From 38ed8c888e94f10e3a74a931760e77c0ab9d2e48 Mon Sep 17 00:00:00 2001 From: Hector Martin Date: Wed, 14 Sep 2022 09:34:21 +0100 Subject: [PATCH] mailbox: apple: Implement flush() operation This allows clients to use the atomic-safe mailbox API style. Signed-off-by: Hector Martin Signed-off-by: Russell King (Oracle) Signed-off-by: Jassi Brar --- drivers/mailbox/apple-mailbox.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/mailbox/apple-mailbox.c b/drivers/mailbox/apple-mailbox.c index 496c495..33e7acf 100644 --- a/drivers/mailbox/apple-mailbox.c +++ b/drivers/mailbox/apple-mailbox.c @@ -17,6 +17,7 @@ */ #include +#include #include #include #include @@ -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, }; -- 2.7.4