| Reinhard Meyer | c718a56 | 2010-08-13 10:31:06 +0200 | [diff] [blame] | 1 | How to use SD/MMC cards with Atmel SoCs having MCI hardware |
| 2 | ----------------------------------------------------------- |
| 3 | 2010-08-16 Reinhard Meyer <reinhard.meyer@emk-elektronik.de> |
| 4 | |
| 5 | This is a new approach to use Atmel MCI hardware with the |
| 6 | general MMC framework. Therefore it benefits from that |
| 7 | framework's abilities to handle SDHC Cards and the ability |
| 8 | to write blocks. |
| 9 | |
| 10 | - AT91SAM9XE512 (tested, will definitely work with XE128 and XE256) |
| 11 | - AT91SAM9260 (not tested, but MCI is to AT91SAM9XE) |
| 12 | - AT91SAM9G20 (not tested, should work) |
| 13 | |
| 14 | It should work with all other ATMEL devices that have MCI, |
| 15 | including AVR32. |
| 16 | |
| 17 | The generic driver does NOT assign port pins to the MCI block |
| 18 | nor does it start the MCI clock. This has to be handled in a |
| 19 | board/SoC specific manner before the driver is initialized: |
| 20 | |
| 21 | example: this is added to at91sam9260_devices.c: |
| 22 | |
| 23 | #if defined(CONFIG_ATMEL_MCI) || defined(CONFIG_GENERIC_ATMEL_MCI) |
| 24 | void at91_mci_hw_init(void) |
| 25 | { |
| 26 | at91_set_a_periph(AT91_PIO_PORTA, 8, PUP); /* MCCK */ |
| 27 | #if defined(CONFIG_ATMEL_MCI_PORTB) |
| 28 | at91_set_b_periph(AT91_PIO_PORTA, 1, PUP); /* MCCDB */ |
| 29 | at91_set_b_periph(AT91_PIO_PORTA, 0, PUP); /* MCDB0 */ |
| 30 | at91_set_b_periph(AT91_PIO_PORTA, 5, PUP); /* MCDB1 */ |
| 31 | at91_set_b_periph(AT91_PIO_PORTA, 4, PUP); /* MCDB2 */ |
| 32 | at91_set_b_periph(AT91_PIO_PORTA, 3, PUP); /* MCDB3 */ |
| 33 | #else |
| 34 | at91_set_a_periph(AT91_PIO_PORTA, 7, PUP); /* MCCDA */ |
| 35 | at91_set_a_periph(AT91_PIO_PORTA, 6, PUP); /* MCDA0 */ |
| 36 | at91_set_a_periph(AT91_PIO_PORTA, 9, PUP); /* MCDA1 */ |
| 37 | at91_set_a_periph(AT91_PIO_PORTA, 10, PUP); /* MCDA2 */ |
| 38 | at91_set_a_periph(AT91_PIO_PORTA, 11, PUP); /* MCDA3 */ |
| 39 | #endif |
| 40 | } |
| 41 | #endif |
| 42 | |
| 43 | the board specific file need added: |
| 44 | ... |
| 45 | #ifdef CONFIG_GENERIC_ATMEL_MCI |
| 46 | # include <mmc.h> |
| 47 | #endif |
| 48 | ... |
| 49 | #ifdef CONFIG_GENERIC_ATMEL_MCI |
| 50 | /* this is a weak define that we are overriding */ |
| 51 | int board_mmc_init(bd_t *bd) |
| 52 | { |
| 53 | /* Enable clock */ |
| 54 | at91_sys_write(AT91_PMC_PCER, 1 << AT91SAM9260_ID_MCI); |
| 55 | at91_mci_hw_init(); |
| 56 | |
| 57 | /* This calls the atmel_mci_init in gen_atmel_mci.c */ |
| 58 | return atmel_mci_init((void *)AT91_BASE_MCI); |
| 59 | } |
| 60 | |
| 61 | /* this is a weak define that we are overriding */ |
| 62 | int board_mmc_getcd(u8 *cd, struct mmc *mmc) |
| 63 | { |
| 64 | /* |
| 65 | * the only currently existing use of this function |
| 66 | * (fsl_esdhc.c) suggests this function must return |
| 67 | * *cs = TRUE if a card is NOT detected -> in most |
| 68 | * cases the value of the pin when the detect switch |
| 69 | * closes to GND |
| 70 | */ |
| 71 | *cd = at91_get_gpio_value (CONFIG_SYS_MMC_CD_PIN) ? 1 : 0; |
| 72 | return 0; |
| 73 | } |
| 74 | |
| 75 | #endif |
| 76 | |
| 77 | and the board definition files needs: |
| 78 | |
| 79 | /* SD/MMC card */ |
| 80 | #define CONFIG_MMC 1 |
| 81 | #define CONFIG_GENERIC_MMC 1 |
| 82 | #define CONFIG_GENERIC_ATMEL_MCI 1 |
| 83 | #define CONFIG_ATMEL_MCI_PORTB 1 /* Atmel XE-EK uses port B */ |
| 84 | #define CONFIG_SYS_MMC_CD_PIN AT91_PIN_PC9 |
| 85 | #define CONFIG_CMD_MMC 1 |