[PATCH v2 1/3] spi: spi-fsl-dspi: Enable TCF interrupt mode support

[PATCH v2 1/3] spi: spi-fsl-dspi: Enable TCF interrupt mode support

[Haikun Wang]

DSPI module has two optional interrupts when complete data transfer.
One is EOQ interrupt, the other one is TCF interrupt.
EOQ indicates a queue of data frame has been transmitted.
TCF indicates a frame has been transmitted.
This patch enable support TCF mode.
User can configure expected mode in dts node.

Signed-off-by: Haikun Wang <haikun.wang-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
---

Changes in v2:
- Remove global variable g_actual_length
- Add "dspi->dataflags &= ~TRAN_STATE_WORD_ODD_NUM" 
  if dataflags has TRAN_STATE_WORD_ODD_NUM in IRQ handler
- Move single byte chacking inside while loop in function dspi_eoq_write 

Changes in v1: None
 drivers/spi/spi-fsl-dspi.c | 191 +++++++++++++++++++++++++++------------------
 1 file changed, 117 insertions(+), 74 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 5fe54cd..75c5796 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -67,9 +67,11 @@
 
 #define SPI_SR			0x2c
 #define SPI_SR_EOQF		0x10000000
+#define SPI_SR_TCFQF		0x80000000
 
 #define SPI_RSER		0x30
 #define SPI_RSER_EOQFE		0x10000000
+#define SPI_RSER_TCFQE		0x80000000
 
 #define SPI_PUSHR		0x34
 #define SPI_PUSHR_CONT		(1 << 31)
@@ -108,6 +110,11 @@ struct chip_data {
 	u16 void_write_data;
 };
 
+enum dspi_trans_mode {
+	DSPI_EOQ_MODE = 0,
+	DSPI_TCFQ_MODE,
+};
+
 struct fsl_dspi {
 	struct spi_master	*master;
 	struct platform_device	*pdev;
@@ -128,6 +135,7 @@ struct fsl_dspi {
 	u8			cs;
 	u16			void_write_data;
 	u32			cs_change;
+	enum dspi_trans_mode	trans_mode;
 
 	wait_queue_head_t	waitq;
 	u32			waitflags;
@@ -213,63 +221,61 @@ static void ns_delay_scale(char *psc, char *sc, int delay_ns,
 	}
 }
 
-static int dspi_transfer_write(struct fsl_dspi *dspi)
+static u32 dspi_data_to_pushr(struct fsl_dspi *dspi, int tx_word)
 {
-	int tx_count = 0;
-	int tx_word;
 	u16 d16;
-	u8  d8;
-	u32 dspi_pushr = 0;
-	int first = 1;
 
-	tx_word = is_double_byte_mode(dspi);
+	if (!(dspi->dataflags & TRAN_STATE_TX_VOID))
+		d16 = tx_word ? *(u16 *)dspi->tx : *(u8 *)dspi->tx;
+	else
+		d16 = dspi->void_write_data;
 
-	/* If we are in word mode, but only have a single byte to transfer
-	 * then switch to byte mode temporarily.  Will switch back at the
-	 * end of the transfer.
-	 */
-	if (tx_word && (dspi->len == 1)) {
-		dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
-		regmap_update_bits(dspi->regmap, SPI_CTAR(dspi->cs),
-				SPI_FRAME_BITS_MASK, SPI_FRAME_BITS(8));
-		tx_word = 0;
-	}
+	dspi->tx += tx_word + 1;
+	dspi->len -= tx_word + 1;
 
-	while (dspi->len && (tx_count < DSPI_FIFO_SIZE)) {
-		if (tx_word) {
-			if (dspi->len == 1)
-				break;
+	return	SPI_PUSHR_TXDATA(d16) |
+		SPI_PUSHR_PCS(dspi->cs) |
+		SPI_PUSHR_CTAS(dspi->cs) |
+		SPI_PUSHR_CONT;
+}
 
