rt-thread/bsp/raspberry-pi/raspi4-32/driver/drv_sdio.c

657 lines
19 KiB
C

/*
* Copyright (c) 2006-2020, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2020-10-27 bigmagic first version
*/
#include "mbox.h"
#include "raspi4.h"
#include "drv_sdio.h"
static rt_uint32_t mmc_base_clock = 0;
static rt_uint32_t sdCommandTable[] = {
SD_CMD_INDEX(0),
SD_CMD_RESERVED(1),
SD_CMD_INDEX(2) | SD_RESP_R2,
SD_CMD_INDEX(3) | SD_RESP_R1,
SD_CMD_INDEX(4),
SD_CMD_RESERVED(5), //SD_CMD_INDEX(5) | SD_RESP_R4,
SD_CMD_INDEX(6) | SD_RESP_R1,
SD_CMD_INDEX(7) | SD_RESP_R1b,
SD_CMD_INDEX(8) | SD_RESP_R1,
SD_CMD_INDEX(9) | SD_RESP_R2,
SD_CMD_INDEX(10) | SD_RESP_R2,
SD_CMD_INDEX(11) | SD_RESP_R1,
SD_CMD_INDEX(12) | SD_RESP_R1b | SD_CMD_TYPE_ABORT,
SD_CMD_INDEX(13) | SD_RESP_R1,
SD_CMD_RESERVED(14),
SD_CMD_INDEX(15),
SD_CMD_INDEX(16) | SD_RESP_R1,
SD_CMD_INDEX(17) | SD_RESP_R1 | SD_DATA_READ,
SD_CMD_INDEX(18) | SD_RESP_R1 | SD_DATA_READ | SD_CMD_MULTI_BLOCK | SD_CMD_BLKCNT_EN,
SD_CMD_INDEX(19) | SD_RESP_R1 | SD_DATA_READ,
SD_CMD_INDEX(20) | SD_RESP_R1b,
SD_CMD_RESERVED(21),
SD_CMD_RESERVED(22),
SD_CMD_INDEX(23) | SD_RESP_R1,
SD_CMD_INDEX(24) | SD_RESP_R1 | SD_DATA_WRITE,
SD_CMD_INDEX(25) | SD_RESP_R1 | SD_DATA_WRITE | SD_CMD_MULTI_BLOCK | SD_CMD_BLKCNT_EN,
SD_CMD_INDEX(26) | SD_RESP_R1 | SD_DATA_WRITE, //add
SD_CMD_INDEX(27) | SD_RESP_R1 | SD_DATA_WRITE,
SD_CMD_INDEX(28) | SD_RESP_R1b,
SD_CMD_INDEX(29) | SD_RESP_R1b,
SD_CMD_INDEX(30) | SD_RESP_R1 | SD_DATA_READ,
SD_CMD_RESERVED(31),
SD_CMD_INDEX(32) | SD_RESP_R1,
SD_CMD_INDEX(33) | SD_RESP_R1,
SD_CMD_RESERVED(34),
SD_CMD_INDEX(35) | SD_RESP_R1, //add
SD_CMD_INDEX(36) | SD_RESP_R1, //add
SD_CMD_RESERVED(37),
SD_CMD_INDEX(38) | SD_RESP_R1b,
SD_CMD_INDEX(39) | SD_RESP_R4, //add
SD_CMD_INDEX(40) | SD_RESP_R5, //add
SD_CMD_INDEX(41) | SD_RESP_R3, //add, mov from harbote
SD_CMD_RESERVED(42) | SD_RESP_R1,
SD_CMD_RESERVED(43),
SD_CMD_RESERVED(44),
SD_CMD_RESERVED(45),
SD_CMD_RESERVED(46),
SD_CMD_RESERVED(47),
SD_CMD_RESERVED(48),
SD_CMD_RESERVED(49),
SD_CMD_RESERVED(50),
SD_CMD_INDEX(51) | SD_RESP_R1 | SD_DATA_READ,
SD_CMD_RESERVED(52),
SD_CMD_RESERVED(53),
SD_CMD_RESERVED(54),
SD_CMD_INDEX(55) | SD_RESP_R3,
SD_CMD_INDEX(56) | SD_RESP_R1 | SD_CMD_ISDATA,
SD_CMD_RESERVED(57),
SD_CMD_RESERVED(58),
SD_CMD_RESERVED(59),
SD_CMD_RESERVED(60),
SD_CMD_RESERVED(61),
SD_CMD_RESERVED(62),
SD_CMD_RESERVED(63)
};
static inline rt_uint32_t read32(rt_uint32_t addr)
{
return (*((volatile unsigned int*)(addr)));
}
static inline void write32(rt_uint32_t addr, rt_uint32_t value)
{
(*((volatile unsigned int*)(addr))) = value;
}
rt_err_t sd_int(struct sdhci_pdata_t * pdat, rt_uint32_t mask)
{
rt_uint32_t r;
rt_uint32_t m = mask | INT_ERROR_MASK;
int cnt = 1000000;
while (!(read32(pdat->virt + EMMC_INTERRUPT) & (m | INT_ERROR_MASK)) && cnt--)
