From: Feng Tang <feng.tang@xxxxxxxxx>
The three identical uart ports can work either in DMA or PIO mode. Adding such
a module parameter "hsu_dma_enable" will enable user to chose working modes for
each port. If the mfd driver is built in kernel, adding a "mfd.hsu_dma_enable=x"
in kernel command line has the same effect.
Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/tty/serial/mfd.c | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/drivers/tty/serial/mfd.c b/drivers/tty/serial/mfd.c
index 53ff6af..c111f36 100644
--- a/drivers/tty/serial/mfd.c
+++ b/drivers/tty/serial/mfd.c
@@ -47,6 +47,11 @@
#define mfd_readl(obj, offset) readl(obj->reg + offset)
#define mfd_writel(obj, offset, val) writel(val, obj->reg + offset)
+static int hsu_dma_enable;
+module_param(hsu_dma_enable, int, 0);
+MODULE_PARM_DESC(hsu_dma_enable, "It is a bitmap to set working mode, if \
+bit[x] is 1, then port[x] will work in DMA mode, otherwise in PIO mode.");
+
struct hsu_dma_buffer {
u8 *buf;
dma_addr_t dma_addr;
@@ -1367,6 +1372,12 @@ static void hsu_global_init(void)
serial_hsu_ports[i] = uport;
uport->index = i;
+
+ if (hsu_dma_enable & (1<<i))
+ uport->use_dma = 1;
+ else
+ uport->use_dma = 0;
+
uport++;
}
--
1.7.4.1
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