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Merge branch 'pu/mmc-spi' into next

This commit is contained in:
Sascha Hauer 2011-11-28 11:42:08 +01:00
parent ad9ef4c148 3db0a1e7fe
commit 97e0b488a9
2 changed files with 13 additions and 17 deletions
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1
drivers/mci/Kconfig
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@ -81,6 +81,7 @@ config MCI_ATMEL
config MCI_SPI
bool "MMC/SD over SPI"
depends on SPI
help
Some systems access MMC/SD/SDIO cards using a SPI controller
instead of using a "native" MMC/SD/SDIO controller. This has a

29
drivers/mci/mci_spi.c
View File

@ -64,23 +64,6 @@
#define RTOUT 3000000 /* 1 sec */
#define WTOUT 3000000 /* 1 sec */
#ifndef CONFIG_MMC_SPI_CRC_ON
/* Note that while the CRC, in general, is ignored in SPI mode, the very first
* command must be followed by a valid CRC, since the card is not yet in SPI mode.
* The CRC byte for a CMD0 command with a zero argument is a constant 0x4A. For
* simplicity, this CRC byte is always sent with every command.
*/
static inline u8 crc7(u8 crc, const u8 *buffer, size_t len)
{
/* This is the crc7 value for a CMD0 command with a zero argument.
* It'll be left shifted and ored with '1' in mmc_spi_command_send
* to give 0x95 (also known as the CMD0 constant CRC value...)
*/
return 0x4A;
}
#endif
struct mmc_spi_host {
struct mci_host mci;
struct spi_device *spi;
@ -141,6 +124,14 @@ mmc_spi_writebytes(struct mmc_spi_host *host, unsigned len, void *data)
return status;
}
/*
* Note that while the CRC, in general, is ignored in SPI mode, the very first
* command must be followed by a valid CRC, since the card is not yet in SPI mode.
* The CRC byte for a CMD0 command with a zero argument is a constant 0x4A. For
* simplicity, this CRC byte is always sent with every command.
*/
#define MMC_SPI_CMD0_CRC ((0x4a << 1) | 0x1)
static int mmc_spi_command_send(struct mmc_spi_host *host, struct mci_cmd *cmd)
{
uint8_t r1;
@ -153,7 +144,11 @@ static int mmc_spi_command_send(struct mmc_spi_host *host, struct mci_cmd *cmd)
command[3] = cmd->cmdarg >> 16;
command[4] = cmd->cmdarg >> 8;
command[5] = cmd->cmdarg;
#ifdef CONFIG_MMC_SPI_CRC_ON
command[6] = (crc7(0, &command[1], 5) << 1) | 0x01;
#else
command[6] = MMC_SPI_CMD0_CRC;
#endif
mmc_spi_writebytes(host, 7, command);