[patch 4/5] MMC OMAP driver

[patch 4/5] MMC OMAP driver

[Anderson Briglia]

Some MMC cards don't set the R1_READY_FOR_DATA bit if EOFB
interrupt comes first. In this case we need to mask R1_READY_FOR_DATA
to avoid polling card status forever.
This patch needs to be discussed as it requires interface change.
This interface change is done here only for omap for now.

Signed-off-by: Tony Lindgren <tony@atomide.com>

Index: linux-2.6.15-mmc_omap/drivers/mmc/mmc_block.c
===================================================================
--- linux-2.6.15-mmc_omap.orig/drivers/mmc/mmc_block.c	2006-01-26 16:57:08.000000000 -0400
+++ linux-2.6.15-mmc_omap/drivers/mmc/mmc_block.c	2006-01-26 17:04:52.000000000 -0400
@@ -218,6 +218,10 @@ static int mmc_blk_issue_rq(struct mmc_q
 			goto cmd_err;
 		}

+		/* No need to check card status after a read */
+		if (rq_data_dir(req) == READ)
+			goto card_ready;
+
 		do {
 			int err;

@@ -239,6 +243,8 @@ static int mmc_blk_issue_rq(struct mmc_q
 		if (mmc_decode_status(cmd.resp))
 			goto cmd_err;
 #endif
+
+card_ready:
 		/*
 		 * A block was successfully transferred.
 		 */
@@ -336,6 +342,7 @@ static struct mmc_blk_data *mmc_blk_allo

 	card_ready:

+card_ready:
 		/*
 		 * As discussed on lkml, GENHD_FL_REMOVABLE should:
 		 *
Index: linux-2.6.15-mmc_omap/drivers/mmc/omap.c
===================================================================
--- linux-2.6.15-mmc_omap.orig/drivers/mmc/omap.c	2006-01-26 16:57:11.000000000 -0400
+++ linux-2.6.15-mmc_omap/drivers/mmc/omap.c	2006-01-26 16:57:11.000000000 -0400
@@ -319,7 +319,7 @@ mmc_omap_dma_done(struct mmc_omap_host *
 }

 static void
-mmc_omap_cmd_done(struct mmc_omap_host *host, struct mmc_command *cmd)
+mmc_omap_cmd_done(struct mmc_omap_host *host, struct mmc_command *cmd, int card_ready)
 {
 	host->cmd = NULL;

@@ -332,6 +332,9 @@ mmc_omap_cmd_done(struct mmc_omap_host *
 		cmd->resp[0] =
 			OMAP_MMC_READ(host->base, RSP6) |
 			(OMAP_MMC_READ(host->base, RSP7) << 16);
+		if (card_ready) {
+			cmd->resp[0] |= R1_READY_FOR_DATA;
+		}
 		break;
 	case MMC_RSP_LONG:
 		/* response type 2 */
@@ -428,6 +431,7 @@ static irqreturn_t mmc_omap_irq(int irq,
 	u16 status;
 	int end_command;
 	int end_transfer;
+	int card_ready;
 	int transfer_error;

 	if (host->cmd == NULL && host->data == NULL) {
@@ -442,6 +446,7 @@ static irqreturn_t mmc_omap_irq(int irq,

 	end_command = 0;
 	end_transfer = 0;
+	card_ready = 0;
 	transfer_error = 0;

 	while ((status = OMAP_MMC_READ(host->base, STAT)) != 0) {
@@ -542,10 +547,19 @@ static irqreturn_t mmc_omap_irq(int irq,
 		    (!(status & OMAP_MMC_STAT_A_EMPTY))) {
 			end_command = 1;
 		}
+		/* Some cards produce EOFB interrupt and never
+		 * raise R1_READY_FOR_DATA bit after that.
+		 * To avoid infinite card status polling loop,
+		 * we must fake that bit to MMC layer.
+		 */
+		if ((status & OMAP_MMC_STAT_END_OF_CMD) &&
+				(status & OMAP_MMC_STAT_END_BUSY)) {
+			card_ready = 1;
+		}
 	}

 	if (end_command) {
-		mmc_omap_cmd_done(host, host->cmd);
+		mmc_omap_cmd_done(host, host->cmd, card_ready);
 	}
 	if (transfer_error)
 		mmc_omap_xfer_done(host, host->data);

Re: [patch 4/5] MMC OMAP driver

[Pierre Ossman]

Anderson Briglia wrote:
> Some MMC cards don't set the R1_READY_FOR_DATA bit if EOFB
> interrupt comes first. In this case we need to mask R1_READY_FOR_DATA
> to avoid polling card status forever.
> This patch needs to be discussed as it requires interface change.
> This interface change is done here only for omap for now.
> 
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> 

> @@ -336,6 +342,7 @@ static struct mmc_blk_data *mmc_blk_allo
> 
>  	card_ready:
> 
> +card_ready:
>  		/*
>  		 * As discussed on lkml, GENHD_FL_REMOVABLE should:
>  		 *

This chunk seems incorrect.

> @@ -542,10 +547,19 @@ static irqreturn_t mmc_omap_irq(int irq,
>  		    (!(status & OMAP_MMC_STAT_A_EMPTY))) {
>  			end_command = 1;
>  		}
> +		/* Some cards produce EOFB interrupt and never
> +		 * raise R1_READY_FOR_DATA bit after that.
> +		 * To avoid infinite card status polling loop,
> +		 * we must fake that bit to MMC layer.
> +		 */
> +		if ((status & OMAP_MMC_STAT_END_OF_CMD) &&
> +				(status & OMAP_MMC_STAT_END_BUSY)) {
> +			card_ready = 1;
> +		}
>  	}
> 
>  	if (end_command) {
> -		mmc_omap_cmd_done(host, host->cmd);
> +		mmc_omap_cmd_done(host, host->cmd, card_ready);
>  	}
>  	if (transfer_error)
>  		mmc_omap_xfer_done(host, host->data);

This sounds highly suspicious. Have you tried the card on another
controller? I do not like this mix of fixing it both in the driver and
in the MMC layer. Either it's a hardware issue and should be fixed in
the driver, or it's a generic problem and should be fixed in the MMC layer.

Rgds
Pierre