DELAY_MICROS(1);
r = read32(pdat->virt + EMMC_INTERRUPT);
if (cnt <= 0 || (r & INT_CMD_TIMEOUT) || (r & INT_DATA_TIMEOUT))
{
write32(pdat->virt + EMMC_INTERRUPT, r);
//qemu maybe can not use sdcard
//rt_kprintf("send cmd/data timeout wait for %x int: %x, status: %x\n",mask, r, read32(pdat->virt + EMMC_STATUS));
//return -RT_ETIMEOUT;
}
else if (r & INT_ERROR_MASK)
{
write32(pdat->virt + EMMC_INTERRUPT, r);
rt_kprintf("send cmd/data error %x -> %x\n",r, read32(pdat->virt + EMMC_INTERRUPT));
return -RT_ERROR;
}
write32(pdat->virt + EMMC_INTERRUPT, mask);
return RT_EOK;
}
rt_err_t sd_status(struct sdhci_pdata_t * pdat, unsigned int mask)
{
int cnt = 500000;
while ((read32(pdat->virt + EMMC_STATUS) & mask) && !(read32(pdat->virt + EMMC_INTERRUPT) & INT_ERROR_MASK) && cnt--)
DELAY_MICROS(1);
if (cnt <= 0)
{
return -RT_ETIMEOUT;
}
else if (read32(pdat->virt + EMMC_INTERRUPT) & INT_ERROR_MASK)
{
return -RT_ERROR;
}
return RT_EOK;
}
static rt_err_t raspi_transfer_command(struct sdhci_pdata_t * pdat, struct sdhci_cmd_t * cmd)
{
rt_uint32_t cmdidx;
rt_err_t ret = RT_EOK;
ret = sd_status(pdat, SR_CMD_INHIBIT);
if (ret)
{
rt_kprintf("ERROR: EMMC busy %d\n", ret);
return ret;
}
cmdidx = sdCommandTable[cmd->cmdidx];
if (cmdidx == 0xFFFFFFFF)
return -RT_EINVAL;
if (cmd->datarw == DATA_READ)
cmdidx |= SD_DATA_READ;
if (cmd->datarw == DATA_WRITE)
cmdidx |= SD_DATA_WRITE;
mmcsd_dbg("transfer cmd %x(%d) %x %x\n", cmdidx, cmd->cmdidx, cmd->cmdarg, read32(pdat->virt + EMMC_INTERRUPT));
write32(pdat->virt + EMMC_INTERRUPT,read32(pdat->virt + EMMC_INTERRUPT));
write32(pdat->virt + EMMC_ARG1, cmd->cmdarg);
write32(pdat->virt + EMMC_CMDTM, cmdidx);
if (cmd->cmdidx == SD_APP_OP_COND)
DELAY_MICROS(1000);
else if ((cmd->cmdidx == SD_SEND_IF_COND) || (cmd->cmdidx == APP_CMD))
DELAY_MICROS(100);
ret = sd_int(pdat, INT_CMD_DONE);
if (ret)
{
return ret;
}
if (cmd->resptype & RESP_MASK)
{
if (cmd->resptype & RESP_R2)
{
rt_uint32_t resp[4];
resp[0] = read32(pdat->virt + EMMC_RESP0);
resp[1] = read32(pdat->virt + EMMC_RESP1);
resp[2] = read32(pdat->virt + EMMC_RESP2);
resp[3] = read32(pdat->virt + EMMC_RESP3);
if (cmd->resptype == RESP_R2)
{
cmd->response[0] = resp[3]<<8 |((resp[2]>>24)&0xff);
cmd->response[1] = resp[2]<<8 |((resp[1]>>24)&0xff);
cmd->response[2] = resp[1]<<8 |((resp[0]>>24)&0xff);
cmd->response[3] = resp[0]<<8 ;
}
else
{
cmd->response[0] = resp[0];
cmd->response[1] = resp[1];
cmd->response[2] = resp[2];
cmd->response[3] = resp[3];
}
}
else
cmd->response[0] = read32(pdat->virt + EMMC_RESP0);
}
mmcsd_dbg("response: %x: %x %x %x %x (%x, %x)\n", cmd->resptype, cmd->response[0], cmd->response[1], cmd->response[2], cmd->response[3], read32(pdat->virt + EMMC_STATUS),read32(pdat->virt + EMMC_INTERRUPT));
return ret;
}
