mmc: msm_sdcc: Reduce command timeouts and improve reliability.

Based on an original patch by Brent DeGraaf:

"Previous versions of the SD driver were beset with excessive command
timeouts. These timeouts were silent by default, but happened
frequently, especially during heavy system activity and concurrent
access of two or more SD devices. Worst case, these timeouts would
occasionally hit at the end of a successful write, resulting in false
failures that could adversely affect journaling file systems if timing
was unfortunate. This update tightens the association and timing between
dma transfers and the commands that trigger them by utilizing a new api
implemented in the datamover.  In addition, it also fixes a dma cache
coherency issue that was exposed during testing of this fix that
occasionally resulted in card corruption.  Processing of results in the
interrupt status routine was modified to process command results prior to
data because overwritten command results were observed during testing
since the data section can result in command issuances of its own.
This change also eliminates the software command timeout, relying entirely
on the hardware version, since the software timeout was found to cause
problems of its own after extensive testing (having hardware timer and
software timers addressing the same issue was found to cause a race
condition under heavy system load)."

This change originally added PROG_DONE handling, which has been split out
into a separate patch. Also on our platform, the data mover driver maintains
coherency to ensure API reliability, so the above mentioned cache corruption
issue was not an issue for us.

Signed-off-by: San Mehat <san@google.com>
Cc: Brian Swetland <swetland@google.com>

Change-Id: Ifbf17cfafb858106d73bf49af52b5161a265a484
Signed-off-by: San Mehat <san@google.com>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>

1 files changed, 148 insertions, 119 deletions

diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c
index 84b284e3a288..524858597901 100644
--- a/drivers/mmc/host/msm_sdcc.c
+++ b/drivers/mmc/host/msm_sdcc.c
@@ -3,6 +3,7 @@
  *
  *  Copyright (C) 2007 Google Inc,
  *  Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
+ *  Copyright (C) 2009, Code Aurora Forum. All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -47,6 +48,7 @@
 
 #define DRIVER_NAME "msm-sdcc"
 
+#define BUSCLK_TIMEOUT (HZ * 5)
 static unsigned int msmsdcc_fmin = 144000;
 static unsigned int msmsdcc_fmax = 50000000;
 static unsigned int msmsdcc_4bit = 1;
@@ -106,8 +108,6 @@ msmsdcc_start_command(struct msmsdcc_host *host, struct mmc_command *cmd,
 static void
 msmsdcc_request_end(struct msmsdcc_host *host, struct mmc_request *mrq)
 {
-	msmsdcc_writel(host, 0, MMCICOMMAND);
-
 	BUG_ON(host->curr.data);
 
 	host->curr.mrq = NULL;
@@ -119,7 +119,7 @@ msmsdcc_request_end(struct msmsdcc_host *host, struct mmc_request *mrq)
 		mdelay(5);
 
 	if (host->use_bustimer)
-		mod_timer(&host->busclk_timer, jiffies + HZ);
+		mod_timer(&host->busclk_timer, jiffies + BUSCLK_TIMEOUT);
 	/*
 	 * Need to drop the host lock here; mmc_request_done may call
 	 * back into the driver...
@@ -132,7 +132,6 @@ msmsdcc_request_end(struct msmsdcc_host *host, struct mmc_request *mrq)
 static void
 msmsdcc_stop_data(struct msmsdcc_host *host)
 {
-	msmsdcc_writel(host, 0, MMCIDATACTRL);
 	host->curr.data = NULL;
 	host->curr.got_dataend = host->curr.got_datablkend = 0;
 }
@@ -153,6 +152,29 @@ uint32_t msmsdcc_fifo_addr(struct msmsdcc_host *host)
 	return 0;
 }
 
+static inline void
+msmsdcc_start_command_exec(struct msmsdcc_host *host, u32 arg, u32 c) {
+       msmsdcc_writel(host, arg, MMCIARGUMENT);
+       msmsdcc_writel(host, c, MMCICOMMAND);
+}
+
+static void
+msmsdcc_dma_exec_func(struct msm_dmov_cmd *cmd)
+{
+       struct msmsdcc_host *host = (struct msmsdcc_host *)cmd->data;
+
+       writel(host->cmd_timeout, host->base + MMCIDATATIMER);
+       writel((unsigned int)host->curr.xfer_size, host->base + MMCIDATALENGTH);
+       writel(host->cmd_pio_irqmask, host->base + MMCIMASK1);
+       writel(host->cmd_datactrl, host->base + MMCIDATACTRL);
+
+       if (host->cmd_cmd) {
+               msmsdcc_start_command_exec(host,
+                       (u32)host->cmd_cmd->arg, (u32)host->cmd_c);
+       }
+	host->dma.active = 1;
+}
+
 static void
 msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
 			  unsigned int result,
@@ -165,6 +187,8 @@ msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
 	struct mmc_request	*mrq;
 
 	spin_lock_irqsave(&host->lock, flags);
+	host->dma.active = 0;
+
 	mrq = host->curr.mrq;
 	BUG_ON(!mrq);
 
