Commit 9c5de2c1 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Mark Brown
Browse files

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: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 32c64261

drivers/spi/spi-rspi.c

+6 −78
Original line number Diff line number Diff line
@@ -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);

include/linux/spi/rspi.h

+0 −2
Original line number Diff line number Diff line
@@ -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;

};

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