Messages in this thread Patch in this message | | | From | Stephen Boyd <> | Subject | [PATCH v2] Input: elants_i2c - Use DMA safe i2c when possible | Date | Wed, 10 Oct 2018 12:59:27 -0700 |
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This irq handler is always reading bytes from the device into a kmalloced buffer, so it's safe to mark this transaction as DMA safe. This avoids bouncing the buffer when an i2c controller decides to use DMA for a transaction.
Cc: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Stephen Boyd <swboyd@chromium.org> ---
Changes from v1: * Moved buf to end of structure to keep it cacheline aligned and DMA safe
drivers/input/touchscreen/elants_i2c.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c index d21ca39b0fdb..f2cb23121833 100644 --- a/drivers/input/touchscreen/elants_i2c.c +++ b/drivers/input/touchscreen/elants_i2c.c @@ -147,10 +147,11 @@ struct elants_data { u8 cmd_resp[HEADER_SIZE]; struct completion cmd_done; - u8 buf[MAX_PACKET_SIZE]; - bool wake_irq_enabled; bool keep_power_in_suspend; + + /* Must be last to be used for DMA operations */ + u8 buf[MAX_PACKET_SIZE] ____cacheline_aligned; }; static int elants_i2c_send(struct i2c_client *client, @@ -863,7 +864,7 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev) int i; int len; - len = i2c_master_recv(client, ts->buf, sizeof(ts->buf)); + len = i2c_master_recv_dmasafe(client, ts->buf, sizeof(ts->buf)); if (len < 0) { dev_err(&client->dev, "%s: failed to read data: %d\n", __func__, len); -- Sent by a computer through tubes
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