diff mbox

[2/4] spi: s3c64xx: added support for polling mode

Message ID 1360105784-12282-3-git-send-email-ks.giri@samsung.com
State Superseded, archived
Headers show

Commit Message

girishks2000@gmail.com Feb. 5, 2013, 11:09 p.m. UTC
The 64xx spi driver supports partial polling mode.
Only the last chunk of the transfer length is transferred
or recieved in polling mode.

Some SoC's that adopt this controller might not have have dma
interface. This patch adds support for complete polling mode
and gives flexibity for the user to select poll/dma mode.

Signed-off-by: Girish K S <ks.giri@samsung.com>
---
 drivers/spi/spi-s3c64xx.c |   65 +++++++++++++++++++++------------------------
 1 file changed, 30 insertions(+), 35 deletions(-)

Comments

Grant Likely Feb. 6, 2013, 10:35 a.m. UTC | #1
On Tue,  5 Feb 2013 15:09:42 -0800, Girish K S <girishks2000@gmail.com> wrote:
> The 64xx spi driver supports partial polling mode.
> Only the last chunk of the transfer length is transferred
> or recieved in polling mode.
> 
> Some SoC's that adopt this controller might not have have dma
> interface. This patch adds support for complete polling mode
> and gives flexibity for the user to select poll/dma mode.
> 
> Signed-off-by: Girish K S <ks.giri@samsung.com>
> ---
>  drivers/spi/spi-s3c64xx.c |   65 +++++++++++++++++++++------------------------
>  1 file changed, 30 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index b770f88..90770bd 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -345,19 +348,7 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
>  
>  	chcfg = readl(regs + S3C64XX_SPI_CH_CFG);
>  	chcfg &= ~S3C64XX_SPI_CH_TXCH_ON;
> -
> -	if (dma_mode) {
>  		chcfg &= ~S3C64XX_SPI_CH_RXCH_ON;
> -	} else {
> -		/* Always shift in data in FIFO, even if xfer is Tx only,
> -		 * this helps setting PCKT_CNT value for generating clocks
> -		 * as exactly needed.
> -		 */
> -		chcfg |= S3C64XX_SPI_CH_RXCH_ON;
> -		writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
> -					| S3C64XX_SPI_PACKET_CNT_EN,
> -					regs + S3C64XX_SPI_PACKET_CNT);
> -	}

The removes a block of code, but leaves the modification of chcfg where
it is without fixing the indentation. I could also use some help
understanding why this particular else block is moved down in the
function.

>  	if (xfer->tx_buf != NULL) {
>  		sdd->state |= TXBUSY;
> @@ -385,6 +376,10 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
>  
>  	if (xfer->rx_buf != NULL) {
>  		sdd->state |= RXBUSY;
> +		chcfg |= S3C64XX_SPI_CH_RXCH_ON;
> +		writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
> +				| S3C64XX_SPI_PACKET_CNT_EN,
> +				regs + S3C64XX_SPI_PACKET_CNT);
>  
>  		if (sdd->port_conf->high_speed && sdd->cur_speed >= 30000000UL
>  					&& !(sdd->cur_mode & SPI_CPHA))
> @@ -392,10 +387,6 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
>  
>  		if (dma_mode) {
>  			modecfg |= S3C64XX_SPI_MODE_RXDMA_ON;
> -			chcfg |= S3C64XX_SPI_CH_RXCH_ON;
> -			writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
> -					| S3C64XX_SPI_PACKET_CNT_EN,
> -					regs + S3C64XX_SPI_PACKET_CNT);
>  			prepare_dma(&sdd->rx_dma, xfer->len, xfer->rx_dma);
>  		}
>  	}
> @@ -421,6 +412,9 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
>  
>  	cs = spi->controller_data;
>  	gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
> +
> +	/* Start the signals */
> +	writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
>  }
>  
>  static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
> @@ -480,16 +474,19 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
>  
>  		switch (sdd->cur_bpw) {
>  		case 32:
> -			ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
> -				xfer->rx_buf, xfer->len / 4);
> +			for (val = 0; val < (xfer->len / 4); val++)
> +				*((u32 *)xfer->rx_buf + val) =
> +					ioread32(regs + S3C64XX_SPI_RX_DATA);
>  			break;
>  		case 16:
> -			ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
> -				xfer->rx_buf, xfer->len / 2);
> +			for (val = 0; val < (xfer->len / 2); val++)
> +				*((u16 *)xfer->rx_buf + val) =
> +					ioread16(regs + S3C64XX_SPI_RX_DATA);
>  			break;
>  		default:
> -			ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
> -				xfer->rx_buf, xfer->len);
> +			for (val = 0; val < xfer->len; val++)
> +				*((u8 *)xfer->rx_buf + val) =
> +					ioread8(regs + S3C64XX_SPI_RX_DATA);

What are all of the above lines changed? That seems to have nothing to
do with making the driver be albe to do polling transfers. Nor is it
described in the patch description.

