linux/drivers/mmc/core/sdio_io.c

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/*
* linux/drivers/mmc/core/sdio_io.c
*
* Copyright 2007 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*/
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/sdio.h>
#include <linux/mmc/sdio_func.h>
#include "sdio_ops.h"
/**
* sdio_claim_host - exclusively claim a bus for a certain SDIO function
* @func: SDIO function that will be accessed
*
* Claim a bus for a set of operations. The SDIO function given
* is used to figure out which bus is relevant.
*/
void sdio_claim_host(struct sdio_func *func)
{
BUG_ON(!func);
BUG_ON(!func->card);
mmc_claim_host(func->card->host);
}
EXPORT_SYMBOL_GPL(sdio_claim_host);
/**
* sdio_release_host - release a bus for a certain SDIO function
* @func: SDIO function that was accessed
*
* Release a bus, allowing others to claim the bus for their
* operations.
*/
void sdio_release_host(struct sdio_func *func)
{
BUG_ON(!func);
BUG_ON(!func->card);
mmc_release_host(func->card->host);
}
EXPORT_SYMBOL_GPL(sdio_release_host);
/**
* sdio_enable_func - enables a SDIO function for usage
* @func: SDIO function to enable
*
* Powers up and activates a SDIO function so that register
* access is possible.
*/
int sdio_enable_func(struct sdio_func *func)
{
int ret;
unsigned char reg;
unsigned long timeout;
BUG_ON(!func);
BUG_ON(!func->card);
pr_debug("SDIO: Enabling device %s...\n", sdio_func_id(func));
ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IOEx, 0, &reg);
if (ret)
goto err;
reg |= 1 << func->num;
ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IOEx, reg, NULL);
if (ret)
goto err;
/*
* FIXME: This should timeout based on information in the CIS,
* but we don't have card to parse that yet.
*/
timeout = jiffies + HZ;
while (1) {
ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IORx, 0, &reg);
if (ret)
goto err;
if (reg & (1 << func->num))
break;
ret = -ETIME;
if (time_after(jiffies, timeout))
goto err;
}
pr_debug("SDIO: Enabled device %s\n", sdio_func_id(func));
return 0;
err:
pr_debug("SDIO: Failed to enable device %s\n", sdio_func_id(func));
return ret;
}
EXPORT_SYMBOL_GPL(sdio_enable_func);
/**
* sdio_disable_func - disable a SDIO function
* @func: SDIO function to disable
*
* Powers down and deactivates a SDIO function. Register access
* to this function will fail until the function is reenabled.
*/
int sdio_disable_func(struct sdio_func *func)
{
int ret;
unsigned char reg;
BUG_ON(!func);
BUG_ON(!func->card);
pr_debug("SDIO: Disabling device %s...\n", sdio_func_id(func));
ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IOEx, 0, &reg);
if (ret)
goto err;
reg &= ~(1 << func->num);
ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IOEx, reg, NULL);
if (ret)
goto err;
pr_debug("SDIO: Disabled device %s\n", sdio_func_id(func));
return 0;
err:
pr_debug("SDIO: Failed to disable device %s\n", sdio_func_id(func));
return -EIO;
}
EXPORT_SYMBOL_GPL(sdio_disable_func);
/**
* sdio_readb - read a single byte from a SDIO function
* @func: SDIO function to access
* @addr: address to read
* @err_ret: optional status value from transfer
*
* Reads a single byte from the address space of a given SDIO
* function. If there is a problem reading the address, 0xff
* is returned and @err_ret will contain the error code.
*/
unsigned char sdio_readb(struct sdio_func *func, unsigned int addr,
int *err_ret)
{
int ret;
unsigned char val;
BUG_ON(!func);
if (err_ret)
*err_ret = 0;
ret = mmc_io_rw_direct(func->card, 0, func->num, addr, 0, &val);
if (ret) {
if (err_ret)
*err_ret = ret;
return 0xFF;
}
return val;
}
EXPORT_SYMBOL_GPL(sdio_readb);
/**
* sdio_writeb - write a single byte to a SDIO function
* @func: SDIO function to access
* @b: byte to write
* @addr: address to write to
* @err_ret: optional status value from transfer
*
* Writes a single byte to the address space of a given SDIO
* function. @err_ret will contain the status of the actual
* transfer.
*/
void sdio_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,
int *err_ret)
{
int ret;
BUG_ON(!func);
ret = mmc_io_rw_direct(func->card, 1, func->num, addr, b, NULL);
if (err_ret)
*err_ret = ret;
}
EXPORT_SYMBOL_GPL(sdio_writeb);