[U-Boot] [PATCH v3 2/6] MVEBUMMC : Speed up access time

[Pantelis Antoniou]

Hi Gérald,

> On Dec 13, 2014, at 22:35 , Gérald Kerma <drEagle at doukki.net> wrote:
> 
> Get about 40x faster access on SHEEVAPLUG MMC
> Fix some SD type compatibility
> 
> Changes in v3:
> - fix the HW_STATE (from linux mvsdio)
> - review delays and timeouts
> 
> Changes in v2:
> - increase number of loops
> - remove initial delay
> 
> Changes in v1:
> - review all loops, delays and timeouts
> 
> Signed-off-by: Gérald Kerma <drEagle at doukki.net>
> ---
> drivers/mmc/mvebu_mmc.c | 48 +++++++++++++++++++++++++++++++-----------------
> include/mvebu_mmc.h     |  1 +
> 2 files changed, 32 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/mmc/mvebu_mmc.c b/drivers/mmc/mvebu_mmc.c
> index 063d4da..91a9be0 100644
> --- a/drivers/mmc/mvebu_mmc.c
> +++ b/drivers/mmc/mvebu_mmc.c
> @@ -23,6 +23,8 @@ DECLARE_GLOBAL_DATA_PTR;
> 
> #define MVEBU_TARGET_DRAM 0
> 
> +#define TIMEOUT_DELAY	5*CONFIG_SYS_HZ		/* wait 5 seconds */
> +
> static void mvebu_mmc_write(u32 offs, u32 val)
> {
> 	writel(val, CONFIG_SYS_MMC_BASE + (offs));
> @@ -63,7 +65,7 @@ static int mvebu_mmc_setup_data(struct mmc_data *data)
> static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
> 			      struct mmc_data *data)
> {
> -	int timeout = 10;
> +	ulong start;
> 	ushort waittype = 0;
> 	ushort resptype = 0;
> 	ushort xfertype = 0;
> @@ -72,19 +74,33 @@ static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
> 	debug("cmdidx [0x%x] resp_type[0x%x] cmdarg[0x%x]\n",
> 	      cmd->cmdidx, cmd->resp_type, cmd->cmdarg);
> 
> -	udelay(10*1000);
> -
> 	debug("%s: cmd %d (hw state 0x%04x)\n", DRIVER_NAME,
> 	      cmd->cmdidx, mvebu_mmc_read(SDIO_HW_STATE));
> 
> -	/* Checking if card is busy */
> -	while ((mvebu_mmc_read(SDIO_HW_STATE) & CARD_BUSY)) {
> -		if (timeout == 0) {
> -			printf("%s: card busy!\n", DRIVER_NAME);
> -			return -1;
> -		}
> -		timeout--;
> -		udelay(1000);
> +	/*
> +	 * Hardware weirdness.  The FIFO_EMPTY bit of the HW_STATE
> +	 * register is sometimes not set before a while when some
> +	 * "unusual" data block sizes are used (such as with the SWITCH
> +	 * command), even despite the fact that the XFER_DONE interrupt
> +	 * was raised.  And if another data transfer starts before
> +	 * this bit comes to good sense (which eventually happens by
> +	 * itself) then the new transfer simply fails with a timeout.
> +	 */
> +	if (!(mvebu_mmc_read(SDIO_HW_STATE) & CMD_FIFO_EMPTY)) {
> +		ushort hw_state, count = 0;
> +
> +		start = get_timer(0);
> +		do {
> +			hw_state = mvebu_mmc_read(SDIO_HW_STATE);
> +			if ((get_timer(0) - start) > TIMEOUT_DELAY) {
> +				printf("%s : FIFO_EMPTY bit missing\n",
> +				       DRIVER_NAME);
> +				break;
> +			}
> +			count++;
> +		} while (!(hw_state & CMD_FIFO_EMPTY));
> +		debug("%s *** wait for FIFO_EMPTY bit (hw=0x%04x, count=%d, jiffies=%ld)\n",
> +		      DRIVER_NAME, hw_state, count, (get_timer(0) - (start)));
> 	}
> 
> 	/* Set up for a data transfer if we have one */
> @@ -147,8 +163,7 @@ static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
> 	mvebu_mmc_write(SDIO_NOR_INTR_EN, SDIO_POLL_MASK);
> 	mvebu_mmc_write(SDIO_ERR_INTR_EN, SDIO_POLL_MASK);
> 
> -	/* Waiting for completion */
> -	timeout = 1000000;
> +	start = get_timer(0);
> 
> 	while (!((mvebu_mmc_read(SDIO_NOR_INTR_STATUS)) & waittype)) {
> 		if (mvebu_mmc_read(SDIO_NOR_INTR_STATUS) & SDIO_NOR_ERROR) {
> @@ -161,13 +176,12 @@ static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
> 			return COMM_ERR;
> 		}
> 
> -		timeout--;
> -		udelay(1);
> -		if (timeout <= 0) {
> -			printf("%s: command timed out\n", DRIVER_NAME);
> +		if ((get_timer(0) - start) > TIMEOUT_DELAY) {
> +			debug("%s: command timed out\n", DRIVER_NAME);
> 			return TIMEOUT;
> 		}
> 	}
> +
> 	if (mvebu_mmc_read(SDIO_ERR_INTR_STATUS) &
> 		(SDIO_ERR_CMD_TIMEOUT | SDIO_ERR_DATA_TIMEOUT))
> 		return TIMEOUT;
> diff --git a/include/mvebu_mmc.h b/include/mvebu_mmc.h
> index 28d98fe..7fb71f7 100644
> --- a/include/mvebu_mmc.h
> +++ b/include/mvebu_mmc.h
> @@ -79,6 +79,7 @@
> #define CMD_INHIBIT				(1 << 0)
> #define CMD_TXACTIVE				(1 << 8)
> #define CMD_RXACTIVE				(1 << 9)
> +#define CMD_FIFO_EMPTY				(1 << 13)
> #define CMD_AUTOCMD12ACTIVE			(1 << 14)
> #define CMD_BUS_BUSY				(CMD_AUTOCMD12ACTIVE |	\
> 						CMD_RXACTIVE |	\
> -- 
> 2.1.3

Applied, thanks

— Pantelis