-			if (!(dspi->dataflags & TRAN_STATE_TX_VOID)) {
-				d16 = *(u16 *)dspi->tx;
-				dspi->tx += 2;
-			} else {
-				d16 = dspi->void_write_data;
-			}
+static void dspi_data_from_popr(struct fsl_dspi *dspi, int rx_word)
+{
+	u16 d;
+	unsigned int val;
 
-			dspi_pushr = SPI_PUSHR_TXDATA(d16) |
-				SPI_PUSHR_PCS(dspi->cs) |
-				SPI_PUSHR_CTAS(dspi->cs) |
-				SPI_PUSHR_CONT;
+	regmap_read(dspi->regmap, SPI_POPR, &val);
+	d = SPI_POPR_RXDATA(val);
 
-			dspi->len -= 2;
-		} else {
-			if (!(dspi->dataflags & TRAN_STATE_TX_VOID)) {
+	if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
+		rx_word ? (*(u16 *)dspi->rx = d) : (*(u8 *)dspi->rx = d);
 
-				d8 = *(u8 *)dspi->tx;
-				dspi->tx++;
-			} else {
-				d8 = (u8)dspi->void_write_data;
-			}
+	dspi->rx += rx_word + 1;
+}
 
-			dspi_pushr = SPI_PUSHR_TXDATA(d8) |
-				SPI_PUSHR_PCS(dspi->cs) |
-				SPI_PUSHR_CTAS(dspi->cs) |
-				SPI_PUSHR_CONT;
+static int dspi_eoq_write(struct fsl_dspi *dspi)
+{
+	int tx_count = 0;
+	int tx_word;
+	u32 dspi_pushr = 0;
+	int first = 1;
+
+	tx_word = is_double_byte_mode(dspi);
 
-			dspi->len--;
+	while (dspi->len && (tx_count < DSPI_FIFO_SIZE)) {
+		/* If we are in word mode, only have a single byte to transfer
+		 * switch to byte mode temporarily.  Will switch back at the
+		 * end of the transfer.
+		 */
+		if (tx_word && (dspi->len == 1)) {
+			dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
+			regmap_update_bits(dspi->regmap, SPI_CTAR(dspi->cs),
+					SPI_FRAME_BITS_MASK, SPI_FRAME_BITS(8));
+			tx_word = 0;
 		}
 
+		dspi_pushr = dspi_data_to_pushr(dspi, tx_word);
+
 		if (dspi->len == 0 || tx_count == DSPI_FIFO_SIZE - 1) {
 			/* last transfer in the transfer */
 			dspi_pushr |= SPI_PUSHR_EOQ;
@@ -291,40 +297,55 @@ static int dspi_transfer_write(struct fsl_dspi *dspi)
 	return tx_count * (tx_word + 1);
 }
 
-static int dspi_transfer_read(struct fsl_dspi *dspi)
+static int dspi_eoq_read(struct fsl_dspi *dspi)
 {
 	int rx_count = 0;
 	int rx_word = is_double_byte_mode(dspi);
-	u16 d;
 
 	while ((dspi->rx < dspi->rx_end)
 			&& (rx_count < DSPI_FIFO_SIZE)) {
-		if (rx_word) {
-			unsigned int val;
+		if (rx_word && (dspi->rx_end - dspi->rx) == 1)
+			rx_word = 0;
 
-			if ((dspi->rx_end - dspi->rx) == 1)
-				break;
+		dspi_data_from_popr(dspi, rx_word);
+		rx_count++;
+	}
 
-			regmap_read(dspi->regmap, SPI_POPR, &val);
-			d = SPI_POPR_RXDATA(val);
+	return rx_count;
+}
 
-			if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
-				*(u16 *)dspi->rx = d;
-			dspi->rx += 2;
+static int dspi_tcfq_write(struct fsl_dspi *dspi)
+{
+	int tx_word;
+	u32 dspi_pushr = 0;
 
-		} else {
-			unsigned int val;
+	tx_word = is_double_byte_mode(dspi);
 
