Commit e1bfad6d authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
Browse files

mmc: sdhci-pci: Add support for drive strength selection for SPT 



Implement the select_drive_strength callback to provide
drive strength selection for Intel SPT.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent cb849648

drivers/mmc/host/sdhci-pci-data.c

+3 −0
Original line number Diff line number Diff line
@@ -3,3 +3,6 @@ 


struct sdhci_pci_data *(*sdhci_pci_get_data)(struct pci_dev *pdev, int slotno);

EXPORT_SYMBOL_GPL(sdhci_pci_get_data);



int sdhci_pci_spt_drive_strength;

EXPORT_SYMBOL_GPL(sdhci_pci_spt_drive_strength);

drivers/mmc/host/sdhci-pci.c

+83 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/slab.h>

#include <linux/device.h>

#include <linux/mmc/host.h>

#include <linux/mmc/mmc.h>

#include <linux/scatterlist.h>

#include <linux/io.h>

#include <linux/gpio.h>
@@ -266,6 +267,69 @@ static void sdhci_pci_int_hw_reset(struct sdhci_host *host) 
	usleep_range(300, 1000);

}



static int spt_select_drive_strength(struct sdhci_host *host,

				     struct mmc_card *card,

				     unsigned int max_dtr,

				     int host_drv, int card_drv, int *drv_type)

{

	int drive_strength;



	if (sdhci_pci_spt_drive_strength > 0)

		drive_strength = sdhci_pci_spt_drive_strength & 0xf;

	else

		drive_strength = 1; /* 33-ohm */



	if ((mmc_driver_type_mask(drive_strength) & card_drv) == 0)

		drive_strength = 0; /* Default 50-ohm */



	return drive_strength;

}



/* Try to read the drive strength from the card */

static void spt_read_drive_strength(struct sdhci_host *host)

{

	u32 val, i, t;

	u16 m;



	if (sdhci_pci_spt_drive_strength)

		return;



	sdhci_pci_spt_drive_strength = -1;



	m = sdhci_readw(host, SDHCI_HOST_CONTROL2) & 0x7;

	if (m != 3 && m != 5)

		return;

	val = sdhci_readl(host, SDHCI_PRESENT_STATE);

	if (val & 0x3)

		return;

	sdhci_writel(host, 0x007f0023, SDHCI_INT_ENABLE);

	sdhci_writel(host, 0, SDHCI_SIGNAL_ENABLE);

	sdhci_writew(host, 0x10, SDHCI_TRANSFER_MODE);

	sdhci_writeb(host, 0xe, SDHCI_TIMEOUT_CONTROL);

	sdhci_writew(host, 512, SDHCI_BLOCK_SIZE);

	sdhci_writew(host, 1, SDHCI_BLOCK_COUNT);

	sdhci_writel(host, 0, SDHCI_ARGUMENT);

	sdhci_writew(host, 0x83b, SDHCI_COMMAND);

	for (i = 0; i < 1000; i++) {

		val = sdhci_readl(host, SDHCI_INT_STATUS);

		if (val & 0xffff8000)

			return;

		if (val & 0x20)

			break;

		udelay(1);

	}

	val = sdhci_readl(host, SDHCI_PRESENT_STATE);

	if (!(val & 0x800))

		return;

	for (i = 0; i < 47; i++)

		val = sdhci_readl(host, SDHCI_BUFFER);

	t = val & 0xf00;

	if (t != 0x200 && t != 0x300)

		return;



	sdhci_pci_spt_drive_strength = 0x10 | ((val >> 12) & 0xf);

}



static int byt_emmc_probe_slot(struct sdhci_pci_slot *slot)

{

	slot->host->mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE |
@@ -276,6 +340,10 @@ static int byt_emmc_probe_slot(struct sdhci_pci_slot *slot) 
	slot->hw_reset = sdhci_pci_int_hw_reset;

	if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BSW_EMMC)

		slot->host->timeout_clk = 1000; /* 1000 kHz i.e. 1 MHz */

	if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_SPT_EMMC) {

		spt_read_drive_strength(slot->host);

		slot->select_drive_strength = spt_select_drive_strength;

	}

	return 0;

}
@@ -1203,6 +1271,20 @@ static void sdhci_pci_hw_reset(struct sdhci_host *host) 
		slot->hw_reset(host);

}



static int sdhci_pci_select_drive_strength(struct sdhci_host *host,

					   struct mmc_card *card,

					   unsigned int max_dtr, int host_drv,

					   int card_drv, int *drv_type)

{

	struct sdhci_pci_slot *slot = sdhci_priv(host);



	if (!slot->select_drive_strength)

		return 0;



	return slot->select_drive_strength(host, card, max_dtr, host_drv,

					   card_drv, drv_type);

}



static const struct sdhci_ops sdhci_pci_ops = {

	.set_clock	= sdhci_set_clock,

	.enable_dma	= sdhci_pci_enable_dma,
@@ -1210,6 +1292,7 @@ static const struct sdhci_ops sdhci_pci_ops = { 
	.reset		= sdhci_reset,

	.set_uhs_signaling = sdhci_set_uhs_signaling,

	.hw_reset		= sdhci_pci_hw_reset,

	.select_drive_strength	= sdhci_pci_select_drive_strength,

};



/*****************************************************************************\

drivers/mmc/host/sdhci-pci.h

+4 −0
Original line number Diff line number Diff line
@@ -72,6 +72,10 @@ struct sdhci_pci_slot { 
	bool			cd_override_level;



	void (*hw_reset)(struct sdhci_host *host);

	int (*select_drive_strength)(struct sdhci_host *host,

				     struct mmc_card *card,

				     unsigned int max_dtr, int host_drv,

				     int card_drv, int *drv_type);

};



struct sdhci_pci_chip {

include/linux/mmc/sdhci-pci-data.h

+2 −0
Original line number Diff line number Diff line
@@ -15,4 +15,6 @@ struct sdhci_pci_data { 
extern struct sdhci_pci_data *(*sdhci_pci_get_data)(struct pci_dev *pdev,

				int slotno);



extern int sdhci_pci_spt_drive_strength;



#endif