LXR uboot/doc/README.atmel

   1How to use SD/MMC cards with Atmel SoCs having MCI hardware
   2-----------------------------------------------------------
   32010-08-16 Reinhard Meyer <reinhard.meyer@emk-elektronik.de>
   4
   5This is a new approach to use Atmel MCI hardware with the
   6general MMC framework. Therefore it benefits from that
   7framework's abilities to handle SDHC Cards and the ability
   8to 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
  14It should work with all other ATMEL devices that have MCI,
  15including AVR32.
  16
  17The generic driver does NOT assign port pins to the MCI block
  18nor does it start the MCI clock. This has to be handled in a
  19board/SoC specific manner before the driver is initialized:
  20
  21example: this is added to at91sam9260_devices.c:
  22
  23#if defined(CONFIG_GENERIC_ATMEL_MCI)
  24void 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
  43the 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 */
  51int 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 */
  62int board_mmc_getcd(struct mmc *mmc)
  63{
  64        return !at91_get_gpio_value(CONFIG_SYS_MMC_CD_PIN);
  65}
  66
  67#endif
  68
  69and the board definition files needs:
  70
  71/* SD/MMC card */
  72#define CONFIG_MMC                      1
  73#define CONFIG_GENERIC_MMC              1
  74#define CONFIG_GENERIC_ATMEL_MCI        1
  75#define CONFIG_ATMEL_MCI_PORTB          1       /* Atmel XE-EK uses port B */
  76#define CONFIG_SYS_MMC_CD_PIN           AT91_PIN_PC9
  77#define CONFIG_CMD_MMC                  1
  78