@@ -190,7 +214,6 @@ msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
 		if (!mrq->data->error)
 			mrq->data->error = -EIO;
 	}
-	host->dma.busy = 0;
 	dma_unmap_sg(mmc_dev(host->mmc), host->dma.sg, host->dma.num_ents,
 		     host->dma.dir);
 
@@ -203,6 +226,7 @@ msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
 	}
 
 	host->dma.sg = NULL;
+	host->dma.busy = 0;
 
 	if ((host->curr.got_dataend && host->curr.got_datablkend)
 	     || mrq->data->error) {
@@ -262,6 +286,8 @@ static int msmsdcc_config_dma(struct msmsdcc_host *host, struct mmc_data *data)
 	host->dma.sg = data->sg;
 	host->dma.num_ents = data->sg_len;
 
+       BUG_ON(host->dma.num_ents > NR_SG); /* Prevent memory corruption */
+
 	nc = host->dma.nc;
 
 	switch (host->pdev_id) {
@@ -290,22 +316,15 @@ static int msmsdcc_config_dma(struct msmsdcc_host *host, struct mmc_data *data)
 
 	host->curr.user_pages = 0;
 
-	n = dma_map_sg(mmc_dev(host->mmc), host->dma.sg,
-		       host->dma.num_ents, host->dma.dir);
-
-	if (n != host->dma.num_ents) {
-		pr_err("%s: Unable to map in all sg elements\n",
-		       mmc_hostname(host->mmc));
-		host->dma.sg = NULL;
-		host->dma.num_ents = 0;
-		return -ENOMEM;
-	}
-
 	box = &nc->cmd[0];
 	for (i = 0; i < host->dma.num_ents; i++) {
 		box->cmd = CMD_MODE_BOX;
 
-		if (i == (host->dma.num_ents - 1))
+	/* Initialize sg dma address */
+	sg->dma_address = page_to_dma(mmc_dev(host->mmc), sg_page(sg))
+				+ sg->offset;
+
+	if (i == (host->dma.num_ents - 1))
 			box->cmd |= CMD_LC;
 		rows = (sg_dma_len(sg) % MCI_FIFOSIZE) ?
 			(sg_dma_len(sg) / MCI_FIFOSIZE) + 1 :
@@ -343,13 +362,68 @@ static int msmsdcc_config_dma(struct msmsdcc_host *host, struct mmc_data *data)
 	host->dma.hdr.cmdptr = DMOV_CMD_PTR_LIST |
 			       DMOV_CMD_ADDR(host->dma.cmdptr_busaddr);
 	host->dma.hdr.complete_func = msmsdcc_dma_complete_func;
-	host->dma.hdr.execute_func = NULL;
 
+	n = dma_map_sg(mmc_dev(host->mmc), host->dma.sg,
+			host->dma.num_ents, host->dma.dir);
+/* dsb inside dma_map_sg will write nc out to mem as well */
+
+	if (n != host->dma.num_ents) {
+		printk(KERN_ERR "%s: Unable to map in all sg elements\n",
+			mmc_hostname(host->mmc));
+		host->dma.sg = NULL;
+		host->dma.num_ents = 0;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int
+snoop_cccr_abort(struct mmc_command *cmd)
+{
+	if ((cmd->opcode == 52) &&
+	    (cmd->arg & 0x80000000) &&
+	    (((cmd->arg >> 9) & 0x1ffff) == SDIO_CCCR_ABORT))
+		return 1;
 	return 0;
 }
 
