| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677 |
- How to use SD/MMC cards with Atmel SoCs having MCI hardware
- -----------------------------------------------------------
- 2010-08-16 Reinhard Meyer <reinhard.meyer@emk-elektronik.de>
- This is a new approach to use Atmel MCI hardware with the
- general MMC framework. Therefore it benefits from that
- framework's abilities to handle SDHC Cards and the ability
- to write blocks.
- - AT91SAM9XE512 (tested, will definitely work with XE128 and XE256)
- - AT91SAM9260 (not tested, but MCI is to AT91SAM9XE)
- - AT91SAM9G20 (not tested, should work)
- It should work with all other ATMEL devices that have MCI,
- including AVR32.
- The generic driver does NOT assign port pins to the MCI block
- nor does it start the MCI clock. This has to be handled in a
- board/SoC specific manner before the driver is initialized:
- example: this is added to at91sam9260_devices.c:
- #if defined(CONFIG_GENERIC_ATMEL_MCI)
- void at91_mci_hw_init(void)
- {
- at91_set_a_periph(AT91_PIO_PORTA, 8, PUP); /* MCCK */
- #if defined(CONFIG_ATMEL_MCI_PORTB)
- at91_set_b_periph(AT91_PIO_PORTA, 1, PUP); /* MCCDB */
- at91_set_b_periph(AT91_PIO_PORTA, 0, PUP); /* MCDB0 */
- at91_set_b_periph(AT91_PIO_PORTA, 5, PUP); /* MCDB1 */
- at91_set_b_periph(AT91_PIO_PORTA, 4, PUP); /* MCDB2 */
- at91_set_b_periph(AT91_PIO_PORTA, 3, PUP); /* MCDB3 */
- #else
- at91_set_a_periph(AT91_PIO_PORTA, 7, PUP); /* MCCDA */
- at91_set_a_periph(AT91_PIO_PORTA, 6, PUP); /* MCDA0 */
- at91_set_a_periph(AT91_PIO_PORTA, 9, PUP); /* MCDA1 */
- at91_set_a_periph(AT91_PIO_PORTA, 10, PUP); /* MCDA2 */
- at91_set_a_periph(AT91_PIO_PORTA, 11, PUP); /* MCDA3 */
- #endif
- }
- #endif
- the board specific file need added:
- ...
- #ifdef CONFIG_GENERIC_ATMEL_MCI
- # include <mmc.h>
- #endif
- ...
- #ifdef CONFIG_GENERIC_ATMEL_MCI
- /* this is a weak define that we are overriding */
- int board_mmc_init(bd_t *bd)
- {
- /* Enable clock */
- at91_sys_write(AT91_PMC_PCER, 1 << AT91SAM9260_ID_MCI);
- at91_mci_hw_init();
- /* This calls the atmel_mci_init in gen_atmel_mci.c */
- return atmel_mci_init((void *)AT91_BASE_MCI);
- }
- /* this is a weak define that we are overriding */
- int board_mmc_getcd(struct mmc *mmc)
- {
- return !at91_get_gpio_value(CONFIG_SYS_MMC_CD_PIN);
- }
- #endif
- and the board definition files needs:
- /* SD/MMC card */
- #define CONFIG_MMC 1
- #define CONFIG_GENERIC_MMC 1
- #define CONFIG_GENERIC_ATMEL_MCI 1
- #define CONFIG_ATMEL_MCI_PORTB 1 /* Atmel XE-EK uses port B */
- #define CONFIG_SYS_MMC_CD_PIN AT91_PIN_PC9
- #define CONFIG_CMD_MMC 1
|
