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mailbox: apple: Implement flush() operation

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This allows clients to use the atomic-safe mailbox API style.

Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
This commit is contained in:
Hector Martin 2022-09-14 09:34:21 +01:00 committed by Jassi Brar
parent 3245cb65fd
commit 38ed8c888e
1 changed files with 27 additions and 0 deletions
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27
drivers/mailbox/apple-mailbox.c
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@ -17,6 +17,7 @@
*/
#include <linux/apple-mailbox.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gfp.h>
#include <linux/interrupt.h>
@ -112,6 +113,14 @@ static bool apple_mbox_hw_can_send(struct apple_mbox *apple_mbox)
return !(mbox_ctrl & apple_mbox->hw->control_full);
}
static bool apple_mbox_hw_send_empty(struct apple_mbox *apple_mbox)
{
u32 mbox_ctrl =
readl_relaxed(apple_mbox->regs + apple_mbox->hw->a2i_control);
return mbox_ctrl & apple_mbox->hw->control_empty;
}
static int apple_mbox_hw_send(struct apple_mbox *apple_mbox,
struct apple_mbox_msg *msg)
{
@ -219,6 +228,23 @@ static irqreturn_t apple_mbox_recv_irq(int irq, void *data)
return IRQ_HANDLED;
}
static int apple_mbox_chan_flush(struct mbox_chan *chan, unsigned long timeout)
{
struct apple_mbox *apple_mbox = chan->con_priv;
unsigned long deadline = jiffies + msecs_to_jiffies(timeout);
while (time_before(jiffies, deadline)) {
if (apple_mbox_hw_send_empty(apple_mbox)) {
mbox_chan_txdone(&apple_mbox->chan, 0);
return 0;
}
udelay(1);
}
return -ETIME;
}
static int apple_mbox_chan_startup(struct mbox_chan *chan)
{
struct apple_mbox *apple_mbox = chan->con_priv;
@ -250,6 +276,7 @@ static void apple_mbox_chan_shutdown(struct mbox_chan *chan)
static const struct mbox_chan_ops apple_mbox_ops = {
.send_data = apple_mbox_chan_send_data,
.flush = apple_mbox_chan_flush,
.startup = apple_mbox_chan_startup,
.shutdown = apple_mbox_chan_shutdown,
};