Commit 0f201655 authored by Adrian Hunter's avatar Adrian Hunter Committed by Chris Ball
Browse files

mmc: sdhci-pci: add eMMC hardware reset support 



Implement eMMC hardware reset for Medfield.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 20758b66

drivers/mmc/host/sdhci-pci.c

+72 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#include <linux/mmc/host.h>

#include <linux/scatterlist.h>

#include <linux/io.h>

#include <linux/gpio.h>

#include <linux/sfi.h>



#include "sdhci.h"
@@ -59,6 +61,7 @@ struct sdhci_pci_slot { 
	struct sdhci_host	*host;



	int			pci_bar;

	int			rst_n_gpio;

};



struct sdhci_pci_chip {
@@ -163,12 +166,63 @@ static int mrst_hc_probe(struct sdhci_pci_chip *chip) 
	return 0;

}



/* Medfield eMMC hardware reset GPIOs */

static int mfd_emmc0_rst_gpio = -EINVAL;

static int mfd_emmc1_rst_gpio = -EINVAL;



static int mfd_emmc_gpio_parse(struct sfi_table_header *table)

{

	struct sfi_table_simple *sb = (struct sfi_table_simple *)table;

	struct sfi_gpio_table_entry *entry;

	int i, num;



	num = SFI_GET_NUM_ENTRIES(sb, struct sfi_gpio_table_entry);

	entry = (struct sfi_gpio_table_entry *)sb->pentry;



	for (i = 0; i < num; i++, entry++) {

		if (!strncmp(entry->pin_name, "emmc0_rst", SFI_NAME_LEN))

			mfd_emmc0_rst_gpio = entry->pin_no;

		else if (!strncmp(entry->pin_name, "emmc1_rst", SFI_NAME_LEN))

			mfd_emmc1_rst_gpio = entry->pin_no;

	}



	return 0;

}



static int mfd_emmc_probe_slot(struct sdhci_pci_slot *slot)

{

	const char *name = NULL;

	int gpio = -EINVAL;



	sfi_table_parse(SFI_SIG_GPIO, NULL, NULL, mfd_emmc_gpio_parse);



	switch (slot->chip->pdev->device) {

	case PCI_DEVICE_ID_INTEL_MFD_EMMC0:

		gpio = mfd_emmc0_rst_gpio;

		name = "eMMC0_reset";

		break;

	case PCI_DEVICE_ID_INTEL_MFD_EMMC1:

		gpio = mfd_emmc1_rst_gpio;

		name = "eMMC1_reset";

		break;

	}



	if (!gpio_request(gpio, name)) {

		gpio_direction_output(gpio, 1);

		slot->rst_n_gpio = gpio;

		slot->host->mmc->caps |= MMC_CAP_HW_RESET;

	}



	slot->host->mmc->caps |= MMC_CAP_8_BIT_DATA;



	return 0;

}



static void mfd_emmc_remove_slot(struct sdhci_pci_slot *slot, int dead)

{

	gpio_free(slot->rst_n_gpio);

}



static const struct sdhci_pci_fixes sdhci_intel_mrst_hc0 = {

	.quirks		= SDHCI_QUIRK_BROKEN_ADMA | SDHCI_QUIRK_NO_HISPD_BIT,

	.probe_slot	= mrst_hc_probe_slot,
@@ -190,6 +244,7 @@ static const struct sdhci_pci_fixes sdhci_intel_mfd_sdio = { 
static const struct sdhci_pci_fixes sdhci_intel_mfd_emmc = {

	.quirks		= SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC,

	.probe_slot	= mfd_emmc_probe_slot,

	.remove_slot	= mfd_emmc_remove_slot,

};



/* O2Micro extra registers */
@@ -832,9 +887,25 @@ static int sdhci_pci_8bit_width(struct sdhci_host *host, int width) 
	return 0;

}



static void sdhci_pci_hw_reset(struct sdhci_host *host)

{

	struct sdhci_pci_slot *slot = sdhci_priv(host);

	int rst_n_gpio = slot->rst_n_gpio;



	if (!gpio_is_valid(rst_n_gpio))

		return;

	gpio_set_value_cansleep(rst_n_gpio, 0);

	/* For eMMC, minimum is 1us but give it 10us for good measure */

	udelay(10);

	gpio_set_value_cansleep(rst_n_gpio, 1);

	/* For eMMC, minimum is 200us but give it 300us for good measure */

	usleep_range(300, 1000);

}



static struct sdhci_ops sdhci_pci_ops = {

	.enable_dma	= sdhci_pci_enable_dma,

	.platform_8bit_width	= sdhci_pci_8bit_width,

	.hw_reset		= sdhci_pci_hw_reset,

};



/*****************************************************************************\
@@ -988,6 +1059,7 @@ static struct sdhci_pci_slot * __devinit sdhci_pci_probe_slot( 
	slot->chip = chip;

	slot->host = host;

	slot->pci_bar = bar;

	slot->rst_n_gpio = -EINVAL;



	host->hw_name = "PCI";

	host->ops = &sdhci_pci_ops;