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serial: 8250_dw: Enable DMA support with ACPI

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

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heikki Krogerus 2013-01-10 11:25:12 +02:00 committed by Greg Kroah-Hartman
parent 9ee4b83e51
commit 7277b2a1c6
1 changed files with 65 additions and 0 deletions
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65
drivers/tty/serial/8250/8250_dw.c
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@ -27,6 +27,8 @@
#include <linux/slab.h>
#include <linux/acpi.h>
#include "8250.h"
/* Offsets for the DesignWare specific registers */
#define DW_UART_USR 0x1f /* UART Status Register */
#define DW_UART_CPR 0xf4 /* Component Parameter Register */
@ -143,9 +145,64 @@ static int dw8250_probe_of(struct uart_port *p)
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)
{
const struct acpi_device_id *id;
acpi_status status;
u32 reg;
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->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 */
if (!strcmp(id->id, "INT33C4") || !strcmp(id->id, "INT33C5")) {
reg = readl(p->membase + LPSS_PRV_CLOCK_PARAMS);