[PATCH 0/6] mmc: dw_mmc: misc fixes and improvements

[PATCH 0/6] mmc: dw_mmc: misc fixes and improvements

[James Hogan]

Misc improvements and fixes for the Synopsys DesignWare MMC driver:

[PATCH 1/6] mmc: dw_mmc: clear TXDR/RXDR ints before enabling
	fixes a failure to probe the next card after an unplug
[PATCH 2/6] mmc: dw_mmc: fix race with request and removal
	improves spinlock protection
[PATCH 3/6] mmc: dw_mmc: convert card tasklet to workqueue
	to allow platform callbacks to sleep
[PATCH 4/6] mmc: dw_mmc: brackets in register access macros
	just a small tidyup patch
[PATCH 5/6] mmc: dw_mmc: don't hard code fifo depth, fix usage
	improve detection of fifo depth
[PATCH 6/6] mmc: dw_mmc: handle unaligned buffers and sizes
	fix some mmc_test failures wrt unaligned buffer/sizes
 
 drivers/mmc/host/dw_mmc.c  |  398 ++++++++++++++++++++++++++++++++++----------
 drivers/mmc/host/dw_mmc.h  |   17 +-
 include/linux/mmc/dw_mmc.h |   20 ++-
 3 files changed, 340 insertions(+), 95 deletions(-)

[PATCH 1/6] mmc: dw_mmc: clear TXDR/RXDR ints before enabling

[James Hogan]

DMA is only used for transactions exceeding a certain length, otherwise
PIO is used. The TXDR and RXDR interrupts are masked when in DMA mode
but still fire. When switching to PIO mode (e.g. to get SCR field when
an SD card is inserted) these interrupts are not cleared and so they
trigger the ISR as soon as they are unmasked. If the previous DMA did a
write, then the ISR will handle the TXDR interrupt even if the
transaction is a read, completing the transaction without modifying the
read buffer.

This is fixed primarily by clearing these two interrupts before
unmasking them when setting up PIO mode, and also by making the ISR more
robust by only handling TXDR/RXDR in the correct read/write direction.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 drivers/mmc/host/dw_mmc.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 22be372..08c0592 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -497,6 +497,7 @@ static void dw_mci_submit_data(struct dw_mci *host, struct mmc_data *data)
 		else
 			host->dir_status = DW_MCI_SEND_STATUS;
 
+		mci_writel(host, RINTSTS, SDMMC_INT_TXDR | SDMMC_INT_RXDR);
 		temp = mci_readl(host, INTMASK);
 		temp |= SDMMC_INT_TXDR | SDMMC_INT_RXDR;
 		mci_writel(host, INTMASK, temp);
@@ -1230,13 +1231,13 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
 
 		if (pending & SDMMC_INT_RXDR) {
 			mci_writel(host, RINTSTS, SDMMC_INT_RXDR);
-			if (host->sg)
+			if (host->dir_status == DW_MCI_RECV_STATUS && host->sg)
 				dw_mci_read_data_pio(host);
 		}
 
 		if (pending & SDMMC_INT_TXDR) {
 			mci_writel(host, RINTSTS, SDMMC_INT_TXDR);
-			if (host->sg)
+			if (host->dir_status == DW_MCI_SEND_STATUS && host->sg)
 				dw_mci_write_data_pio(host);
 		}
 
-- 
1.7.2.3

[PATCH 2/6] mmc: dw_mmc: fix race with request and removal

[James Hogan]

When a request is made, the card presence is checked and the request is
queued. These two parts must be atomic with respect to card removal, or
a card removal could be handled in between, and the new request wouldn't
get cancelled until another card was inserted. Therefore move the
spinlock protection from dw_mci_queue_request() up into dw_mci_request()
to cover the presence check.

Note that the test_bit() used for the presence check isn't atomic
itself, so should have been protected by a spinlock anyway.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 drivers/mmc/host/dw_mmc.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 08c0592..c4bddf6 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -625,13 +625,13 @@ static void dw_mci_start_request(struct dw_mci *host,
 		host->stop_cmdr = dw_mci_prepare_command(slot->mmc, mrq->stop);
 }
 
+/* must be called with host->lock held */
 static void dw_mci_queue_request(struct dw_mci *host, struct dw_mci_slot *slot,
 				 struct mmc_request *mrq)
 {
 	dev_vdbg(&slot->mmc->class_dev, "queue request: state=%d\n",
 		 host->state);
 