 static void
-msmsdcc_start_data(struct msmsdcc_host *host, struct mmc_data *data)
+msmsdcc_start_command_deferred(struct msmsdcc_host *host,
+				struct mmc_command *cmd, u32 *c)
+{
+	*c |= (cmd->opcode | MCI_CPSM_ENABLE);
+
+	if (cmd->flags & MMC_RSP_PRESENT) {
+		if (cmd->flags & MMC_RSP_136)
+			*c |= MCI_CPSM_LONGRSP;
+		*c |= MCI_CPSM_RESPONSE;
+	}
+
+	if (/*interrupt*/0)
+		*c |= MCI_CPSM_INTERRUPT;
+
+	if ((((cmd->opcode == 17) || (cmd->opcode == 18))  ||
+	     ((cmd->opcode == 24) || (cmd->opcode == 25))) ||
+	      (cmd->opcode == 53))
+		*c |= MCI_CSPM_DATCMD;
+
+	if (cmd == cmd->mrq->stop)
+		*c |= MCI_CSPM_MCIABORT;
+
+	if (snoop_cccr_abort(cmd))
+		*c |= MCI_CSPM_MCIABORT;
+
+	if (host->curr.cmd != NULL) {
+		printk(KERN_ERR "%s: Overlapping command requests\n",
+			mmc_hostname(host->mmc));
+	}
+	host->curr.cmd = cmd;
+}
+
+static void
+msmsdcc_start_data(struct msmsdcc_host *host, struct mmc_data *data,
+			struct mmc_command *cmd, u32 c)
 {
 	unsigned int datactrl, timeout;
 	unsigned long long clks;
@@ -364,13 +438,6 @@ msmsdcc_start_data(struct msmsdcc_host *host, struct mmc_data *data)
 
 	memset(&host->pio, 0, sizeof(host->pio));
 
-	clks = (unsigned long long)data->timeout_ns * host->clk_rate;
-	do_div(clks, NSEC_PER_SEC);
-	timeout = data->timeout_clks + (unsigned int)clks;
-	msmsdcc_writel(host, timeout, MMCIDATATIMER);
-
-	msmsdcc_writel(host, host->curr.xfer_size, MMCIDATALENGTH);
-
 	datactrl = MCI_DPSM_ENABLE | (data->blksz << 4);
 
 	if (!msmsdcc_config_dma(host, data))
@@ -391,56 +458,51 @@ msmsdcc_start_data(struct msmsdcc_host *host, struct mmc_data *data)
 	if (data->flags & MMC_DATA_READ)
 		datactrl |= MCI_DPSM_DIRECTION;
 
-	msmsdcc_writel(host, pio_irqmask, MMCIMASK1);
-	msmsdcc_writel(host, datactrl, MMCIDATACTRL);
+	clks = (unsigned long long)data->timeout_ns * host->clk_rate;
+	do_div(clks, NSEC_PER_SEC);
+	timeout = data->timeout_clks + (unsigned int)clks*2 ;
 
 	if (datactrl & MCI_DPSM_DMAENABLE) {
+		/* Save parameters for the exec function */
+		host->cmd_timeout = timeout;
+		host->cmd_pio_irqmask = pio_irqmask;
+		host->cmd_datactrl = datactrl;
+		host->cmd_cmd = cmd;
+
+		host->dma.hdr.execute_func = msmsdcc_dma_exec_func;
+		host->dma.hdr.data = (void *)host;
 		host->dma.busy = 1;
+
+		if (cmd) {
+			msmsdcc_start_command_deferred(host, cmd, &c);
+			host->cmd_c = c;
+		}
 		msm_dmov_enqueue_cmd(host->dma.channel, &host->dma.hdr);
-	}
-}
+	} else {
+		msmsdcc_writel(host, timeout, MMCIDATATIMER);
 
-static int
-snoop_cccr_abort(struct mmc_command *cmd)
-{
-	if ((cmd->opcode == 52) &&
-	    (cmd->arg & 0x80000000) &&
-	    (((cmd->arg >> 9) & 0x1ffff) == SDIO_CCCR_ABORT))
-		return 1;
-	return 0;
+		msmsdcc_writel(host, host->curr.xfer_size, MMCIDATALENGTH);
+
+		msmsdcc_writel(host, pio_irqmask, MMCIMASK1);
+		msmsdcc_writel(host, datactrl, MMCIDATACTRL);
+
+		if (cmd) {
+			/* Daisy-chain the command if requested */
+			msmsdcc_start_command(host, cmd, c);
+		}
+	}
 }
 