static rt_err_t read_bytes(struct sdhci_pdata_t * pdat, rt_uint32_t * buf, rt_uint32_t blkcount, rt_uint32_t blksize)
{
int c = 0;
rt_err_t ret;
int d;
while (c < blkcount)
{
if ((ret = sd_int(pdat, INT_READ_RDY)))
{
rt_kprintf("timeout happens when reading block %d\n",c);
return ret;
}
for (d=0; d < blksize / 4; d++)
if (read32(pdat->virt + EMMC_STATUS) & SR_READ_AVAILABLE)
buf[d] = read32(pdat->virt + EMMC_DATA);
c++;
buf += blksize / 4;
}
return RT_EOK;
}
static rt_err_t write_bytes(struct sdhci_pdata_t * pdat, rt_uint32_t * buf, rt_uint32_t blkcount, rt_uint32_t blksize)
{
int c = 0;
rt_err_t ret;
int d;
while (c < blkcount)
{
if ((ret = sd_int(pdat, INT_WRITE_RDY)))
{
return ret;
}
for (d=0; d < blksize / 4; d++)
write32(pdat->virt + EMMC_DATA, buf[d]);
c++;
buf += blksize / 4;
}
if ((ret = sd_int(pdat, INT_DATA_DONE)))
{
return ret;
}
return RT_EOK;
}
static rt_err_t raspi_transfer_data(struct sdhci_pdata_t * pdat, struct sdhci_cmd_t * cmd, struct sdhci_data_t * dat)
{
rt_uint32_t dlen = (rt_uint32_t)(dat->blkcnt * dat->blksz);
rt_err_t ret = sd_status(pdat, SR_DAT_INHIBIT);
if (ret)
{
rt_kprintf("ERROR: EMMC busy\n");
return ret;
}
if (dat->blkcnt > 1)
{
struct sdhci_cmd_t newcmd;
newcmd.cmdidx = SET_BLOCK_COUNT;
newcmd.cmdarg = dat->blkcnt;
newcmd.resptype = RESP_R1;
ret = raspi_transfer_command(pdat, &newcmd);
if (ret) return ret;
}
if(dlen < 512)
{
write32(pdat->virt + EMMC_BLKSIZECNT, dlen | 1 << 16);
}
else
{
write32(pdat->virt + EMMC_BLKSIZECNT, 512 | (dat->blkcnt) << 16);
}
if (dat->flag & DATA_DIR_READ)
{
cmd->datarw = DATA_READ;
ret = raspi_transfer_command(pdat, cmd);
if (ret) return ret;
mmcsd_dbg("read_block %d, %d\n", dat->blkcnt, dat->blksz );
ret = read_bytes(pdat, (rt_uint32_t *)dat->buf, dat->blkcnt, dat->blksz);
}
else if (dat->flag & DATA_DIR_WRITE)
{
cmd->datarw = DATA_WRITE;
ret = raspi_transfer_command(pdat, cmd);
if (ret) return ret;
mmcsd_dbg("write_block %d, %d", dat->blkcnt, dat->blksz );
ret = write_bytes(pdat, (rt_uint32_t *)dat->buf, dat->blkcnt, dat->blksz);
}
return ret;
}
static rt_err_t sdhci_transfer(struct sdhci_t * sdhci, struct sdhci_cmd_t * cmd, struct sdhci_data_t * dat)
{
struct sdhci_pdata_t * pdat = (struct sdhci_pdata_t *)sdhci->priv;
if (!dat)
return raspi_transfer_command(pdat, cmd);
return raspi_transfer_data(pdat, cmd, dat);
}
static void mmc_request_send(struct rt_mmcsd_host *host, struct rt_mmcsd_req *req)
{
struct sdhci_t *sdhci = (struct sdhci_t *)host->private_data;
struct sdhci_cmd_t cmd;
struct sdhci_cmd_t stop;
struct sdhci_data_t dat;
rt_memset(&cmd, 0, sizeof(struct sdhci_cmd_t));
rt_memset(&stop, 0, sizeof(struct sdhci_cmd_t));
rt_memset(&dat, 0, sizeof(struct sdhci_data_t));
cmd.cmdidx = req->cmd->cmd_code;
cmd.cmdarg = req->cmd->arg;
cmd.resptype =resp_type(req->cmd);
if (req->data)
{
dat.buf = (rt_uint8_t *)req->data->buf;
