spi: rspi: Remove unused 16-bit DMA support

The 16-bit DMA support doesn't fit well within the SPI core DMA framework,
as it needs to manage its own double-sized temporary buffers, for handling
the interleaved data.
Remove it, as there is no in-tree board code that sets
rspi_plat_data.dma_width_16bit.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
(cherry picked from commit 9c5de2c1754c2bb3c69c4d7bf0d0edc0a61d8232)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 57beda2..3bd06fd 100644 (file)
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -201,7 +201,6 @@ struct rspi_data {
        struct dma_chan *chan_tx;
        struct dma_chan *chan_rx;
 
-       unsigned dma_width_16bit:1;
        unsigned dma_callbacked:1;
        unsigned byte_access:1;
 };
@@ -475,60 +474,17 @@ static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan,
        dma_unmap_sg(chan->device->dev, sg, 1, dir);
 }
 
-static void rspi_memory_to_8bit(void *buf, const void *data, unsigned len)
-{
-       u16 *dst = buf;
-       const u8 *src = data;
-
-       while (len) {
-               *dst++ = (u16)(*src++);
-               len--;
-       }
-}
-
-static void rspi_memory_from_8bit(void *buf, const void *data, unsigned len)
-{
-       u8 *dst = buf;
-       const u16 *src = data;
-
-       while (len) {
-               *dst++ = (u8)*src++;
-               len--;
-       }
-}
-
 static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
 {
        struct scatterlist sg;
-       const void *buf = NULL;
+       const void *buf = t->tx_buf;
        struct dma_async_tx_descriptor *desc;
-       unsigned int len;
+       unsigned int len = t->len;
        int ret = 0;
 
-       if (rspi->dma_width_16bit) {
-               void *tmp;
-               /*
-                * If DMAC bus width is 16-bit, the driver allocates a dummy
-                * buffer. And, the driver converts original data into the
-                * DMAC data as the following format:
-                *  original data: 1st byte, 2nd byte ...
-                *  DMAC data:     1st byte, dummy, 2nd byte, dummy ...
-                */
-               len = t->len * 2;
-               tmp = kmalloc(len, GFP_KERNEL);
-               if (!tmp)
-                       return -ENOMEM;
-               rspi_memory_to_8bit(tmp, t->tx_buf, t->len);
-               buf = tmp;
-       } else {
-               len = t->len;
-               buf = t->tx_buf;
-       }
+       if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE))
+               return -EFAULT;
 
-       if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE)) {
-               ret = -EFAULT;
-               goto end_nomap;
-       }
        desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
                                       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc) {
@@ -563,10 +519,6 @@ static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
 
 end:
        rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
-end_nomap:
-       if (rspi->dma_width_16bit)
-               kfree(buf);
-
        return ret;
 }
 
@@ -603,28 +555,11 @@ static void qspi_receive_init(const struct rspi_data *rspi)
 static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
 {
        struct scatterlist sg, sg_dummy;
-       void *dummy = NULL, *rx_buf = NULL;
+       void *dummy = NULL, *rx_buf = t->rx_buf;
        struct dma_async_tx_descriptor *desc, *desc_dummy;
-       unsigned int len;
+       unsigned int len = t->len;
        int ret = 0;
 
-       if (rspi->dma_width_16bit) {
-               /*
-                * If DMAC bus width is 16-bit, the driver allocates a dummy
-                * buffer. And, finally the driver converts the DMAC data into
-                * actual data as the following format:
-                *  DMAC data:   1st byte, dummy, 2nd byte, dummy ...
-                *  actual data: 1st byte, 2nd byte ...
-                */
-               len = t->len * 2;
-               rx_buf = kmalloc(len, GFP_KERNEL);
-               if (!rx_buf)
-                       return -ENOMEM;
-        } else {
-               len = t->len;
-               rx_buf = t->rx_buf;
-       }
-
        /* prepare dummy transfer to generate SPI clocks */
        dummy = kzalloc(len, GFP_KERNEL);
        if (!dummy) {
@@ -697,11 +632,6 @@ end:
 end_dummy_mapped:
        rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE);
 end_nomap:
-       if (rspi->dma_width_16bit) {
-               if (!ret)
-                       rspi_memory_from_8bit(t->rx_buf, rx_buf, t->len);
-               kfree(rx_buf);
-       }
        kfree(dummy);
 
        return ret;
@@ -1073,8 +1003,6 @@ static int rspi_request_dma(struct rspi_data *rspi,
        if (!res || !rspi_pd)
                return 0;       /* The driver assumes no error. */
 
-       rspi->dma_width_16bit = rspi_pd->dma_width_16bit;
-
        /* If the module receives data by DMAC, it also needs TX DMAC */
        if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) {
                dma_cap_zero(mask);

diff --git a/include/linux/spi/rspi.h b/include/linux/spi/rspi.h
index a25bd6f..e546b2c 100644 (file)
--- a/include/linux/spi/rspi.h
+++ b/include/linux/spi/rspi.h
@@ -25,8 +25,6 @@ struct rspi_plat_data {
        unsigned int dma_tx_id;
        unsigned int dma_rx_id;
 
-       unsigned dma_width_16bit:1;     /* DMAC read/write width = 16-bit */
-
        u16 num_chipselect;
 };