| Message ID | 20181010200017.255874-1-swboyd@chromium.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] Input: elants_i2c - Use DMA safe i2c when possible | expand |
On Wed, Oct 10, 2018 at 01:00:17PM -0700, Stephen Boyd wrote: > 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> Changed patch description a bit (now that we are actually making the buffer DMA-safe) and applied, thank you. > --- > > 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 >
On Wed, Oct 10, 2018 at 01:00:17PM -0700, Stephen Boyd wrote: > 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> For the record: Acked-by: Wolfram Sang <wsa@the-dreams.de>
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);
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(-)