, mmc_data)

struct renesas_sdhi {
	struct clk *clk;
	struct clk *clk_cd;
	struct tmio_mmc_data mmc_data;
	struct tmio_mmc_dma dma_priv;
	struct pinctrl *pinctrl;
	struct pinctrl_state *pins_default, *pins_uhs;
	void __iomem *scc_ctl;
};

static void renesas_sdhi_sdbuf_width(struct tmio_mmc_host *host, int width)
{
	u32 val;

	/*
	 * see also
	 *	renesas_sdhi_of_data :: dma_buswidth
	 */
	switch (sd_ctrl_read16(host, CTL_VERSION)) {
	case SDHI_VER_GEN2_SDR50:
		val = (width == 32) ? 0x0001 : 0x0000;
		break;
	case SDHI_VER_GEN2_SDR104:
		val = (width == 32) ? 0x0000 : 0x0001;
		break;
	case SDHI_VER_GEN3_SD:
	case SDHI_VER_GEN3_SDMMC:
		if (width == 64)
			val = 0x0000;
		else if (width == 32)
			val = 0x0101;
		else
			val = 0x0001;
		break;
	default:
		/* nothing to do */
		return;
	}

	sd_ctrl_write16(host, EXT_ACC, val);
}

static int renesas_sdhi_clk_enable(struct tmio_mmc_host *host)
{
	struct mmc_host *mmc = host->mmc;
	struct renesas_sdhi *priv = host_to_priv(host);
	int ret = clk_prepare_enable(priv->clk);
	if (ret < 0)
		return ret;

	ret = clk_prepare_enable(priv->clk_cd);
	if (ret < 0) {
		clk_disable_unprepare(priv->clk);
		return ret;
	}

	/*
	 * The clock driver may not know what maximum frequency
	 * actually works, so it should be set with the max-frequency
	 * property which will already have been read to f_max.  If it
	 * was missing, assume the current frequency is the maximum.
	 */
	if (!mmc->f_max)
		mmc->f_max = clk_get_rate(priv->clk);

	/*
	 * Minimum frequency is the minimum input clock frequency
	 * divided by our maximum divider.
	 */
	mmc->f_min = max(clk_round_rate(priv->clk, 1) / 512, 1L);

	/* enable 16bit data access on SDBUF as default */
	renesas_sdhi_sdbuf_width(host, 16);

	return 0;
}

static unsigned int renesas_sdhi_clk_update(struct tmio_mmc_host *host,
					      unsigned int new_clock)
{
	struct renesas_sdhi *priv = host_to_priv(host);
	unsigned int freq, diff, best_freq = 0, diff_min = ~0;
	int i, ret;

	/* tested only on RCar Gen2+ currently; may work for others */
	if (!(host->pdata->flags & TMIO_MMC_MIN_RCAR2))
		return clk_get_rate(priv->clk);

	/*
	 * We want the bus clock to be as close as possible to, but no
	 * greater than, new_clock.  As we can divide by 1 << i for
	 * any i in [0, 9] we want the input clock to be as close as
	 * possible, but no greater than, new_clock << i.
	 */
	for (i = min(9, ilog2(UINT_MAX / new_clock)); i >= 0; i--) {
		freq = clk_round_rate(priv->clk, new_clock << i);
		if (freq > (new_clock << i)) {
			/* Too fast; look for a slightly slower option */
			freq = clk_round_rate(priv->clk,
					      (new_clock << i) / 4 * 3);
			if (freq > (new_clock << i))
				continue;
		}

		diff = new_clock - (freq >> i);
		if (diff <= diff_min) {
			best_freq = freq;
			diff_min = diff;
		}
	}

	ret = clk_set_rate(priv->clk, best_freq);

	return ret == 0 ? best_freq : clk_get_rate(priv->clk);
}

static void renesas_sdhi_clk_disable(struct tmio_mmc_host *host)
{
	struct renesas_sdhi *priv = host_to_priv(host);