-			regmap_read(dspi->regmap, SPI_POPR, &val);
-			d = SPI_POPR_RXDATA(val);
-			if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
-				*(u8 *)dspi->rx = d;
-			dspi->rx++;
-		}
-		rx_count++;
+	if (tx_word && (dspi->len == 1)) {
+		dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
+		regmap_update_bits(dspi->regmap, SPI_CTAR(dspi->cs),
+				SPI_FRAME_BITS_MASK, SPI_FRAME_BITS(8));
+		tx_word = 0;
 	}
 
-	return rx_count;
+	dspi_pushr = dspi_data_to_pushr(dspi, tx_word);
+
+	if ((dspi->cs_change) && (!dspi->len))
+		dspi_pushr &= ~SPI_PUSHR_CONT;
+
+	regmap_write(dspi->regmap, SPI_PUSHR, dspi_pushr);
+
+	return tx_word + 1;
+}
+
+static void dspi_tcfq_read(struct fsl_dspi *dspi)
+{
+	int rx_word = is_double_byte_mode(dspi);
+
+	if (rx_word && (dspi->rx_end - dspi->rx) == 1)
+		rx_word = 0;
+
+	dspi_data_from_popr(dspi, rx_word);
 }
 
 static int dspi_transfer_one_message(struct spi_master *master,
@@ -334,6 +355,7 @@ static int dspi_transfer_one_message(struct spi_master *master,
 	struct spi_device *spi = message->spi;
 	struct spi_transfer *transfer;
 	int status = 0;
+
 	message->actual_length = 0;
 
 	list_for_each_entry(transfer, &message->transfers, transfer_list) {
@@ -370,8 +392,13 @@ static int dspi_transfer_one_message(struct spi_master *master,
 			regmap_write(dspi->regmap, SPI_CTAR(dspi->cs),
 					dspi->cur_chip->ctar_val);
 
-		regmap_write(dspi->regmap, SPI_RSER, SPI_RSER_EOQFE);
-		message->actual_length += dspi_transfer_write(dspi);
+		if (dspi->trans_mode == DSPI_EOQ_MODE) {
+			regmap_write(dspi->regmap, SPI_RSER, SPI_RSER_EOQFE);
+			message->actual_length += dspi_eoq_write(dspi);
+		} else if (dspi->trans_mode == DSPI_TCFQ_MODE) {
+			regmap_write(dspi->regmap, SPI_RSER, SPI_RSER_TCFQE);
+			message->actual_length += dspi_tcfq_write(dspi);
+		}
 
 		if (wait_event_interruptible(dspi->waitq, dspi->waitflags))
 			dev_err(&dspi->pdev->dev, "wait transfer complete fail!\n");
@@ -460,22 +487,31 @@ static void dspi_cleanup(struct spi_device *spi)
 static irqreturn_t dspi_interrupt(int irq, void *dev_id)
 {
 	struct fsl_dspi *dspi = (struct fsl_dspi *)dev_id;
-
 	struct spi_message *msg = dspi->cur_msg;
 
-	regmap_write(dspi->regmap, SPI_SR, SPI_SR_EOQF);
-	dspi_transfer_read(dspi);
+	if (dspi->trans_mode == DSPI_EOQ_MODE) {
+		regmap_write(dspi->regmap, SPI_SR, SPI_SR_EOQF);
+		dspi_eoq_read(dspi);
+	} else if (dspi->trans_mode == DSPI_TCFQ_MODE) {
+		regmap_write(dspi->regmap, SPI_SR, SPI_SR_TCFQF);
+		dspi_tcfq_read(dspi);
+	}
 
 	if (!dspi->len) {
-		if (dspi->dataflags & TRAN_STATE_WORD_ODD_NUM)
+		if (dspi->dataflags & TRAN_STATE_WORD_ODD_NUM) {
 			regmap_update_bits(dspi->regmap, SPI_CTAR(dspi->cs),
 			SPI_FRAME_BITS_MASK, SPI_FRAME_BITS(16));
+			dspi->dataflags &= ~TRAN_STATE_WORD_ODD_NUM;
+		}
 
 		dspi->waitflags = 1;
 		wake_up_interruptible(&dspi->waitq);
-	} else
-		msg->actual_length += dspi_transfer_write(dspi);
-
+	} else {
+		if (dspi->trans_mode == DSPI_EOQ_MODE)
+			msg->actual_length += dspi_eoq_write(dspi);
+		else if (dspi->trans_mode == DSPI_TCFQ_MODE)
+			msg->actual_length += dspi_tcfq_write(dspi);
+	}
 	return IRQ_HANDLED;
 }
 