I think this patch needs some more work. It certainly need to be
described better, and it appears that some of the changes really should be
in a separate patch.

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girishks2000@gmail.com Feb. 6, 2013, 10:04 p.m. UTC | #2
On Wed, Feb 6, 2013 at 2:35 AM, Grant Likely <grant.likely@secretlab.ca> wrote:
> On Tue,  5 Feb 2013 15:09:42 -0800, Girish K S <girishks2000@gmail.com> wrote:
>> The 64xx spi driver supports partial polling mode.
>> Only the last chunk of the transfer length is transferred
>> or recieved in polling mode.
>>
>> Some SoC's that adopt this controller might not have have dma
>> interface. This patch adds support for complete polling mode
>> and gives flexibity for the user to select poll/dma mode.
>>
>> Signed-off-by: Girish K S <ks.giri@samsung.com>
>> ---
>>  drivers/spi/spi-s3c64xx.c |   65 +++++++++++++++++++++------------------------
>>  1 file changed, 30 insertions(+), 35 deletions(-)
>>
>> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
>> index b770f88..90770bd 100644
>> --- a/drivers/spi/spi-s3c64xx.c
>> +++ b/drivers/spi/spi-s3c64xx.c
>> @@ -345,19 +348,7 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
>>
>>       chcfg = readl(regs + S3C64XX_SPI_CH_CFG);
>>       chcfg &= ~S3C64XX_SPI_CH_TXCH_ON;
>> -
>> -     if (dma_mode) {
>>               chcfg &= ~S3C64XX_SPI_CH_RXCH_ON;
>> -     } else {
>> -             /* Always shift in data in FIFO, even if xfer is Tx only,
>> -              * this helps setting PCKT_CNT value for generating clocks
>> -              * as exactly needed.
>> -              */
>> -             chcfg |= S3C64XX_SPI_CH_RXCH_ON;
>> -             writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
>> -                                     | S3C64XX_SPI_PACKET_CNT_EN,
>> -                                     regs + S3C64XX_SPI_PACKET_CNT);
>> -     }
>
> The removes a block of code, but leaves the modification of chcfg where
> it is without fixing the indentation. I could also use some help
Yes sorry missed that indentation.
> understanding why this particular else block is moved down in the
> function.
The else block is related only to polling mode, so moved it inside the
rx block.
Clock generation and RX is enabled only when there is a valid Rx
buffer to receive the data from FIFO.