	clk_disable_unprepare(priv->clk);
	clk_disable_unprepare(priv->clk_cd);
}

static int renesas_sdhi_card_busy(struct mmc_host *mmc)
{
	struct tmio_mmc_host *host = mmc_priv(mmc);

	return !(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS) & TMIO_STAT_DAT0);
}

static int renesas_sdhi_start_signal_voltage_switch(struct mmc_host *mmc,
						      struct mmc_ios *ios)
{
	struct tmio_mmc_host *host = mmc_priv(mmc);
	struct renesas_sdhi *priv = host_to_priv(host);
	struct pinctrl_state *pin_state;
	int ret;

	switch (ios->signal_voltage) {
	case MMC_SIGNAL_VOLTAGE_330:
		pin_state = priv->pins_default;
		break;
	case MMC_SIGNAL_VOLTAGE_180:
		pin_state = priv->pins_uhs;
		break;
	default:
		return -EINVAL;
	}

	/*
	 * If anything is missing, assume signal voltage is fixed at
	 * 3.3V and succeed/fail accordingly.
	 */
	if (IS_ERR(priv->pinctrl) || IS_ERR(pin_state))
		return ios->signal_voltage ==
			MMC_SIGNAL_VOLTAGE_330 ? 0 : -EINVAL;

	ret = mmc_regulator_set_vqmmc(host->mmc, ios);
	if (ret)
		return ret;

	return pinctrl_select_state(priv->pinctrl, pin_state);
}

/* SCC registers */
#define SH_MOBILE_SDHI_SCC_DTCNTL	0x000
#define SH_MOBILE_SDHI_SCC_TAPSET	0x002
#define SH_MOBILE_SDHI_SCC_DT2FF	0x004
#define SH_MOBILE_SDHI_SCC_CKSEL	0x006
#define SH_MOBILE_SDHI_SCC_RVSCNTL	0x008
#define SH_MOBILE_SDHI_SCC_RVSREQ	0x00A

/* Definitions for values the SH_MOBILE_SDHI_SCC_DTCNTL register */
#define SH_MOBILE_SDHI_SCC_DTCNTL_TAPEN		BIT(0)
#define SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT	16
#define SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_MASK	0xff

/* Definitions for values the SH_MOBILE_SDHI_SCC_CKSEL register */
#define SH_MOBILE_SDHI_SCC_CKSEL_DTSEL		BIT(0)
/* Definitions for values the SH_MOBILE_SDHI_SCC_RVSCNTL register */
#define SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN	BIT(0)
/* Definitions for values the SH_MOBILE_SDHI_SCC_RVSREQ register */
#define SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR	BIT(2)

static inline u32 sd_scc_read32(struct tmio_mmc_host *host,
				struct renesas_sdhi *priv, int addr)
{
	return readl(priv->scc_ctl + (addr << host->bus_shift));
}

static inline void sd_scc_write32(struct tmio_mmc_host *host,
				  struct renesas_sdhi *priv,
				  int addr, u32 val)
{
	writel(val, priv->scc_ctl + (addr << host->bus_shift));
}

static unsigned int renesas_sdhi_init_tuning(struct tmio_mmc_host *host)
{
	struct renesas_sdhi *priv;

	priv = host_to_priv(host);

	/* set sampling clock selection range */
	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL,
		       0x8 << SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT);

	/* Initialize SCC */
	sd_ctrl_write32_as_16_and_16(host, CTL_STATUS, 0x0);

	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL,
		       SH_MOBILE_SDHI_SCC_DTCNTL_TAPEN |
		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL));

	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
			sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));

	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL,
		       SH_MOBILE_SDHI_SCC_CKSEL_DTSEL |
		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL));

	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
			sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));

	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
		       ~SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &
		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));

	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DT2FF, host->scc_tappos);