-	spin_lock_bh(&host->lock);
 	slot->mrq = mrq;
 
 	if (host->state == STATE_IDLE) {
@@ -640,8 +640,6 @@ static void dw_mci_queue_request(struct dw_mci *host, struct dw_mci_slot *slot,
 	} else {
 		list_add_tail(&slot->queue_node, &host->queue);
 	}
-
-	spin_unlock_bh(&host->lock);
 }
 
 static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
@@ -651,14 +649,23 @@ static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 
 	WARN_ON(slot->mrq);
 
+	/*
+	 * The check for card presence and queueing of the request must be
+	 * atomic, otherwise the card could be removed in between and the
+	 * request wouldn't fail until another card was inserted.
+	 */
+	spin_lock_bh(&host->lock);
+
 	if (!test_bit(DW_MMC_CARD_PRESENT, &slot->flags)) {
+		spin_unlock_bh(&host->lock);
 		mrq->cmd->error = -ENOMEDIUM;
 		mmc_request_done(mmc, mrq);
 		return;
 	}
 
-	/* We don't support multiple blocks of weird lengths. */
 	dw_mci_queue_request(host, slot, mrq);
+
+	spin_unlock_bh(&host->lock);
 }
 
 static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
-- 
1.7.2.3

[PATCH 3/6] mmc: dw_mmc: convert card tasklet to workqueue

[James Hogan]

Convert the card insert/remove tasklet to a workqueue, and call the
setpower platform specific callback without the spinlock held. This
means neither of the setpower or get_cd callbacks are called from atomic
context which allows them to sleep.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 drivers/mmc/host/dw_mmc.c  |   50 +++++++++++++++++++++++++++----------------
 include/linux/mmc/dw_mmc.h |    2 +-
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index c4bddf6..3f610d5 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -33,6 +33,7 @@
 #include <linux/mmc/dw_mmc.h>
 #include <linux/bitops.h>
 #include <linux/regulator/consumer.h>
+#include <linux/workqueue.h>
 
 #include "dw_mmc.h"
 
@@ -100,6 +101,8 @@ struct dw_mci_slot {
 	int			last_detect_state;
 };
 
+static struct workqueue_struct *dw_mci_card_workqueue;
+
 #if defined(CONFIG_DEBUG_FS)
 static int dw_mci_req_show(struct seq_file *s, void *v)
 {
@@ -1255,7 +1258,7 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
 
 		if (pending & SDMMC_INT_CD) {
 			mci_writel(host, RINTSTS, SDMMC_INT_CD);
-			tasklet_schedule(&host->card_tasklet);
+			queue_work(dw_mci_card_workqueue, &host->card_work);
 		}
 
 	} while (pass_count++ < 5);
@@ -1274,9 +1277,9 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void dw_mci_tasklet_card(unsigned long data)
+static void dw_mci_work_routine_card(struct work_struct *work)
 {
-	struct dw_mci *host = (struct dw_mci *)data;
+	struct dw_mci *host = container_of(work, struct dw_mci, card_work);
 	int i;
 
 	for (i = 0; i < host->num_slots; i++) {
@@ -1288,22 +1291,21 @@ static void dw_mci_tasklet_card(unsigned long data)
 
 		present = dw_mci_get_cd(mmc);
 		while (present != slot->last_detect_state) {
-			spin_lock(&host->lock);
-
 			dev_dbg(&slot->mmc->class_dev, "card %s\n",
 				present ? "inserted" : "removed");
 
+			/* Power up slot (before spin_lock, may sleep) */
+			if (present != 0 && host->pdata->setpower)
+				host->pdata->setpower(slot->id, mmc->ocr_avail);
+
+			spin_lock_bh(&host->lock);
+
 			/* Card change detected */
 			slot->last_detect_state = present;
 
-			/* Power up slot */
-			if (present != 0) {
-				if (host->pdata->setpower)
-					host->pdata->setpower(slot->id,
-							      mmc->ocr_avail);
-
+			/* Mark card as present if applicable */
+			if (present != 0)
 				set_bit(DW_MMC_CARD_PRESENT, &slot->flags);
-			}
 
 			/* Clean up queue if present */
 			mrq = slot->mrq;
@@ -1353,8 +1355,6 @@ static void dw_mci_tasklet_card(unsigned long data)
 
 			/* Power down slot */
 			if (present == 0) {
-				if (host->pdata->setpower)
-					host->pdata->setpower(slot->id, 0);
 				clear_bit(DW_MMC_CARD_PRESENT, &slot->flags);
 
 				/*
@@ -1376,7 +1376,12 @@ static void dw_mci_tasklet_card(unsigned long data)
 
 			}
 
-			spin_unlock(&host->lock);
+			spin_unlock_bh(&host->lock);
+
+			/* Power down slot (after spin_unlock, may sleep) */
+			if (present == 0 && host->pdata->setpower)
+				host->pdata->setpower(slot->id, 0);
+
 			present = dw_mci_get_cd(mmc);
 		}
 