>
>>       if (xfer->tx_buf != NULL) {
>>               sdd->state |= TXBUSY;
>> @@ -385,6 +376,10 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
>>
>>       if (xfer->rx_buf != NULL) {
>>               sdd->state |= RXBUSY;
>> +             chcfg |= S3C64XX_SPI_CH_RXCH_ON;
>> +             writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
>> +                             | S3C64XX_SPI_PACKET_CNT_EN,
>> +                             regs + S3C64XX_SPI_PACKET_CNT);
>>
>>               if (sdd->port_conf->high_speed && sdd->cur_speed >= 30000000UL
>>                                       && !(sdd->cur_mode & SPI_CPHA))
>> @@ -392,10 +387,6 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
>>
>>               if (dma_mode) {
>>                       modecfg |= S3C64XX_SPI_MODE_RXDMA_ON;
>> -                     chcfg |= S3C64XX_SPI_CH_RXCH_ON;
>> -                     writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
>> -                                     | S3C64XX_SPI_PACKET_CNT_EN,
>> -                                     regs + S3C64XX_SPI_PACKET_CNT);
>>                       prepare_dma(&sdd->rx_dma, xfer->len, xfer->rx_dma);
>>               }
>>       }
>> @@ -421,6 +412,9 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
>>
>>       cs = spi->controller_data;
>>       gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
>> +
>> +     /* Start the signals */
>> +     writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
>>  }
>>
>>  static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
>> @@ -480,16 +474,19 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
>>
>>               switch (sdd->cur_bpw) {
>>               case 32:
>> -                     ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
>> -                             xfer->rx_buf, xfer->len / 4);
>> +                     for (val = 0; val < (xfer->len / 4); val++)
>> +                             *((u32 *)xfer->rx_buf + val) =
>> +                                     ioread32(regs + S3C64XX_SPI_RX_DATA);
>>                       break;
>>               case 16:
>> -                     ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
>> -                             xfer->rx_buf, xfer->len / 2);
>> +                     for (val = 0; val < (xfer->len / 2); val++)
>> +                             *((u16 *)xfer->rx_buf + val) =
>> +                                     ioread16(regs + S3C64XX_SPI_RX_DATA);
>>                       break;
>>               default:
>> -                     ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
>> -                             xfer->rx_buf, xfer->len);
>> +                     for (val = 0; val < xfer->len; val++)
>> +                             *((u8 *)xfer->rx_buf + val) =
>> +                                     ioread8(regs + S3C64XX_SPI_RX_DATA);
>
> What are all of the above lines changed? That seems to have nothing to
> do with making the driver be albe to do polling transfers. Nor is it
> described in the patch description.
As per the original implementation, the polling path is taken only for
the last chunk of tarnsfer size. The last chunk is always
<=  all other other previous transfers. so readx_rep can read the FIFO
data successfully for the given transfer size.
But in polling mode, readx_rep would read junk if the transfer size is
more than the threshold limit.
e.g
dd if=/dev/mtd0  of=temp.bin bs=512 count=1
In this case transfer size to receive is 512. The threshold for FIFO
is 128 bytes (half of FIFO depth, i didnt modify this as it is in DMA
transfer also)
Now in the above receive case with repx_read, i always received first
128 valid bytes and all the rest as junk. With the above modification
I just make sure i read out all the data whatever is received 1 by 1.
>
> I think this patch needs some more work. It certainly need to be
> described better, and it appears that some of the changes really should be
> in a separate patch.
sure I will give a clear description of what is done.

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diff mbox

Patch

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index b770f88..90770bd 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -35,6 +35,7 @@ 
 #include <linux/platform_data/spi-s3c64xx.h>
 
 #define MAX_SPI_PORTS		3
+#define S3C64XX_SPI_QUIRK_POLL		(1 << 0)
 
 /* Registers and bit-fields */
 
@@ -126,6 +127,7 @@ 
 #define S3C64XX_SPI_TRAILCNT		S3C64XX_SPI_MAX_TRAILCNT
 
 #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
+#define is_polling(x)	(x->port_conf->quirks & S3C64XX_SPI_QUIRK_POLL)
 
 #define RXBUSY    (1<<2)
 #define TXBUSY    (1<<3)
@@ -155,6 +157,7 @@  struct s3c64xx_spi_port_config {
 	int	fifo_lvl_mask[MAX_SPI_PORTS];
 	int	rx_lvl_offset;
 	int	tx_st_done;
+	int	quirks;
 	bool	high_speed;
 	bool	clk_from_cmu;
 };
@@ -345,19 +348,7 @@  static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
 
 	chcfg = readl(regs + S3C64XX_SPI_CH_CFG);
 	chcfg &= ~S3C64XX_SPI_CH_TXCH_ON;
-
-	if (dma_mode) {
 		chcfg &= ~S3C64XX_SPI_CH_RXCH_ON;
-	} else {
-		/* Always shift in data in FIFO, even if xfer is Tx only,
-		 * this helps setting PCKT_CNT value for generating clocks
-		 * as exactly needed.
-		 */
-		chcfg |= S3C64XX_SPI_CH_RXCH_ON;
-		writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
-					| S3C64XX_SPI_PACKET_CNT_EN,
-					regs + S3C64XX_SPI_PACKET_CNT);
-	}
 
 	if (xfer->tx_buf != NULL) {
 		sdd->state |= TXBUSY;
@@ -385,6 +376,10 @@  static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
 
 	if (xfer->rx_buf != NULL) {
 		sdd->state |= RXBUSY;
+		chcfg |= S3C64XX_SPI_CH_RXCH_ON;
+		writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
+				| S3C64XX_SPI_PACKET_CNT_EN,
+				regs + S3C64XX_SPI_PACKET_CNT);
 