	/* Read TAPNUM */
	return (sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL) >>
		SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT) &
		SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_MASK;
}

static void renesas_sdhi_prepare_tuning(struct tmio_mmc_host *host,
					 unsigned long tap)
{
	struct renesas_sdhi *priv = host_to_priv(host);

	/* Set sampling clock position */
	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, tap);
}

#define SH_MOBILE_SDHI_MAX_TAP 3

static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
{
	struct renesas_sdhi *priv = host_to_priv(host);
	unsigned long tap_cnt;  /* counter of tuning success */
	unsigned long tap_set;  /* tap position */
	unsigned long tap_start;/* start position of tuning success */
	unsigned long tap_end;  /* end position of tuning success */
	unsigned long ntap;     /* temporary counter of tuning success */
	unsigned long i;

	/* Clear SCC_RVSREQ */
	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);

	/*
	 * Find the longest consecutive run of successful probes.  If that
	 * is more than SH_MOBILE_SDHI_MAX_TAP probes long then use the
	 * center index as the tap.
	 */
	tap_cnt = 0;
	ntap = 0;
	tap_start = 0;
	tap_end = 0;
	for (i = 0; i < host->tap_num * 2; i++) {
		if (test_bit(i, host->taps))
			ntap++;
		else {
			if (ntap > tap_cnt) {
				tap_start = i - ntap;
				tap_end = i - 1;
				tap_cnt = ntap;
			}
			ntap = 0;
		}
	}

	if (ntap > tap_cnt) {
		tap_start = i - ntap;
		tap_end = i - 1;
		tap_cnt = ntap;
	}

	if (tap_cnt >= SH_MOBILE_SDHI_MAX_TAP)
		tap_set = (tap_start + tap_end) / 2 % host->tap_num;
	else
		return -EIO;

	/* Set SCC */
	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, tap_set);

	/* Enable auto re-tuning */
	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
		       SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN |
		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));

	return 0;
}


static bool renesas_sdhi_check_scc_error(struct tmio_mmc_host *host)
{
	struct renesas_sdhi *priv = host_to_priv(host);

	/* Check SCC error */
	if (sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL) &
	    SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &&
	    sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ) &
	    SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR) {
		/* Clear SCC error */
		sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
		return true;
	}

	return false;
}

static void renesas_sdhi_hw_reset(struct tmio_mmc_host *host)
{
	struct renesas_sdhi *priv;

	priv = host_to_priv(host);

	/* Reset SCC */
	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
			sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));

	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL,
		       ~SH_MOBILE_SDHI_SCC_CKSEL_DTSEL &
		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL));

	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
			sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));

	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
		       ~SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &
		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));

	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
		       ~SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &
		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
}

static int renesas_sdhi_wait_idle(struct tmio_mmc_host *host)
{
	int timeout = 1000;

	while (--timeout && !(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS)
			      & TMIO_STAT_SCLKDIVEN))
		udelay(1);

	if (!timeout) {
		dev_warn(&host->pdev->dev, "timeout waiting for SD bus idle\n");
		return -EBUSY;
	}

	return 0;
}

static int renesas_sdhi_write16_hook(struct tmio_mmc_host *host, int addr)
{
	switch (addr)
	{
	case CTL_SD_CMD:
	case CTL_STOP_INTERNAL_ACTION:
	case CTL_XFER_BLK_COUNT:
	case CTL_SD_CARD_CLK_CTL:
	case CTL_SD_XFER_LEN:
	case CTL_SD_MEM_CARD_OPT:
	case CTL_TRANSACTION_CTL:
	case CTL_DMA_ENABLE:
	case EXT_ACC:
		return renesas_sdhi_wait_idle(host);
	}

	return 0;
}

static int renesas_sdhi_multi_io_quirk(struct mmc_card *card,
					 unsigned int direction, int blk_size)
{
	/*
	 * In Renesas controllers, when performing a
	 * multiple block read of one or two blocks,
	 * depending on the timing with which the
	 * response register is read, the response
	 * value may not be read properly.
	 * Use single block read for this HW bug
	 */
	if ((direction == MMC_DATA_READ) &&
	    blk_size == 2)
		return 1;

	return blk_size;
}

static void renesas_sdhi_enable_dma(struct tmio_mmc_host *host, bool enable)
{
	sd_ctrl_write16(host, CTL_DMA_ENABLE, enable ? 2 : 0);