@@ -1476,7 +1481,7 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
 	 * Card may have been plugged in prior to boot so we
 	 * need to run the detect tasklet
 	 */
-	tasklet_schedule(&host->card_tasklet);
+	queue_work(dw_mci_card_workqueue, &host->card_work);
 
 	return 0;
 }
@@ -1665,12 +1670,15 @@ static int dw_mci_probe(struct platform_device *pdev)
 	mci_writel(host, CLKSRC, 0);
 
 	tasklet_init(&host->tasklet, dw_mci_tasklet_func, (unsigned long)host);
-	tasklet_init(&host->card_tasklet,
-		     dw_mci_tasklet_card, (unsigned long)host);
+	dw_mci_card_workqueue = alloc_workqueue("dw-mci-card",
+			WQ_MEM_RECLAIM | WQ_NON_REENTRANT, 1);
+	if (!dw_mci_card_workqueue)
+		goto err_dmaunmap;
+	INIT_WORK(&host->card_work, dw_mci_work_routine_card);
 
 	ret = request_irq(irq, dw_mci_interrupt, 0, "dw-mci", host);
 	if (ret)
-		goto err_dmaunmap;
+		goto err_workqueue;
 
 	platform_set_drvdata(pdev, host);
 
@@ -1714,6 +1722,9 @@ err_init_slot:
 	}
 	free_irq(irq, host);
 
+err_workqueue:
+	destroy_workqueue(dw_mci_card_workqueue);
+
 err_dmaunmap:
 	if (host->use_dma && host->dma_ops->exit)
 		host->dma_ops->exit(host);
@@ -1753,6 +1764,7 @@ static int __exit dw_mci_remove(struct platform_device *pdev)
 	mci_writel(host, CLKSRC, 0);
 
 	free_irq(platform_get_irq(pdev, 0), host);
+	destroy_workqueue(dw_mci_card_workqueue);
 	dma_free_coherent(&pdev->dev, PAGE_SIZE, host->sg_cpu, host->sg_dma);
 
 	if (host->use_dma && host->dma_ops->exit)
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index 55d9909..dea4847 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -131,7 +131,7 @@ struct dw_mci {
 	u32			stop_cmdr;
 	u32			dir_status;
 	struct tasklet_struct	tasklet;
-	struct tasklet_struct	card_tasklet;
+	struct work_struct	card_work;
 	unsigned long		pending_events;
 	unsigned long		completed_events;
 	enum dw_mci_state	state;
-- 
1.7.2.3

[PATCH 4/6] mmc: dw_mmc: brackets in register access macros

[James Hogan]

Add brackets around use of the dev argument to the
mci_{read,write}{w,l,q}() macros, for extra safety.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 drivers/mmc/host/dw_mmc.h |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 23c662a..bb9e5de 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -134,22 +134,22 @@
 
 /* Register access macros */
 #define mci_readl(dev, reg)			\
-	__raw_readl(dev->regs + SDMMC_##reg)
+	__raw_readl((dev)->regs + SDMMC_##reg)
 #define mci_writel(dev, reg, value)			\
-	__raw_writel((value), dev->regs + SDMMC_##reg)
+	__raw_writel((value), (dev)->regs + SDMMC_##reg)
 
 /* 16-bit FIFO access macros */
 #define mci_readw(dev, reg)			\
-	__raw_readw(dev->regs + SDMMC_##reg)
+	__raw_readw((dev)->regs + SDMMC_##reg)
 #define mci_writew(dev, reg, value)			\
-	__raw_writew((value), dev->regs + SDMMC_##reg)
+	__raw_writew((value), (dev)->regs + SDMMC_##reg)
 
 /* 64-bit FIFO access macros */
 #ifdef readq
 #define mci_readq(dev, reg)			\
-	__raw_readq(dev->regs + SDMMC_##reg)
+	__raw_readq((dev)->regs + SDMMC_##reg)
 #define mci_writeq(dev, reg, value)			\
-	__raw_writeq((value), dev->regs + SDMMC_##reg)
+	__raw_writeq((value), (dev)->regs + SDMMC_##reg)
 #else
 /*
  * Dummy readq implementation for architectures that don't define it.
@@ -160,9 +160,9 @@
  * rest of the code free from ifdefs.
  */
 #define mci_readq(dev, reg)			\
-	(*(volatile u64 __force *)(dev->regs + SDMMC_##reg))
+	(*(volatile u64 __force *)((dev)->regs + SDMMC_##reg))
 #define mci_writeq(dev, reg, value)			\
-	(*(volatile u64 __force *)(dev->regs + SDMMC_##reg) = value)
+	(*(volatile u64 __force *)((dev)->regs + SDMMC_##reg) = (value))
 #endif
 
 #endif /* _DW_MMC_H_ */
-- 
1.7.2.3

[PATCH 5/6] mmc: dw_mmc: don't hard code fifo depth, fix usage

[James Hogan]

The FIFO_DEPTH hardware configuration parameter can be found from the
power-on value of RX_WMark in the FIFOTH register. This is used to
initialise the watermarks, but when calculating the number of free fifo
spaces a preprocessor definition is used which is hard coded to 32.

