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Commit 7277b2a1 authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman
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serial: 8250_dw: Enable DMA support with ACPI 



With ACPI 5.0 we can use the FixedDMA Resource Descriptor to
extract the needed information for DMA support.

Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9ee4b83e

drivers/tty/serial/8250/8250_dw.c

+65 −0
Original line number Original line Diff line number Diff line
@@ -27,6 +27,8 @@ 
#include <linux/slab.h>

#include <linux/slab.h>

#include <linux/acpi.h>

#include <linux/acpi.h>





#include "8250.h"



/* Offsets for the DesignWare specific registers */

/* Offsets for the DesignWare specific registers */

#define DW_UART_USR	0x1f /* UART Status Register */

#define DW_UART_USR	0x1f /* UART Status Register */

#define DW_UART_CPR	0xf4 /* Component Parameter Register */

#define DW_UART_CPR	0xf4 /* Component Parameter Register */
@@ -143,9 +145,64 @@ static int dw8250_probe_of(struct uart_port *p) 
	return 0;

	return 0;

}

}





static bool dw8250_acpi_dma_filter(struct dma_chan *chan, void *parm)

{

	return chan->chan_id == *(int *)parm;

}



static acpi_status

dw8250_acpi_walk_resource(struct acpi_resource *res, void *data)

{

	struct uart_port		*p = data;

	struct uart_8250_port		*port;

	struct uart_8250_dma		*dma;

	struct acpi_resource_fixed_dma	*fixed_dma;

	struct dma_slave_config		*slave;



	port = container_of(p, struct uart_8250_port, port);



	switch (res->type) {

	case ACPI_RESOURCE_TYPE_FIXED_DMA:

		fixed_dma = &res->data.fixed_dma;



		/* TX comes first */

		if (!port->dma) {

			dma = devm_kzalloc(p->dev, sizeof(*dma), GFP_KERNEL);

			if (!dma)

				return AE_NO_MEMORY;



			port->dma = dma;

			slave = &dma->txconf;



			slave->direction	= DMA_MEM_TO_DEV;

			slave->dst_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;

			slave->slave_id		= fixed_dma->request_lines;



			dma->tx_chan_id		= fixed_dma->channels;

			dma->tx_param		= &dma->tx_chan_id;

			dma->fn			= dw8250_acpi_dma_filter;

		} else {

			dma = port->dma;

			slave = &dma->rxconf;



			slave->direction	= DMA_DEV_TO_MEM;

			slave->src_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;

			slave->slave_id		= fixed_dma->request_lines;



			dma->rx_chan_id		= fixed_dma->channels;

			dma->rx_param		= &dma->rx_chan_id;

		}



		break;

	}



	return AE_OK;

}



static int dw8250_probe_acpi(struct uart_port *p)

static int dw8250_probe_acpi(struct uart_port *p)

{

{

	const struct acpi_device_id *id;

	const struct acpi_device_id *id;

	acpi_status status;

	u32 reg;

	u32 reg;





	id = acpi_match_device(p->dev->driver->acpi_match_table, p->dev);

	id = acpi_match_device(p->dev->driver->acpi_match_table, p->dev);
@@ -158,6 +215,14 @@ static int dw8250_probe_acpi(struct uart_port *p) 
	p->regshift = 2;

	p->regshift = 2;

	p->uartclk = (unsigned int)id->driver_data;

	p->uartclk = (unsigned int)id->driver_data;





	status = acpi_walk_resources(ACPI_HANDLE(p->dev), METHOD_NAME__CRS,

				     dw8250_acpi_walk_resource, p);

	if (ACPI_FAILURE(status)) {

		dev_err_ratelimited(p->dev, "%s failed \"%s\"\n", __func__,

				    acpi_format_exception(status));

		return -ENODEV;

	}



	/* Fix Haswell issue where the clocks do not get enabled */

	/* Fix Haswell issue where the clocks do not get enabled */

	if (!strcmp(id->id, "INT33C4") || !strcmp(id->id, "INT33C5")) {

	if (!strcmp(id->id, "INT33C4") || !strcmp(id->id, "INT33C5")) {

		reg = readl(p->membase + LPSS_PRV_CLOCK_PARAMS);

		reg = readl(p->membase + LPSS_PRV_CLOCK_PARAMS);