dat.flag = req->data->flags;
dat.blksz = req->data->blksize;
dat.blkcnt = req->data->blks;
req->cmd->err = sdhci_transfer(sdhci, &cmd, &dat);
}
else
{
req->cmd->err = sdhci_transfer(sdhci, &cmd, RT_NULL);
}
req->cmd->resp[3] = cmd.response[3];
req->cmd->resp[2] = cmd.response[2];
req->cmd->resp[1] = cmd.response[1];
req->cmd->resp[0] = cmd.response[0];
if (req->stop)
{
stop.cmdidx = req->stop->cmd_code;
stop.cmdarg = req->stop->arg;
cmd.resptype =resp_type(req->stop);
req->stop->err = sdhci_transfer(sdhci, &stop, RT_NULL);
}
mmcsd_req_complete(host);
}
rt_int32_t mmc_card_status(struct rt_mmcsd_host *host)
{
return 0;
}
static rt_err_t sdhci_detect(struct sdhci_t * sdhci)
{
return RT_EOK;
}
static rt_err_t sdhci_setwidth(struct sdhci_t * sdhci, rt_uint32_t width)
{
rt_uint32_t temp = 0;
struct sdhci_pdata_t * pdat = (struct sdhci_pdata_t *)sdhci->priv;
if (width == MMCSD_BUS_WIDTH_4)
{
temp = read32((pdat->virt + EMMC_CONTROL0));
temp |= C0_HCTL_HS_EN;
temp |= C0_HCTL_DWITDH; // always use 4 data lines:
write32((pdat->virt + EMMC_CONTROL0), temp);
}
return RT_EOK;
}
static uint32_t sd_get_clock_divider(rt_uint32_t sdHostVer ,rt_uint32_t base_clock, rt_uint32_t target_rate)
{
rt_uint32_t targetted_divisor = 0;
rt_uint32_t freq_select = 0;
rt_uint32_t upper_bits = 0;
rt_uint32_t ret = 0;
if(target_rate > base_clock)
targetted_divisor = 1;
else
{
targetted_divisor = base_clock / target_rate;
rt_uint32_t mod = base_clock % target_rate;
if(mod)
targetted_divisor--;
}
// Decide on the clock mode to use
// Currently only 10-bit divided clock mode is supported
// HCI version 3 or greater supports 10-bit divided clock mode
// This requires a power-of-two divider
// Find the first bit set
int divisor = -1;
for(int first_bit = 31; first_bit >= 0; first_bit--)
{
rt_uint32_t bit_test = (1 << first_bit);
if(targetted_divisor & bit_test)
{
divisor = first_bit;
targetted_divisor &= ~bit_test;
if(targetted_divisor)
{
// The divisor is not a power-of-two, increase it
divisor++;
}
break;
}
}
if(divisor == -1)
divisor = 31;
if(divisor >= 32)
divisor = 31;
if(divisor != 0)
divisor = (1 << (divisor - 1));
if(divisor >= 0x400)
divisor = 0x3ff;
freq_select = divisor & 0xff;
upper_bits = (divisor >> 8) & 0x3;
ret = (freq_select << 8) | (upper_bits << 6) | (0 << 5);
return ret;
}
static rt_err_t sdhci_setclock(struct sdhci_t * sdhci, rt_uint32_t clock)
{
rt_uint32_t temp = 0;
rt_uint32_t sdHostVer = 0;
int count = 100000;
struct sdhci_pdata_t * pdat = (struct sdhci_pdata_t *)(sdhci->priv);
while ((read32(pdat->virt + EMMC_STATUS) & (SR_CMD_INHIBIT | SR_DAT_INHIBIT)) && (--count))
DELAY_MICROS(1);
if (count <= 0)
{
rt_kprintf("EMMC: Set clock: timeout waiting for inhibit flags. Status %08x.\n",read32(pdat->virt + EMMC_STATUS));
return RT_ERROR;
}
// Switch clock off.