Fix reading the value out of FIFOTH (the default value in the RX_WMark
field is FIFO_DEPTH-1 not FIFO_DEPTH). Allow the fifo depth to be
overriden by platform data (since a bootloader may have changed FIFOTH
making auto-detection unreliable). Store the fifo_depth for later use.
Also fix the calculation to find the number of free bytes in the fifo to
include the fifo depth in the left shift by the data shift, since the
fifo depth is measured in fifo items not bytes.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 drivers/mmc/host/dw_mmc.c  |   23 ++++++++++++++++++-----
 drivers/mmc/host/dw_mmc.h  |    1 -
 include/linux/mmc/dw_mmc.h |    8 ++++++++
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 3f610d5..3832312 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1116,8 +1116,8 @@ static void dw_mci_write_data_pio(struct dw_mci *host)
 	unsigned int nbytes = 0, len;
 
 	do {
-		len = SDMMC_FIFO_SZ -
-			(SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift);
+		len = (host->fifo_depth -
+			SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift;
 		if (offset + len <= sg->length) {
 			host->push_data(host, (void *)(buf + offset), len);
 
@@ -1659,8 +1659,19 @@ static int dw_mci_probe(struct platform_device *pdev)
 	 * FIFO threshold settings  RxMark  = fifo_size / 2 - 1,
 	 *                          Tx Mark = fifo_size / 2 DMA Size = 8
 	 */
-	fifo_size = mci_readl(host, FIFOTH);
-	fifo_size = (fifo_size >> 16) & 0x7ff;
+	if (!host->pdata->fifo_depth) {
+		/*
+		 * Power-on value of RX_WMark is FIFO_DEPTH-1, but this may
+		 * have been overwritten by the bootloader, just like we're
+		 * about to do, so if you know the value for your hardware, you
+		 * should put it in the platform data.
+		 */
+		fifo_size = mci_readl(host, FIFOTH);
+		fifo_size = 1 + ((fifo_size >> 16) & 0x7ff);
+	} else {
+		fifo_size = host->pdata->fifo_depth;
+	}
+	host->fifo_depth = fifo_size;
 	host->fifoth_val = ((0x2 << 28) | ((fifo_size/2 - 1) << 16) |
 			((fifo_size/2) << 0));
 	mci_writel(host, FIFOTH, host->fifoth_val);
@@ -1707,7 +1718,9 @@ static int dw_mci_probe(struct platform_device *pdev)
 	mci_writel(host, CTRL, SDMMC_CTRL_INT_ENABLE); /* Enable mci interrupt */
 
 	dev_info(&pdev->dev, "DW MMC controller at irq %d, "
-		 "%d bit host data width\n", irq, width);
+		 "%d bit host data width, "
+		 "%u deep fifo\n",
+		 irq, width, fifo_size);
 	if (host->quirks & DW_MCI_QUIRK_IDMAC_DTO)
 		dev_info(&pdev->dev, "Internal DMAC interrupt fix enabled.\n");
 
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index bb9e5de..027d377 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -118,7 +118,6 @@
 #define SDMMC_CMD_INDX(n)		((n) & 0x1F)
 /* Status register defines */
 #define SDMMC_GET_FCNT(x)		(((x)>>17) & 0x1FF)
-#define SDMMC_FIFO_SZ			32
 /* Internal DMAC interrupt defines */
 #define SDMMC_IDMAC_INT_AI		BIT(9)
 #define SDMMC_IDMAC_INT_NI		BIT(8)
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index dea4847..01db1a0 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -74,6 +74,7 @@ struct mmc_data;
  * @pdev: Platform device associated with the MMC controller.
  * @pdata: Platform data associated with the MMC controller.
  * @slot: Slots sharing this MMC controller.
+ * @fifo_depth: depth of FIFO.
  * @data_shift: log2 of FIFO item size.
  * @push_data: Pointer to FIFO push function.
  * @pull_data: Pointer to FIFO pull function.
@@ -146,6 +147,7 @@ struct dw_mci {
 	struct dw_mci_slot	*slot[MAX_MCI_SLOTS];
 