	/* enable 32bit access if DMA mode if possibile */
	renesas_sdhi_sdbuf_width(host, enable ? 32 : 16);
}

int renesas_sdhi_probe(struct platform_device *pdev,
		       const struct tmio_mmc_dma_ops *dma_ops)
{
	const struct renesas_sdhi_of_data *of_data = of_device_get_match_data( &pdev->dev);
	struct renesas_sdhi *priv;
	struct tmio_mmc_data *mmc_data;
	struct tmio_mmc_data *mmd = pdev->dev.platform_data;
	struct tmio_mmc_host *host;
	struct resource *res;
	int irq, ret, i;
	struct tmio_mmc_dma *dma_priv;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -EINVAL;

	priv = devm_kzalloc(&pdev->dev, sizeof(struct renesas_sdhi), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	mmc_data = &priv->mmc_data;
	dma_priv = &priv->dma_priv;

	priv->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(priv->clk)) {
		ret = PTR_ERR(priv->clk);
		dev_err(&pdev->dev, "cannot get clock: %d\n", ret);
		goto eprobe;
	}

	/*
	 * Some controllers provide a 2nd clock just to run the internal card
	 * detection logic. Unfortunately, the existing driver architecture does
	 * not support a separation of clocks for runtime PM usage. When
	 * native hotplug is used, the tmio driver assumes that the core
	 * must continue to run for card detect to stay active, so we cannot
	 * disable it.
	 * Additionally, it is prohibited to supply a clock to the core but not
	 * to the card detect circuit. That leaves us with if separate clocks
	 * are presented, we must treat them both as virtually 1 clock.
	 */
	priv->clk_cd = devm_clk_get(&pdev->dev, "cd");
	if (IS_ERR(priv->clk_cd))
		priv->clk_cd = NULL;

	priv->pinctrl = devm_pinctrl_get(&pdev->dev);
	if (!IS_ERR(priv->pinctrl)) {
		priv->pins_default = pinctrl_lookup_state(priv->pinctrl,
						PINCTRL_STATE_DEFAULT);
		priv->pins_uhs = pinctrl_lookup_state(priv->pinctrl,
						"state_uhs");
	}

	host = tmio_mmc_host_alloc(pdev);
	if (!host) {
		ret = -ENOMEM;
		goto eprobe;
	}


	if (of_data) {
		mmc_data->flags |= of_data->tmio_flags;
		mmc_data->ocr_mask = of_data->tmio_ocr_mask;
		mmc_data->capabilities |= of_data->capabilities;
		mmc_data->capabilities2 |= of_data->capabilities2;
		mmc_data->dma_rx_offset = of_data->dma_rx_offset;
		dma_priv->dma_buswidth = of_data->dma_buswidth;
		host->bus_shift = of_data->bus_shift;
	}

	host->dma		= dma_priv;
	host->write16_hook	= renesas_sdhi_write16_hook;
	host->clk_enable	= renesas_sdhi_clk_enable;
	host->clk_update	= renesas_sdhi_clk_update;
	host->clk_disable	= renesas_sdhi_clk_disable;
	host->multi_io_quirk	= renesas_sdhi_multi_io_quirk;

	/* SDR speeds are only available on Gen2+ */
	if (mmc_data->flags & TMIO_MMC_MIN_RCAR2) {
		/* card_busy caused issues on r8a73a4 (pre-Gen2) CD-less SDHI */
		host->card_busy	= renesas_sdhi_card_busy;
		host->start_signal_voltage_switch =
			renesas_sdhi_start_signal_voltage_switch;
	}

