1 How to use SD/MMC cards with Atmel SoCs having MCI hardware 2 ----------------------------------------------------------- 3 2010-08-16 Reinhard Meyer <reinhard.meyer (a] 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 16 The generic driver does NOT assign port pins to the MCI block 17 nor does it start the MCI clock. This has to be handled in a 18 board/SoC specific manner before the driver is initialized: 19 20 example: this is added to at91sam9260_devices.c: 21 22 #if defined(CONFIG_GENERIC_ATMEL_MCI) 23 void at91_mci_hw_init(void) 24 { 25 at91_set_a_periph(AT91_PIO_PORTA, 8, PUP); /* MCCK */ 26 #if defined(CONFIG_ATMEL_MCI_PORTB) 27 at91_set_b_periph(AT91_PIO_PORTA, 1, PUP); /* MCCDB */ 28 at91_set_b_periph(AT91_PIO_PORTA, 0, PUP); /* MCDB0 */ 29 at91_set_b_periph(AT91_PIO_PORTA, 5, PUP); /* MCDB1 */ 30 at91_set_b_periph(AT91_PIO_PORTA, 4, PUP); /* MCDB2 */ 31 at91_set_b_periph(AT91_PIO_PORTA, 3, PUP); /* MCDB3 */ 32 #else 33 at91_set_a_periph(AT91_PIO_PORTA, 7, PUP); /* MCCDA */ 34 at91_set_a_periph(AT91_PIO_PORTA, 6, PUP); /* MCDA0 */ 35 at91_set_a_periph(AT91_PIO_PORTA, 9, PUP); /* MCDA1 */ 36 at91_set_a_periph(AT91_PIO_PORTA, 10, PUP); /* MCDA2 */ 37 at91_set_a_periph(AT91_PIO_PORTA, 11, PUP); /* MCDA3 */ 38 #endif 39 } 40 #endif 41 42 the board specific file need added: 43 ... 44 #ifdef CONFIG_GENERIC_ATMEL_MCI 45 # include <mmc.h> 46 #endif 47 ... 48 #ifdef CONFIG_GENERIC_ATMEL_MCI 49 /* this is a weak define that we are overriding */ 50 int board_mmc_init(bd_t *bd) 51 { 52 /* Enable clock */ 53 at91_sys_write(AT91_PMC_PCER, 1 << AT91SAM9260_ID_MCI); 54 at91_mci_hw_init(); 55 56 /* This calls the atmel_mci_init in gen_atmel_mci.c */ 57 return atmel_mci_init((void *)AT91_BASE_MCI); 58 } 59 60 /* this is a weak define that we are overriding */ 61 int board_mmc_getcd(struct mmc *mmc) 62 { 63 return !at91_get_gpio_value(CONFIG_SYS_MMC_CD_PIN); 64 } 65 66 #endif 67 68 and the board definition files needs: 69 70 /* SD/MMC card */ 71 #define CONFIG_GENERIC_ATMEL_MCI 1 72 #define CONFIG_ATMEL_MCI_PORTB 1 /* Atmel XE-EK uses port B */ 73 #define CONFIG_SYS_MMC_CD_PIN AT91_PIN_PC9 74 #define CONFIG_CMD_MMC 1 75