 	/* FIFO push and pull */
+	int			fifo_depth;
 	int			data_shift;
 	void (*push_data)(struct dw_mci *host, void *buf, int cnt);
 	void (*pull_data)(struct dw_mci *host, void *buf, int cnt);
@@ -196,6 +198,12 @@ struct dw_mci_board {
 	unsigned int bus_hz; /* Bus speed */
 
 	unsigned int caps;	/* Capabilities */
+	/*
+	 * Override fifo depth. If 0, autodetect it from the FIFOTH register,
+	 * but note that this may not be reliable after a bootloader has used
+	 * it.
+	 */
+	unsigned int fifo_depth;
 
 	/* delay in mS before detecting cards after interrupt */
 	u32 detect_delay_ms;
-- 
1.7.2.3

[PATCH 6/6] mmc: dw_mmc: handle unaligned buffers and sizes

[James Hogan]

Update functions for PIO pushing and pulling data to and from the FIFO
so that they can handle unaligned output buffers and unaligned buffer
lengths. This makes more of the tests in mmc_test pass.

Unaligned lengths in pulls are handled by reading the full FIFO item,
and storing the remaining bytes in a small internal buffer (part_buf).
The next data pull will copy data out of this buffer first before
accessing the FIFO again. Similarly, for pushes the final bytes that
don't fill a FIFO item are stored in the part_buf (or sent anyway if
it's the last transfer), and then the part_buf is included at the
beginning of the next buffer pushed.

Unaligned buffers in pulls are handled specially if the architecture
cannot do efficient unaligned accesses, by reading FIFO items into a
aligned local buffer, and memcpy'ing them into the output buffer, again
storing any remaining bytes in the internal buffer. Similarly for pushes
the buffer is memcpy'd into an aligned local buffer then written to the
FIFO.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 drivers/mmc/host/dw_mmc.c  |  309 ++++++++++++++++++++++++++++++++++++--------
 include/linux/mmc/dw_mmc.h |   10 ++
 2 files changed, 262 insertions(+), 57 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 3832312..10b6979 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -495,6 +495,8 @@ static void dw_mci_submit_data(struct dw_mci *host, struct mmc_data *data)
 	if (dw_mci_submit_data_dma(host, data)) {
 		host->sg = data->sg;
 		host->pio_offset = 0;
+		host->part_buf_start = 0;
+		host->part_buf_count = 0;
 		if (data->flags & MMC_DATA_READ)
 			host->dir_status = DW_MCI_RECV_STATUS;
 		else
@@ -957,84 +959,278 @@ unlock:
 
 }
 
-static void dw_mci_push_data16(struct dw_mci *host, void *buf, int cnt)
+/* push final bytes to part_buf, only use during push */
+static void dw_mci_set_part_bytes(struct dw_mci *host, void *buf, int cnt)
 {
-	u16 *pdata = (u16 *)buf;
+	memcpy((void *)&host->part_buf, buf, cnt);
+	host->part_buf_count = cnt;
+}
 
-	WARN_ON(cnt % 2 != 0);
+/* append bytes to part_buf, only use during push */
+static int dw_mci_push_part_bytes(struct dw_mci *host, void *buf, int cnt)
+{
+	cnt = min(cnt, (1 << host->data_shift) - host->part_buf_count);
+	memcpy((void *)&host->part_buf + host->part_buf_count, buf, cnt);
+	host->part_buf_count += cnt;
+	return cnt;
+}
 
-	cnt = cnt >> 1;
-	while (cnt > 0) {
-		mci_writew(host, DATA, *pdata++);
-		cnt--;
+/* pull first bytes from part_buf, only use during pull */
+static int dw_mci_pull_part_bytes(struct dw_mci *host, void *buf, int cnt)
+{
+	cnt = min(cnt, (int)host->part_buf_count);
+	if (cnt) {
+		memcpy(buf, (void *)&host->part_buf + host->part_buf_start,
+		       cnt);
+		host->part_buf_count -= cnt;
+		host->part_buf_start += cnt;
 	}
+	return cnt;
 }
 
-static void dw_mci_pull_data16(struct dw_mci *host, void *buf, int cnt)
+/* pull final bytes from the part_buf, assuming it's just been filled */
+static void dw_mci_pull_final_bytes(struct dw_mci *host, void *buf, int cnt)
 {
-	u16 *pdata = (u16 *)buf;
+	memcpy(buf, &host->part_buf, cnt);
+	host->part_buf_start = cnt;
+	host->part_buf_count = (1 << host->data_shift) - cnt;
+}
 
