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serial: sh-sci: Use incrementing pointers instead of stack array

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There's no need to keep all buffer and DMA pointers on the stack.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Geert Uytterhoeven 2015-08-21 20:02:53 +02:00 committed by Greg Kroah-Hartman
parent 47b0e94a67
commit ba172c7045
1 changed files with 12 additions and 14 deletions
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26
drivers/tty/serial/sh-sci.c
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@ -1734,18 +1734,16 @@ static void sci_request_dma(struct uart_port *port)
chan = dma_request_channel(mask, filter, param);
dev_dbg(port->dev, "%s: RX: got channel %p\n", __func__, chan);
if (chan) {
dma_addr_t dma[2];
void *buf[2];
int i;
unsigned int i;
dma_addr_t dma;
void *buf;
s->chan_rx = chan;
s->buf_len_rx = 2 * max_t(size_t, 16, port->fifosize);
buf[0] = dma_alloc_coherent(chan->device->dev,
s->buf_len_rx * 2, &dma[0],
GFP_KERNEL);
if (!buf[0]) {
buf = dma_alloc_coherent(chan->device->dev, s->buf_len_rx * 2,
&dma, GFP_KERNEL);
if (!buf) {
dev_warn(port->dev,
"Failed to allocate Rx dma buffer, using PIO\n");
dma_release_channel(chan);
@ -1754,16 +1752,16 @@ static void sci_request_dma(struct uart_port *port)
return;
}
buf[1] = buf[0] + s->buf_len_rx;
dma[1] = dma[0] + s->buf_len_rx;
for (i = 0; i < 2; i++) {
struct scatterlist *sg = &s->sg_rx[i];
sg_init_table(sg, 1);
sg_set_page(sg, virt_to_page(buf[i]), s->buf_len_rx,
(uintptr_t)buf[i] & ~PAGE_MASK);
sg_dma_address(sg) = dma[i];
sg_set_page(sg, virt_to_page(buf), s->buf_len_rx,
(uintptr_t)buf & ~PAGE_MASK);
sg_dma_address(sg) = dma;
buf += s->buf_len_rx;
dma += s->buf_len_rx;
}
INIT_WORK(&s->work_rx, work_fn_rx);