@@ -559,6 +595,13 @@ static int dspi_probe(struct platform_device *pdev)
 	}
 	master->bus_num = bus_num;
 
+	if (of_property_read_bool(np, "eoq-mode"))
+		dspi->trans_mode = DSPI_EOQ_MODE;
+	else if (of_property_read_bool(np, "tcfq-mode"))
+		dspi->trans_mode = DSPI_TCFQ_MODE;
+	else
+		dspi->trans_mode = DSPI_TCFQ_MODE;
+
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(base)) {
-- 
2.1.0.27.g96db324

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Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Enable TCF interrupt mode support

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 437 bytes --]

On Wed, May 13, 2015 at 06:11:51PM +0800, Haikun Wang wrote:
> DSPI module has two optional interrupts when complete data transfer.
> One is EOQ interrupt, the other one is TCF interrupt.
> EOQ indicates a queue of data frame has been transmitted.
> TCF indicates a frame has been transmitted.
> This patch enable support TCF mode.
> User can configure expected mode in dts node.

Same feedback as before: why make this user selectable?

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Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Enable TCF interrupt mode support

[Wang Haikun]

On 5/14/2015 2:17 AM, Mark Brown wrote:
> On Wed, May 13, 2015 at 06:11:51PM +0800, Haikun Wang wrote:
>> DSPI module has two optional interrupts when complete data transfer.
>> One is EOQ interrupt, the other one is TCF interrupt.
>> EOQ indicates a queue of data frame has been transmitted.
>> TCF indicates a frame has been transmitted.
>> This patch enable support TCF mode.
>> User can configure expected mode in dts node.
>
> Same feedback as before: why make this user selectable?
"This is adding a DT binding without documenting it, all DT bindings need
to be documented.  I'm also not clear why this is something the user
would want to be able to select from DT - what is platform specific
about this?  Shouldn't the driver just ensure that the most appropriate
interrupt mode is used?"

Yes, you are right. Platforms are different about this. Some platform 
only can work in one of the interrupt mode due to silicon issue. So we 
need support both of the two modes and chose the correct one in the dts 
node.

I will send a patch updating the doc.
>


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Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Enable TCF interrupt mode support

[Mark Brown]

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On Thu, May 14, 2015 at 02:26:53AM +0000, Wang Haikun wrote:

> Yes, you are right. Platforms are different about this. Some platform 
> only can work in one of the interrupt mode due to silicon issue. So we 
> need support both of the two modes and chose the correct one in the dts 
> node.

It is more normal to do this sort of selection by having different
compatible strings for the different versions of the IP (often using the
SoC name if the IP isn't versioned) - that way we don't need individual
properties for every difference in the silicon and we only need to
update the kernel and not the device tree if we discover some issue.

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Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Enable TCF interrupt mode support

[Wang Haikun]

On 5/14/2015 5:56 PM, Mark Brown wrote:
> On Thu, May 14, 2015 at 02:26:53AM +0000, Wang Haikun wrote:
>
>> Yes, you are right. Platforms are different about this. Some platform
>> only can work in one of the interrupt mode due to silicon issue. So we
>> need support both of the two modes and chose the correct one in the dts
>> node.
>
> It is more normal to do this sort of selection by having different
> compatible strings for the different versions of the IP (often using the
> SoC name if the IP isn't versioned) - that way we don't need individual
> properties for every difference in the silicon and we only need to
> update the kernel and not the device tree if we discover some issue.
>
Fine, I will adopt your advice.
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