-	WARN_ON(cnt % 2 != 0);
+static void dw_mci_push_data16(struct dw_mci *host, void *buf, int cnt)
+{
+	/* try and push anything in the part_buf */
+	if (unlikely(host->part_buf_count)) {
+		int len = dw_mci_push_part_bytes(host, buf, cnt);
+		buf += len;
+		cnt -= len;
+		if (!sg_next(host->sg) || host->part_buf_count == 2) {
+			mci_writew(host, DATA, host->part_buf16);
+			host->part_buf_count = 0;
+		}
+	}
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x1)) {
+		while (cnt >= 2) {
+			u16 aligned_buf[64];
+			int len = min(cnt & -2, (int)sizeof(aligned_buf));
+			int items = len >> 1;
+			int i;
+			/* memcpy from input buffer into aligned buffer */
+			memcpy(aligned_buf, buf, len);
+			buf += len;
+			cnt -= len;
+			/* push data from aligned buffer into fifo */
+			for (i = 0; i < items; ++i)
+				mci_writew(host, DATA, aligned_buf[i]);
+		}
+	} else
+#endif
+	{
+		u16 *pdata = buf;
+		for (; cnt >= 2; cnt -= 2)
+			mci_writew(host, DATA, *pdata++);
+		buf = pdata;
+	}
+	/* put anything remaining in the part_buf */
+	if (cnt) {
+		dw_mci_set_part_bytes(host, buf, cnt);
+		if (!sg_next(host->sg))
+			mci_writew(host, DATA, host->part_buf16);
+	}
+}
 
-	cnt = cnt >> 1;
-	while (cnt > 0) {
-		*pdata++ = mci_readw(host, DATA);
-		cnt--;
+static void dw_mci_pull_data16(struct dw_mci *host, void *buf, int cnt)
+{
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x1)) {
+		while (cnt >= 2) {
+			/* pull data from fifo into aligned buffer */
+			u16 aligned_buf[64];
+			int len = min(cnt & -2, (int)sizeof(aligned_buf));
+			int items = len >> 1;
+			int i;
+			for (i = 0; i < items; ++i)
+				aligned_buf[i] = mci_readw(host, DATA);
+			/* memcpy from aligned buffer into output buffer */
+			memcpy(buf, aligned_buf, len);
+			buf += len;
+			cnt -= len;
+		}
+	} else
+#endif
+	{
+		u16 *pdata = buf;
+		for (; cnt >= 2; cnt -= 2)
+			*pdata++ = mci_readw(host, DATA);
+		buf = pdata;
+	}
+	if (cnt) {
+		host->part_buf16 = mci_readw(host, DATA);
+		dw_mci_pull_final_bytes(host, buf, cnt);
 	}
 }
 
 static void dw_mci_push_data32(struct dw_mci *host, void *buf, int cnt)
 {
-	u32 *pdata = (u32 *)buf;
-
-	WARN_ON(cnt % 4 != 0);
-	WARN_ON((unsigned long)pdata & 0x3);
-
-	cnt = cnt >> 2;
-	while (cnt > 0) {
-		mci_writel(host, DATA, *pdata++);
-		cnt--;
+	/* try and push anything in the part_buf */
+	if (unlikely(host->part_buf_count)) {
+		int len = dw_mci_push_part_bytes(host, buf, cnt);
+		buf += len;
+		cnt -= len;
+		if (!sg_next(host->sg) || host->part_buf_count == 4) {
+			mci_writel(host, DATA, host->part_buf32);
+			host->part_buf_count = 0;
+		}
+	}
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x3)) {
+		while (cnt >= 4) {
+			u32 aligned_buf[32];
+			int len = min(cnt & -4, (int)sizeof(aligned_buf));
+			int items = len >> 2;
+			int i;
+			/* memcpy from input buffer into aligned buffer */
+			memcpy(aligned_buf, buf, len);
+			buf += len;
+			cnt -= len;
+			/* push data from aligned buffer into fifo */
+			for (i = 0; i < items; ++i)
+				mci_writel(host, DATA, aligned_buf[i]);
+		}
+	} else
+#endif
+	{
+		u32 *pdata = buf;
+		for (; cnt >= 4; cnt -= 4)
+			mci_writel(host, DATA, *pdata++);
+		buf = pdata;
+	}
+	/* put anything remaining in the part_buf */
+	if (cnt) {
+		dw_mci_set_part_bytes(host, buf, cnt);
+		if (!sg_next(host->sg))
+			mci_writel(host, DATA, host->part_buf32);
 	}
 }
 
