Commit ff441129 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Greg Kroah-Hartman
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serial: sh-sci: Add DT support to DMA setup 



Add support for obtaining DMA channel information from the device tree.

This requires switching from the legacy sh_dmae_slave structures with
hardcoded channel numbers and the corresponding filter function to:
  1. dma_request_slave_channel_compat(),
       - On legacy platforms, dma_request_slave_channel_compat() uses
	 the passed DMA channel numbers that originate from platform
	 device data,
       - On DT-based platforms, dma_request_slave_channel_compat() will
	 retrieve the information from DT.
  2. and the generic dmaengine_slave_config() configuration method,
     which requires filling in DMA register ports and slave bus widths.

Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e7327c09

drivers/tty/serial/sh-sci.c

+47 −31
Original line number Diff line number Diff line
@@ -112,8 +112,6 @@ struct sci_port { 
	struct scatterlist		sg_rx[2];

	void				*rx_buf[2];

	size_t				buf_len_rx;

	struct sh_dmae_slave		param_tx;

	struct sh_dmae_slave		param_rx;

	struct work_struct		work_tx;

	struct timer_list		rx_timer;

	unsigned int			rx_timeout;
@@ -1263,17 +1261,6 @@ static void work_fn_tx(struct work_struct *work) 
	dma_async_issue_pending(chan);

}



static bool filter(struct dma_chan *chan, void *slave)

{

	struct sh_dmae_slave *param = slave;



	dev_dbg(chan->device->dev, "%s: slave ID %d\n",

		__func__, param->shdma_slave.slave_id);



	chan->private = &param->shdma_slave;

	return true;

}



static void rx_timer_fn(unsigned long arg)

{

	struct sci_port *s = (struct sci_port *)arg;
@@ -1347,28 +1334,62 @@ static void rx_timer_fn(unsigned long arg) 
	spin_unlock_irqrestore(&port->lock, flags);

}



static struct dma_chan *sci_request_dma_chan(struct uart_port *port,

					     enum dma_transfer_direction dir,

					     unsigned int id)

{

	dma_cap_mask_t mask;

	struct dma_chan *chan;

	struct dma_slave_config cfg;

	int ret;



	dma_cap_zero(mask);

	dma_cap_set(DMA_SLAVE, mask);



	chan = dma_request_slave_channel_compat(mask, shdma_chan_filter,

					(void *)(unsigned long)id, port->dev,

					dir == DMA_MEM_TO_DEV ? "tx" : "rx");

	if (!chan) {

		dev_warn(port->dev,

			 "dma_request_slave_channel_compat failed\n");

		return NULL;

	}



	memset(&cfg, 0, sizeof(cfg));

	cfg.direction = dir;

	if (dir == DMA_MEM_TO_DEV) {

		cfg.dst_addr = port->mapbase +

			(sci_getreg(port, SCxTDR)->offset << port->regshift);

		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;

	} else {

		cfg.src_addr = port->mapbase +

			(sci_getreg(port, SCxRDR)->offset << port->regshift);

		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;

	}



	ret = dmaengine_slave_config(chan, &cfg);

	if (ret) {

		dev_warn(port->dev, "dmaengine_slave_config failed %d\n", ret);

		dma_release_channel(chan);

		return NULL;

	}



	return chan;

}



static void sci_request_dma(struct uart_port *port)

{

	struct sci_port *s = to_sci_port(port);

	struct sh_dmae_slave *param;

	struct dma_chan *chan;

	dma_cap_mask_t mask;



	dev_dbg(port->dev, "%s: port %d\n", __func__, port->line);



	if (s->cfg->dma_slave_tx <= 0 || s->cfg->dma_slave_rx <= 0)

	if (!port->dev->of_node &&

	    (s->cfg->dma_slave_tx <= 0 || s->cfg->dma_slave_rx <= 0))

		return;



	dma_cap_zero(mask);

	dma_cap_set(DMA_SLAVE, mask);



	param = &s->param_tx;



	/* Slave ID, e.g., SHDMA_SLAVE_SCIF0_TX */

	param->shdma_slave.slave_id = s->cfg->dma_slave_tx;



	s->cookie_tx = -EINVAL;

	chan = dma_request_channel(mask, filter, param);

	chan = sci_request_dma_chan(port, DMA_MEM_TO_DEV, s->cfg->dma_slave_tx);

	dev_dbg(port->dev, "%s: TX: got channel %p\n", __func__, chan);

	if (chan) {

		s->chan_tx = chan;
@@ -1390,12 +1411,7 @@ static void sci_request_dma(struct uart_port *port) 
		INIT_WORK(&s->work_tx, work_fn_tx);

	}



	param = &s->param_rx;



	/* Slave ID, e.g., SHDMA_SLAVE_SCIF0_RX */

	param->shdma_slave.slave_id = s->cfg->dma_slave_rx;



	chan = dma_request_channel(mask, filter, param);

	chan = sci_request_dma_chan(port, DMA_DEV_TO_MEM, s->cfg->dma_slave_rx);

	dev_dbg(port->dev, "%s: RX: got channel %p\n", __func__, chan);

	if (chan) {

		unsigned int i;

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