 		if (sdd->port_conf->high_speed && sdd->cur_speed >= 30000000UL
 					&& !(sdd->cur_mode & SPI_CPHA))
@@ -392,10 +387,6 @@  static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
 
 		if (dma_mode) {
 			modecfg |= S3C64XX_SPI_MODE_RXDMA_ON;
-			chcfg |= S3C64XX_SPI_CH_RXCH_ON;
-			writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
-					| S3C64XX_SPI_PACKET_CNT_EN,
-					regs + S3C64XX_SPI_PACKET_CNT);
 			prepare_dma(&sdd->rx_dma, xfer->len, xfer->rx_dma);
 		}
 	}
@@ -421,6 +412,9 @@  static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
 
 	cs = spi->controller_data;
 	gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
+
+	/* Start the signals */
+	writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
 }
 
 static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
@@ -445,12 +439,12 @@  static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
 		} while (RX_FIFO_LVL(status, sdd) < xfer->len && --val);
 	}
 
-	if (!val)
-		return -EIO;
-
 	if (dma_mode) {
 		u32 status;
 
+		if (!val)
+			return -EIO;
+
 		/*
 		 * DmaTx returns after simply writing data in the FIFO,
 		 * w/o waiting for real transmission on the bus to finish.
@@ -480,16 +474,19 @@  static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
 
 		switch (sdd->cur_bpw) {
 		case 32:
-			ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
-				xfer->rx_buf, xfer->len / 4);
+			for (val = 0; val < (xfer->len / 4); val++)
+				*((u32 *)xfer->rx_buf + val) =
+					ioread32(regs + S3C64XX_SPI_RX_DATA);
 			break;
 		case 16:
-			ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
-				xfer->rx_buf, xfer->len / 2);
+			for (val = 0; val < (xfer->len / 2); val++)
+				*((u16 *)xfer->rx_buf + val) =
+					ioread16(regs + S3C64XX_SPI_RX_DATA);
 			break;
 		default:
-			ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
-				xfer->rx_buf, xfer->len);
+			for (val = 0; val < xfer->len; val++)
+				*((u8 *)xfer->rx_buf + val) =
+					ioread8(regs + S3C64XX_SPI_RX_DATA);
 			break;
 		}
 		sdd->state &= ~RXBUSY;
@@ -507,6 +504,10 @@  static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd,
 		sdd->tgl_spi = NULL;
 
 	gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1);
+
+	/* Quiese the signals */
+	writel(S3C64XX_SPI_SLAVE_SIG_INACT,
+	sdd->regs + S3C64XX_SPI_SLAVE_SEL);
 }
 
 static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
@@ -588,7 +589,7 @@  static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
 	struct device *dev = &sdd->pdev->dev;
 	struct spi_transfer *xfer;
 
-	if (msg->is_dma_mapped)
+	if (is_polling(sdd) || msg->is_dma_mapped)
 		return 0;
 
 	/* First mark all xfer unmapped */
@@ -637,7 +638,7 @@  static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd,
 	struct device *dev = &sdd->pdev->dev;
 	struct spi_transfer *xfer;
 
-	if (msg->is_dma_mapped)
+	if (is_polling(sdd) || msg->is_dma_mapped)
 		return;
 
 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
@@ -715,7 +716,8 @@  static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
 		}
 
 		/* Polling method for xfers not bigger than FIFO capacity */
-		if (xfer->len <= ((FIFO_LVL_MASK(sdd) >> 1) + 1))
+		if (is_polling(sdd) ||
+			xfer->len <= ((FIFO_LVL_MASK(sdd) >> 1) + 1))
 			use_dma = 0;
 		else
 			use_dma = 1;
@@ -731,17 +733,10 @@  static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
 		/* Slave Select */
 		enable_cs(sdd, spi);
 
-		/* Start the signals */
-		writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
-
 		spin_unlock_irqrestore(&sdd->lock, flags);
 
 		status = wait_for_xfer(sdd, xfer, use_dma);
 
-		/* Quiese the signals */
-		writel(S3C64XX_SPI_SLAVE_SIG_INACT,
-		       sdd->regs + S3C64XX_SPI_SLAVE_SEL);
-
 		if (status) {
 			dev_err(&spi->dev, "I/O Error: "
 				"rx-%d tx-%d res:rx-%c tx-%c len-%d\n",