 static void dw_mci_pull_data32(struct dw_mci *host, void *buf, int cnt)
 {
-	u32 *pdata = (u32 *)buf;
-
-	WARN_ON(cnt % 4 != 0);
-	WARN_ON((unsigned long)pdata & 0x3);
-
-	cnt = cnt >> 2;
-	while (cnt > 0) {
-		*pdata++ = mci_readl(host, DATA);
-		cnt--;
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x3)) {
+		while (cnt >= 4) {
+			/* pull data from fifo into aligned buffer */
+			u32 aligned_buf[32];
+			int len = min(cnt & -4, (int)sizeof(aligned_buf));
+			int items = len >> 2;
+			int i;
+			for (i = 0; i < items; ++i)
+				aligned_buf[i] = mci_readl(host, DATA);
+			/* memcpy from aligned buffer into output buffer */
+			memcpy(buf, aligned_buf, len);
+			buf += len;
+			cnt -= len;
+		}
+	} else
+#endif
+	{
+		u32 *pdata = buf;
+		for (; cnt >= 4; cnt -= 4)
+			*pdata++ = mci_readl(host, DATA);
+		buf = pdata;
+	}
+	if (cnt) {
+		host->part_buf32 = mci_readl(host, DATA);
+		dw_mci_pull_final_bytes(host, buf, cnt);
 	}
 }
 
 static void dw_mci_push_data64(struct dw_mci *host, void *buf, int cnt)
 {
-	u64 *pdata = (u64 *)buf;
-
-	WARN_ON(cnt % 8 != 0);
-
-	cnt = cnt >> 3;
-	while (cnt > 0) {
-		mci_writeq(host, DATA, *pdata++);
-		cnt--;
+	/* try and push anything in the part_buf */
+	if (unlikely(host->part_buf_count)) {
+		int len = dw_mci_push_part_bytes(host, buf, cnt);
+		buf += len;
+		cnt -= len;
+		if (!sg_next(host->sg) || host->part_buf_count == 8) {
+			mci_writew(host, DATA, host->part_buf);
+			host->part_buf_count = 0;
+		}
+	}
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x7)) {
+		while (cnt >= 8) {
+			u64 aligned_buf[16];
+			int len = min(cnt & -8, (int)sizeof(aligned_buf));
+			int items = len >> 3;
+			int i;
+			/* memcpy from input buffer into aligned buffer */
+			memcpy(aligned_buf, buf, len);
+			buf += len;
+			cnt -= len;
+			/* push data from aligned buffer into fifo */
+			for (i = 0; i < items; ++i)
+				mci_writeq(host, DATA, aligned_buf[i]);
+		}
+	} else
+#endif
+	{
+		u64 *pdata = buf;
+		for (; cnt >= 8; cnt -= 8)
+			mci_writeq(host, DATA, *pdata++);
+		buf = pdata;
+	}
+	/* put anything remaining in the part_buf */
+	if (cnt) {
+		dw_mci_set_part_bytes(host, buf, cnt);
+		if (!sg_next(host->sg))
+			mci_writeq(host, DATA, host->part_buf);
 	}
 }
 
 static void dw_mci_pull_data64(struct dw_mci *host, void *buf, int cnt)
 {
-	u64 *pdata = (u64 *)buf;
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (unlikely((unsigned long)buf & 0x7)) {
+		while (cnt >= 8) {
+			/* pull data from fifo into aligned buffer */
+			u64 aligned_buf[16];
+			int len = min(cnt & -8, (int)sizeof(aligned_buf));
+			int items = len >> 3;
+			int i;
+			for (i = 0; i < items; ++i)
+				aligned_buf[i] = mci_readq(host, DATA);
+			/* memcpy from aligned buffer into output buffer */
+			memcpy(buf, aligned_buf, len);
+			buf += len;
+			cnt -= len;
+		}
+	} else
+#endif
+	{
+		u64 *pdata = buf;
+		for (; cnt >= 8; cnt -= 8)
+			*pdata++ = mci_readq(host, DATA);
+		buf = pdata;
+	}
+	if (cnt) {
+		host->part_buf = mci_readq(host, DATA);
+		dw_mci_pull_final_bytes(host, buf, cnt);
+	}
+}
+
+static void dw_mci_pull_data(struct dw_mci *host, void *buf, int cnt)
+{
+	int len;
 
-	WARN_ON(cnt % 8 != 0);
+	/* get remaining partial bytes */
+	len = dw_mci_pull_part_bytes(host, buf, cnt);
+	if (unlikely(len == cnt))
+		return;
+	buf += len;
+	cnt -= len;
 
