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@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_dw.c | 65 +++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index f6eeff0..ceacf5e 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -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);
--
1.7.10.4
--
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