[COMMON] spi: s3c64xx: divide tranfer length in DMA mode.

When transfer length is over the max value of COUNT_VALUE in PACKET_CNT_REG,
spi H/W only perceives the bits of COUNT_VALUE, so spiclk is
generated less than expected numbers.
Therefore, transfer length must be divided under the max value of
PACKET_CNT COUNT_VALUE.

Change-Id: Ic3faa2dda2076544176f97d32507da63f46e24a3
Signed-off-by: myung-su.cha <myung-su.cha@samsung.com>

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index e400d1c89b25a485fdbfcd0eb099bdc96e54bae6..bf17f8e31c7a97466ec723f7a2bf74056802c598 100644 (file)
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -158,6 +158,9 @@ static LIST_HEAD(drvdata_list);
 #define USI_HWACG_CLKREQ_ON            (1<<1)
 #define USI_HWACG_CLKSTOP_ON           (1<<2)
 
+/* MAX SIZE of COUNT_VALUE in PACKET_CNT_REG */
+#define S3C64XX_SPI_PACKET_CNT_MAX 0xffff
+
 /**
  * struct s3c64xx_spi_info - SPI Controller hardware info
  * @fifo_lvl_mask: Bit-mask for {TX|RX}_FIFO_LVL bits in SPI_STATUS register.
@@ -839,83 +842,77 @@ static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
 
 #define XFER_DMAADDR_INVALID DMA_BIT_MASK(36)
 
-static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
+static int s3c64xx_spi_dma_initialize(struct s3c64xx_spi_driver_data *sdd,
                                                struct spi_message *msg)
 {
-       struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
-       struct device *dev = &sdd->pdev->dev;
        struct spi_transfer *xfer;
 
-       if ((msg->is_dma_mapped) || (sci->dma_mode != DMA_MODE))
-               return 0;
-
        /* First mark all xfer unmapped */
        list_for_each_entry(xfer, &msg->transfers, transfer_list) {
                xfer->rx_dma = XFER_DMAADDR_INVALID;
                xfer->tx_dma = XFER_DMAADDR_INVALID;
        }
 
-       /* Map until end or first fail */
-       list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+       return 0;
+}
 
-               if (xfer->len <= ((FIFO_LVL_MASK(sdd) >> 1) + 1))
-                       continue;
+static int s3c64xx_spi_map_one_msg(struct s3c64xx_spi_driver_data *sdd,
+                                               struct spi_message *msg, struct spi_transfer *xfer)
+{
+       struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
+       struct device *dev = &sdd->pdev->dev;
 
-               if (xfer->tx_buf != NULL) {
-                       xfer->tx_dma = dma_map_single(dev,
-                                       (void *)xfer->tx_buf, xfer->len,
-                                       DMA_TO_DEVICE);
-                       if (dma_mapping_error(dev, xfer->tx_dma)) {
-                               dev_err(dev, "dma_map_single Tx failed\n");
-                               xfer->tx_dma = XFER_DMAADDR_INVALID;
-                               return -ENOMEM;
-                       }
+       if ((msg->is_dma_mapped) || (sci->dma_mode != DMA_MODE))
+               return 0;
+
+       if (xfer->tx_buf != NULL) {
+               xfer->tx_dma = dma_map_single(dev,
+                               (void *)xfer->tx_buf, xfer->len,
+                               DMA_TO_DEVICE);
+               if (dma_mapping_error(dev, xfer->tx_dma)) {
+                       dev_err(dev, "dma_map_single Tx failed\n");
+                       xfer->tx_dma = XFER_DMAADDR_INVALID;
+                       return -ENOMEM;
                }
+       }
 
-               if (xfer->rx_buf != NULL) {
-                       xfer->rx_dma = dma_map_single(dev, xfer->rx_buf,
-                                               xfer->len, DMA_FROM_DEVICE);
-                       if (dma_mapping_error(dev, xfer->rx_dma)) {
-                               dev_err(dev, "dma_map_single Rx failed\n");
-                               dma_unmap_single(dev, xfer->tx_dma,
-                                               xfer->len, DMA_TO_DEVICE);
-                               xfer->tx_dma = XFER_DMAADDR_INVALID;
-                               xfer->rx_dma = XFER_DMAADDR_INVALID;
-                               return -ENOMEM;
-                       }
+       if (xfer->rx_buf != NULL) {
+               xfer->rx_dma = dma_map_single(dev, xfer->rx_buf,
+                                       xfer->len, DMA_FROM_DEVICE);
+               if (dma_mapping_error(dev, xfer->rx_dma)) {
+                       dev_err(dev, "dma_map_single Rx failed\n");
+                       dma_unmap_single(dev, xfer->tx_dma,
+                                       xfer->len, DMA_TO_DEVICE);
+                       xfer->tx_dma = XFER_DMAADDR_INVALID;
+                       xfer->rx_dma = XFER_DMAADDR_INVALID;
+                       return -ENOMEM;
                }
        }
 
        return 0;
 }
 
-static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd,
-                                               struct spi_message *msg)
+static void s3c64xx_spi_unmap_one_msg(struct s3c64xx_spi_driver_data *sdd,
+                                               struct spi_message *msg, struct spi_transfer *xfer)
 {
        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
        struct device *dev = &sdd->pdev->dev;
-       struct spi_transfer *xfer;
 
        if ((msg->is_dma_mapped) || (sci->dma_mode != DMA_MODE))
                return;
 