	/* Orginally registers were 16 bit apart, could be 32 or 64 nowadays */
	if (!host->bus_shift && resource_size(res) > 0x100) /* old way to determine the shift */
		host->bus_shift = 1;

	if (mmd)
		*mmc_data = *mmd;

	dma_priv->filter = shdma_chan_filter;
	dma_priv->enable = renesas_sdhi_enable_dma;

	mmc_data->alignment_shift = 1; /* 2-byte alignment */
	mmc_data->capabilities |= MMC_CAP_MMC_HIGHSPEED;

	/*
	 * All SDHI blocks support 2-byte and larger block sizes in 4-bit
	 * bus width mode.
	 */
	mmc_data->flags |= TMIO_MMC_BLKSZ_2BYTES;

	/*
	 * All SDHI blocks support SDIO IRQ signalling.
	 */
	mmc_data->flags |= TMIO_MMC_SDIO_IRQ;

	/*
	 * All SDHI have CMD12 controll bit
	 */
	mmc_data->flags |= TMIO_MMC_HAVE_CMD12_CTRL;

	/* All SDHI have SDIO status bits which must be 1 */
	mmc_data->flags |= TMIO_MMC_SDIO_STATUS_SETBITS;

	ret = tmio_mmc_host_probe(host, mmc_data, dma_ops);
	if (ret < 0)
		goto efree;

	/* Enable tuning iff we have an SCC and a supported mode */
	if (of_data && of_data->scc_offset &&
	    (host->mmc->caps & MMC_CAP_UHS_SDR104 ||
	     host->mmc->caps2 & MMC_CAP2_HS200_1_8V_SDR)) {
		const struct renesas_sdhi_scc *taps = of_data->taps;
		bool hit = false;

		host->mmc->caps |= MMC_CAP_HW_RESET;

		for (i = 0; i < of_data->taps_num; i++) {
			if (taps[i].clk_rate == 0 ||
			    taps[i].clk_rate == host->mmc->f_max) {
				host->scc_tappos = taps->tap;
				hit = true;
				break;
			}
		}

		if (!hit)
			dev_warn(&host->pdev->dev, "Unknown clock rate for SDR104\n");

		priv->scc_ctl = host->ctl + of_data->scc_offset;
		host->init_tuning = renesas_sdhi_init_tuning;
		host->prepare_tuning = renesas_sdhi_prepare_tuning;
		host->select_tuning = renesas_sdhi_select_tuning;
		host->check_scc_error = renesas_sdhi_check_scc_error;
		host->hw_reset = renesas_sdhi_hw_reset;
	}

	i = 0;
	while (1) {
		irq = platform_get_irq(pdev, i);
		if (irq < 0)
			break;
		i++;
		ret = devm_request_irq(&pdev->dev, irq, tmio_mmc_irq, 0,
				  dev_name(&pdev->dev), host);
		if (ret)
			goto eirq;
	}

	/* There must be at least one IRQ source */
	if (!i) {
		ret = irq;
		goto eirq;
	}

	dev_info(&pdev->dev, "%s base at 0x%08lx max clock rate %u MHz\n",
		 mmc_hostname(host->mmc), (unsigned long)
		 (platform_get_resource(pdev, IORESOURCE_MEM, 0)->start),
		 host->mmc->f_max / 1000000);

	return ret;

eirq:
	tmio_mmc_host_remove(host);
efree:
	tmio_mmc_host_free(host);
eprobe:
	return ret;
}
EXPORT_SYMBOL_GPL(renesas_sdhi_probe);

int renesas_sdhi_remove(struct platform_device *pdev)
{
	struct mmc_host *mmc = platform_get_drvdata(pdev);
	struct tmio_mmc_host *host = mmc_priv(mmc);

	tmio_mmc_host_remove(host);

	return 0;
}
EXPORT_SYMBOL_GPL(renesas_sdhi_remove);