 static void
 msmsdcc_start_command(struct msmsdcc_host *host, struct mmc_command *cmd, u32 c)
 {
-	if (msmsdcc_readl(host, MMCICOMMAND) & MCI_CPSM_ENABLE)
-		msmsdcc_writel(host, 0, MMCICOMMAND);
-
-	c |= cmd->opcode | MCI_CPSM_ENABLE;
-
-	if (cmd->flags & MMC_RSP_PRESENT) {
-		if (cmd->flags & MMC_RSP_136)
-			c |= MCI_CPSM_LONGRSP;
-		c |= MCI_CPSM_RESPONSE;
-	}
-
-	if (cmd->opcode == 17 || cmd->opcode == 18 ||
-	    cmd->opcode == 24 || cmd->opcode == 25 ||
-	    cmd->opcode == 53)
-		c |= MCI_CSPM_DATCMD;
-
 	if (cmd == cmd->mrq->stop)
 		c |= MCI_CSPM_MCIABORT;
 
-	if (snoop_cccr_abort(cmd))
-		c |= MCI_CSPM_MCIABORT;
-
-	host->curr.cmd = cmd;
-
 	host->stats.cmds++;
 
-	msmsdcc_writel(host, cmd->arg, MMCIARGUMENT);
-	msmsdcc_writel(host, c, MMCICOMMAND);
+	msmsdcc_start_command_deferred(host, cmd, &c);
+	msmsdcc_start_command_exec(host, cmd->arg, c);
 }
 
 static void
@@ -611,7 +673,6 @@ static void msmsdcc_do_cmdirq(struct msmsdcc_host *host, uint32_t status)
 	cmd->resp[2] = msmsdcc_readl(host, MMCIRESPONSE2);
 	cmd->resp[3] = msmsdcc_readl(host, MMCIRESPONSE3);
 
-	del_timer(&host->command_timer);
 	if (status & MCI_CMDTIMEOUT) {
 		cmd->error = -ETIMEDOUT;
 	} else if (status & MCI_CMDCRCFAIL &&
@@ -629,16 +690,24 @@ static void msmsdcc_do_cmdirq(struct msmsdcc_host *host, uint32_t status)
 			msmsdcc_request_end(host, cmd->mrq);
 		} else /* host->data == NULL */
 			msmsdcc_request_end(host, cmd->mrq);
-	} else if (!(cmd->data->flags & MMC_DATA_READ))
-		msmsdcc_start_data(host, cmd->data);
+	} else if (cmd->data)
+		if (!(cmd->data->flags & MMC_DATA_READ))
+			msmsdcc_start_data(host, cmd->data,
+						NULL, 0);
 }
 
 static void
 msmsdcc_handle_irq_data(struct msmsdcc_host *host, u32 status,
 			void __iomem *base)
 {
-	struct mmc_data *data = host->curr.data;
+	struct mmc_data *data;
 
+	if (status & (MCI_CMDSENT | MCI_CMDRESPEND | MCI_CMDCRCFAIL |
+	              MCI_CMDTIMEOUT) && host->curr.cmd) {
+		msmsdcc_do_cmdirq(host, status);
+	}
+
+	data = host->curr.data;
 	if (!data)
 		return;
 
@@ -720,11 +789,6 @@ msmsdcc_irq(int irq, void *dev_id)
 
 		msmsdcc_handle_irq_data(host, status, base);
 
-		if (status & (MCI_CMDSENT | MCI_CMDRESPEND | MCI_CMDCRCFAIL |
-			      MCI_CMDTIMEOUT) && host->curr.cmd) {
-			msmsdcc_do_cmdirq(host, status);
-		}
-
 		if (status & MCI_SDIOINTOPER) {
 			cardint = 1;
 			status &= ~MCI_SDIOINTOPER;
@@ -775,9 +839,10 @@ msmsdcc_request(struct mmc_host *mmc, struct mmc_request *mrq)
 		msmsdcc_enable_clocks(host, 1);
 
 	if (mrq->data && mrq->data->flags & MMC_DATA_READ)
-		msmsdcc_start_data(host, mrq->data);
-
-	msmsdcc_start_command(host, mrq->cmd, 0);
+		/* Queue/read data, daisy-chain command when data starts */
+		msmsdcc_start_data(host, mrq->data, mrq->cmd, 0);
+	else
+		msmsdcc_start_command(host, mrq->cmd, 0);
 
 	if (host->cmdpoll && !msmsdcc_spin_on_status(host,
 				MCI_CMDRESPEND|MCI_CMDCRCFAIL|MCI_CMDTIMEOUT,
@@ -790,7 +855,6 @@ msmsdcc_request(struct mmc_host *mmc, struct mmc_request *mrq)
 		host->stats.cmdpoll_hits++;
 	} else {
 		host->stats.cmdpoll_misses++;
-		mod_timer(&host->command_timer, jiffies + HZ);
 	}
 	spin_unlock_irqrestore(&host->lock, flags);
 }
@@ -943,42 +1007,6 @@ msmsdcc_busclk_expired(unsigned long _data)
 	spin_unlock_irqrestore(&host->lock, flags);
 }
 