temp = read32((pdat->virt + EMMC_CONTROL1));
temp &= ~C1_CLK_EN;
write32((pdat->virt + EMMC_CONTROL1),temp);
DELAY_MICROS(10);
// Request the new clock setting and enable the clock
temp = read32(pdat->virt + EMMC_SLOTISR_VER);
sdHostVer = (temp & HOST_SPEC_NUM) >> HOST_SPEC_NUM_SHIFT;
int cdiv = sd_get_clock_divider(sdHostVer, mmc_base_clock, clock);
temp = read32((pdat->virt + EMMC_CONTROL1));
temp |= 1;
temp |= cdiv;
temp |= (7 << 16);
temp = (temp & 0xffff003f) | cdiv;
write32((pdat->virt + EMMC_CONTROL1),temp);
DELAY_MICROS(10);
// Enable the clock.
temp = read32(pdat->virt + EMMC_CONTROL1);
temp |= C1_CLK_EN;
write32((pdat->virt + EMMC_CONTROL1),temp);
DELAY_MICROS(10);
// Wait for clock to be stable.
count = 10000;
while (!(read32(pdat->virt + EMMC_CONTROL1) & C1_CLK_STABLE) && count--)
DELAY_MICROS(10);
if (count <= 0)
{
rt_kprintf("EMMC: ERROR: failed to get stable clock %d.\n", clock);
return RT_ERROR;
}
mmcsd_dbg("set stable clock %d.\n", clock);
return RT_EOK;
}
static void mmc_set_iocfg(struct rt_mmcsd_host *host, struct rt_mmcsd_io_cfg *io_cfg)
{
struct sdhci_t * sdhci = (struct sdhci_t *)host->private_data;
sdhci_setclock(sdhci, io_cfg->clock);
sdhci_setwidth(sdhci, io_cfg->bus_width);
}
static const struct rt_mmcsd_host_ops ops =
{
mmc_request_send,
mmc_set_iocfg,
RT_NULL,
RT_NULL,
};
static rt_err_t reset_emmc(struct sdhci_pdata_t * pdat)
{
rt_uint32_t control1;
//Reset the controller
control1 = read32((pdat->virt + EMMC_CONTROL1));
control1 |= (1 << 24);
// Disable clock
control1 &= ~(1 << 2);
control1 &= ~(1 << 0);
//temp |= C1_CLK_INTLEN | C1_TOUNIT_MAX;
write32((pdat->virt + EMMC_CONTROL1),control1);
int cnt = 10000;
do
{
DELAY_MICROS(10);
cnt = cnt - 1;
if(cnt == 0)
{
break;
}
} while ((read32(pdat->virt + EMMC_CONTROL1) & (0x7 << 24)) != 0);
// Enable SD Bus Power VDD1 at 3.3V
rt_uint32_t control0 = read32(pdat->virt + EMMC_CONTROL0);
control0 |= 0x0F << 8;
write32(pdat->virt + EMMC_CONTROL0, control0);
rt_thread_delay(100);
//usleep(2000);
// Check for a valid card
mmcsd_dbg("EMMC: checking for an inserted card\n");
cnt = 10000;
do
{
DELAY_MICROS(10);
cnt = cnt - 1;
if(cnt == 0)
{
break;
}
} while ((read32(pdat->virt + EMMC_STATUS) & (0x1 << 16)) == 0);
rt_uint32_t status_reg = read32(pdat->virt + EMMC_STATUS);
if((status_reg & (1 << 16)) == 0)
{
rt_kprintf("EMMC: no card inserted\n");
return -1;
}
else
{
mmcsd_dbg("EMMC: status: %08x\n", status_reg);
}
// Clear control2
write32(pdat->virt + EMMC_CONTROL2, 0);
// Get the base clock rate
mmc_base_clock = bcm271x_mbox_clock_get_rate(12);