-       list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+       if (xfer->rx_buf != NULL
+                       && xfer->rx_dma != XFER_DMAADDR_INVALID)
+               dma_unmap_single(dev, xfer->rx_dma,
+                                       xfer->len, DMA_FROM_DEVICE);
 
-               if (xfer->len <= ((FIFO_LVL_MASK(sdd) >> 1) + 1))
-                       continue;
-
-               if (xfer->rx_buf != NULL
-                               && xfer->rx_dma != XFER_DMAADDR_INVALID)
-                       dma_unmap_single(dev, xfer->rx_dma,
-                                               xfer->len, DMA_FROM_DEVICE);
-
-               if (xfer->tx_buf != NULL
-                               && xfer->tx_dma != XFER_DMAADDR_INVALID)
-                       dma_unmap_single(dev, xfer->tx_dma,
-                                               xfer->len, DMA_TO_DEVICE);
-       }
+       if (xfer->tx_buf != NULL
+                       && xfer->tx_dma != XFER_DMAADDR_INVALID)
+               dma_unmap_single(dev, xfer->tx_dma,
+                                       xfer->len, DMA_TO_DEVICE);
 }
 
+
 static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
                                            struct spi_message *msg)
 {
@@ -942,12 +939,8 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
                s3c64xx_spi_config(sdd);
        }
 
-       /* Map all the transfers if needed */
-       if (s3c64xx_spi_map_mssg(sdd, msg)) {
-               dev_err(&spi->dev,
-                       "Xfer: Unable to map message buffers!\n");
-               status = -ENOMEM;
-               goto out;
+       if (!(msg->is_dma_mapped) && (sci->dma_mode == DMA_MODE)){
+               s3c64xx_spi_dma_initialize(sdd, msg);
        }
 
        /* Configure feedback delay */
@@ -991,6 +984,27 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
                        if (xfer->len > fifo_lvl)
                                xfer->len = fifo_lvl;
                } else {
+
+                       /* backup original tx, rx buf ptr & xfer length */
+                       origin_tx_buf = xfer->tx_buf;
+                       origin_rx_buf = xfer->rx_buf;
+                       origin_len = xfer->len;
+
+                       target_len = xfer->len;
+                       if (xfer->len > S3C64XX_SPI_PACKET_CNT_MAX * sdd->cur_bpw / 8)
+                               xfer->len = S3C64XX_SPI_PACKET_CNT_MAX * sdd->cur_bpw / 8;
+               }
+try_transfer:
+               if (sci->dma_mode == DMA_MODE) {
+
+                       /* Map the transfer if needed */
+                       if (s3c64xx_spi_map_one_msg(sdd, msg, xfer)) {
+                               dev_err(&spi->dev,
+                                       "Xfer: Unable to map message buffers!\n");
+                               status = -ENOMEM;
+                               goto out;
+                       }
+
                /* Polling method for xfers not bigger than FIFO capacity */
                        if (xfer->len <= fifo_lvl) {
                                use_dma = 0;
@@ -998,7 +1012,7 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
                                use_dma = 1;
                        }
                }
-try_transfer:
+
                spin_lock_irqsave(&sdd->lock, flags);
 
                /* Pending only which is to be done */
@@ -1079,6 +1093,30 @@ try_transfer:
                                goto try_transfer;
                        }
 
+                       /* restore original tx, rx buf_ptr & xfer length */
+                       xfer->tx_buf = origin_tx_buf;
+                       xfer->rx_buf = origin_rx_buf;
+                       xfer->len = origin_len;
+               } else {
+
+                       s3c64xx_spi_unmap_one_msg(sdd, msg, xfer);
+
+                       target_len -= xfer->len;
+
+                       if (xfer->tx_buf != NULL)
+                               xfer->tx_buf += xfer->len;
+
+                       if (xfer->rx_buf != NULL)
+                               xfer->rx_buf += xfer->len;
+
+                       if (target_len > 0) {
+                               if (target_len > S3C64XX_SPI_PACKET_CNT_MAX * sdd->cur_bpw / 8)
+                                       xfer->len = S3C64XX_SPI_PACKET_CNT_MAX * sdd->cur_bpw / 8;
+                               else
+                                       xfer->len = target_len;
+                               goto try_transfer;
+                       }
+
                        /* restore original tx, rx buf_ptr & xfer length */
                        xfer->tx_buf = origin_tx_buf;
                        xfer->rx_buf = origin_rx_buf;
@@ -1092,8 +1130,6 @@ out:
        else
                sdd->tgl_spi = spi;
 
-       s3c64xx_spi_unmap_mssg(sdd, msg);
-
        msg->status = status;
 
        spi_finalize_current_message(master);