-/*
- * called when a command expires.
- * Dump some debugging, and then error
- * out the transaction.
- */
-static void
-msmsdcc_command_expired(unsigned long _data)
-{
-	struct msmsdcc_host	*host = (struct msmsdcc_host *) _data;
-	struct mmc_request	*mrq;
-	unsigned long		flags;
-
-	spin_lock_irqsave(&host->lock, flags);
-	mrq = host->curr.mrq;
-
-	if (!mrq) {
-		spin_unlock_irqrestore(&host->lock, flags);
-		return;
-	}
-
-	pr_err("%s: Controller lockup detected\n",
-	       mmc_hostname(host->mmc));
-	mrq->cmd->error = -ETIMEDOUT;
-	msmsdcc_stop_data(host);
-
-	msmsdcc_writel(host, 0, MMCICOMMAND);
-
-	host->curr.mrq = NULL;
-	host->curr.cmd = NULL;
-
-	if (host->clks_on)
-		msmsdcc_enable_clocks(host, 0);
-	spin_unlock_irqrestore(&host->lock, flags);
-	mmc_request_done(host->mmc, mrq);
-}
-
 static int
 msmsdcc_init_dma(struct msmsdcc_host *host)
 {
@@ -1078,6 +1106,7 @@ msmsdcc_probe(struct platform_device *pdev)
 	host->pdev_id = pdev->id;
 	host->plat = plat;
 	host->mmc = mmc;
+	host->curr.cmd = NULL;
 
 	host->cmdpoll = 1;
 
@@ -1194,14 +1223,6 @@ msmsdcc_probe(struct platform_device *pdev)
 		host->eject = !host->oldstat;
 	}
 
-	/*
-	 * Setup a command timer. We currently need this due to
-	 * some 'strange' timeout / error handling situations.
-	 */
-	init_timer(&host->command_timer);
-	host->command_timer.data = (unsigned long) host;
-	host->command_timer.function = msmsdcc_command_expired;
-
 	init_timer(&host->busclk_timer);
 	host->busclk_timer.data = (unsigned long) host;
 	host->busclk_timer.function = msmsdcc_busclk_expired;
@@ -1243,7 +1264,7 @@ msmsdcc_probe(struct platform_device *pdev)
 		pr_info("%s: Polling status mode enabled\n", mmc_hostname(mmc));
 
 	if (host->use_bustimer)
-		mod_timer(&host->busclk_timer, jiffies + HZ);
+		mod_timer(&host->busclk_timer, jiffies + BUSCLK_TIMEOUT);
 	return 0;
  cmd_irq_free:
 	free_irq(cmd_irqres->start, host);
@@ -1267,10 +1288,14 @@ msmsdcc_suspend(struct platform_device *dev, pm_message_t state)
 {
 	struct mmc_host *mmc = mmc_get_drvdata(dev);
 	int rc = 0;
+	unsigned long flags;
 
 	if (mmc) {
 		struct msmsdcc_host *host = mmc_priv(mmc);
 
+		if (host->use_bustimer)
+			del_timer_sync(&host->busclk_timer);
+		spin_lock_irqsave(&host->lock, flags);
 		if (host->stat_irq)
 			disable_irq(host->stat_irq);
 
@@ -1282,6 +1307,7 @@ msmsdcc_suspend(struct platform_device *dev, pm_message_t state)
 			if (host->clks_on)
 				msmsdcc_enable_clocks(host, 0);
 		}
+		spin_unlock_irqrestore(&host->lock, flags);
 	}
 	return rc;
 }
@@ -1300,6 +1326,9 @@ msmsdcc_resume(struct platform_device *dev)
 		if (!host->clks_on)
 			msmsdcc_enable_clocks(host, 1);
 
+		if (host->use_bustimer)
+			mod_timer(&host->busclk_timer, jiffies + BUSCLK_TIMEOUT);
+
 		msmsdcc_writel(host, host->saved_irq0mask, MMCIMASK0);
 
 		spin_unlock_irqrestore(&host->lock, flags);