if(mmc_base_clock == 0)
{
rt_kprintf("EMMC: assuming clock rate to be 100MHz\n");
mmc_base_clock = 100000000;
}
mmcsd_dbg("EMMC: setting clock rate is %d\n", mmc_base_clock);
return RT_EOK;
}
#ifdef RT_MMCSD_DBG
void dump_registers(struct sdhci_pdata_t * pdat)
{
rt_kprintf("EMMC registers:");
int i = EMMC_ARG2;
for (; i <= EMMC_CONTROL2; i += 4)
rt_kprintf("\t%x:%x\n", i, read32(pdat->virt + i));
rt_kprintf("\t%x:%x\n", 0x50, read32(pdat->virt + 0x50));
rt_kprintf("\t%x:%x\n", 0x70, read32(pdat->virt + 0x70));
rt_kprintf("\t%x:%x\n", 0x74, read32(pdat->virt + 0x74));
rt_kprintf("\t%x:%x\n", 0x80, read32(pdat->virt + 0x80));
rt_kprintf("\t%x:%x\n", 0x84, read32(pdat->virt + 0x84));
rt_kprintf("\t%x:%x\n", 0x88, read32(pdat->virt + 0x88));
rt_kprintf("\t%x:%x\n", 0x8c, read32(pdat->virt + 0x8c));
rt_kprintf("\t%x:%x\n", 0x90, read32(pdat->virt + 0x90));
rt_kprintf("\t%x:%x\n", 0xf0, read32(pdat->virt + 0xf0));
rt_kprintf("\t%x:%x\n", 0xfc, read32(pdat->virt + 0xfc));
}
#endif
int raspi_sdmmc_init(void)
{
rt_uint32_t virt;
struct rt_mmcsd_host * host = RT_NULL;
struct sdhci_pdata_t * pdat = RT_NULL;
struct sdhci_t * sdhci = RT_NULL;
#ifdef BSP_USING_SDIO0
host = mmcsd_alloc_host();
if (!host)
{
rt_kprintf("alloc host failed");
goto err;
}
sdhci = rt_malloc(sizeof(struct sdhci_t));
if (!sdhci)
{
rt_kprintf("alloc sdhci failed");
goto err;
}
rt_memset(sdhci, 0, sizeof(struct sdhci_t));
virt = MMC2_BASE_ADDR;
pdat = (struct sdhci_pdata_t *)rt_malloc(sizeof(struct sdhci_pdata_t));
RT_ASSERT(pdat != RT_NULL);
pdat->virt = (rt_uint32_t)virt;
reset_emmc(pdat);
sdhci->name = "sd0";
sdhci->voltages = VDD_33_34;
sdhci->width = MMCSD_BUSWIDTH_4;
sdhci->clock = 250 * 1000 * 1000;
sdhci->removeable = RT_TRUE;
sdhci->detect = sdhci_detect;
sdhci->setwidth = sdhci_setwidth;
sdhci->setclock = sdhci_setclock;
sdhci->transfer = sdhci_transfer;
sdhci->priv = pdat;
host->ops = &ops;
host->freq_min = 400000;
host->freq_max = 50000000;
host->valid_ocr = VDD_32_33 | VDD_33_34;
host->flags = MMCSD_MUTBLKWRITE | MMCSD_SUP_HIGHSPEED | MMCSD_SUP_SDIO_IRQ | MMCSD_BUSWIDTH_4;
host->max_seg_size = 2048;
host->max_dma_segs = 10;
host->max_blk_size = 512;
host->max_blk_count = 4096;
host->private_data = sdhci;
write32((pdat->virt + EMMC_IRPT_EN),0xffffffff);
write32((pdat->virt + EMMC_IRPT_MASK),0xffffffff);
#ifdef RT_MMCSD_DBG
dump_registers(pdat);
#endif
mmcsd_change(host);
#endif
return RT_EOK;
err:
if (host) rt_free(host);
if (sdhci) rt_free(sdhci);
return -RT_EIO;
}
INIT_DEVICE_EXPORT(raspi_sdmmc_init);