-	cnt = cnt >> 3;
-	while (cnt > 0) {
-		*pdata++ = mci_readq(host, DATA);
-		cnt--;
-	}
+	/* get the rest of the data */
+	host->pull_data(host, buf, cnt);
 }
 
 static void dw_mci_read_data_pio(struct dw_mci *host)
@@ -1048,9 +1244,10 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 	unsigned int nbytes = 0, len;
 
 	do {
-		len = SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift;
+		len = host->part_buf_count +
+			(SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift);
 		if (offset + len <= sg->length) {
-			host->pull_data(host, (void *)(buf + offset), len);
+			dw_mci_pull_data(host, (void *)(buf + offset), len);
 
 			offset += len;
 			nbytes += len;
@@ -1066,8 +1263,8 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 			}
 		} else {
 			unsigned int remaining = sg->length - offset;
-			host->pull_data(host, (void *)(buf + offset),
-					remaining);
+			dw_mci_pull_data(host, (void *)(buf + offset),
+					 remaining);
 			nbytes += remaining;
 
 			flush_dcache_page(sg_page(sg));
@@ -1077,7 +1274,7 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 
 			offset = len - remaining;
 			buf = sg_virt(sg);
-			host->pull_data(host, buf, offset);
+			dw_mci_pull_data(host, buf, offset);
 			nbytes += offset;
 		}
 
@@ -1094,7 +1291,6 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
 			return;
 		}
 	} while (status & SDMMC_INT_RXDR); /*if the RXDR is ready read again*/
-	len = SDMMC_GET_FCNT(mci_readl(host, STATUS));
 	host->pio_offset = offset;
 	data->bytes_xfered += nbytes;
 	return;
@@ -1116,8 +1312,9 @@ static void dw_mci_write_data_pio(struct dw_mci *host)
 	unsigned int nbytes = 0, len;
 
 	do {
-		len = (host->fifo_depth -
-			SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift;
+		len = ((host->fifo_depth -
+			SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift)
+			- host->part_buf_count;
 		if (offset + len <= sg->length) {
 			host->push_data(host, (void *)(buf + offset), len);
 
@@ -1162,10 +1359,8 @@ static void dw_mci_write_data_pio(struct dw_mci *host)
 			return;
 		}
 	} while (status & SDMMC_INT_TXDR); /* if TXDR write again */
-
 	host->pio_offset = offset;
 	data->bytes_xfered += nbytes;
-
 	return;
 
 done:
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index 01db1a0..f3f68ee 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -76,6 +76,9 @@ struct mmc_data;
  * @slot: Slots sharing this MMC controller.
  * @fifo_depth: depth of FIFO.
  * @data_shift: log2 of FIFO item size.
+ * @part_buf_start: Start index in part_buf.
+ * @part_buf_count: Bytes of partial data in part_buf.
+ * @part_buf: Simple buffer for partial fifo reads/writes.
  * @push_data: Pointer to FIFO push function.
  * @pull_data: Pointer to FIFO pull function.
  * @quirks: Set of quirks that apply to specific versions of the IP.
@@ -149,6 +152,13 @@ struct dw_mci {
 	/* FIFO push and pull */
 	int			fifo_depth;
 	int			data_shift;
+	u8			part_buf_start;
+	u8			part_buf_count;
+	union {
+		u16		part_buf16;
+		u32		part_buf32;
+		u64		part_buf;
+	};
 	void (*push_data)(struct dw_mci *host, void *buf, int cnt);
 	void (*pull_data)(struct dw_mci *host, void *buf, int cnt);
 
-- 
1.7.2.3

Re: [PATCH 0/6] mmc: dw_mmc: misc fixes and improvements

[Will Newton]

On Fri, Jun 24, 2011 at 1:52 PM, James Hogan <james.hogan@imgtec.com> wrote:
> Misc improvements and fixes for the Synopsys DesignWare MMC driver:
>
> [PATCH 1/6] mmc: dw_mmc: clear TXDR/RXDR ints before enabling
>        fixes a failure to probe the next card after an unplug
> [PATCH 2/6] mmc: dw_mmc: fix race with request and removal
>        improves spinlock protection
> [PATCH 3/6] mmc: dw_mmc: convert card tasklet to workqueue
>        to allow platform callbacks to sleep
> [PATCH 4/6] mmc: dw_mmc: brackets in register access macros
>        just a small tidyup patch
> [PATCH 5/6] mmc: dw_mmc: don't hard code fifo depth, fix usage
>        improve detection of fifo depth
> [PATCH 6/6] mmc: dw_mmc: handle unaligned buffers and sizes
>        fix some mmc_test failures wrt unaligned buffer/sizes
>
>  drivers/mmc/host/dw_mmc.c  |  398 ++++++++++++++++++++++++++++++++++----------
>  drivers/mmc/host/dw_mmc.h  |   17 +-
>  include/linux/mmc/dw_mmc.h |   20 ++-
>  3 files changed, 340 insertions(+), 95 deletions(-)

All these patches:

Acked-by: Will Newton <will.newton@imgtec.com>