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authorDave Gerlach <d-gerlach@ti.com>2015-09-22 19:14:52 -0500
committerJassi Brar <jaswinder.singh@linaro.org>2015-10-23 11:19:27 +0530
commit8e3c5952144f045a0c81bf674d3f5e1d9aafceb7 (patch)
tree56542626b3ca34a7087eeccfb7d83f7734e67ee3 /drivers/mailbox
parenta133f8b65d591101e48336050ceb7e2f51026502 (diff)
downloadlinux-8e3c5952144f045a0c81bf674d3f5e1d9aafceb7.tar.bz2
mailbox/omap: Add ti,mbox-send-noirq quirk to fix AM33xx CPU Idle
The mailbox framework controls the transmission queue and requires either its controller implementations or clients to run the state machine for the Tx queue. The OMAP mailbox controller uses a Tx-ready interrupt as the equivalent of a Tx-done interrupt to run this Tx queue state-machine. The WkupM3 processor on AM33xx and AM43xx SoCs is used to offload certain PM tasks, like doing the necessary operations for Device PM suspend/resume or for entering lower c-states during cpuidle. The CPUIdle on AM33xx requires the messages to be sent without having to trigger the Tx-ready interrupts, as the interrupt would immediately terminate the CPUIdle operation. Support for this has been added by introducing a DT quirk, "ti,mbox-send-noirq" and using it to modify the normal OMAP mailbox controller behavior on the sub-mailboxes used to communicate with the WkupM3 remote processor. This also requires the wkup_m3_ipc driver to adjust its mailbox usage logic to run the Tx state machine. NOTE: - AM43xx does not communicate with WkupM3 for CPU Idle, so is not affected by this behavior. But, it uses the same IPC driver for PM suspend/resume functionality, so requires the quirk as well, because of changes to the common wkup_m3_ipc driver. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> [s-anna@ti.com: revise logic and update comments/patch description] Signed-off-by: Suman Anna <s-anna@ti.com> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Diffstat (limited to 'drivers/mailbox')
-rw-r--r--drivers/mailbox/omap-mailbox.c49
1 files changed, 45 insertions, 4 deletions
diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index a3dbfd9c6479..b7f636f15cac 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -38,6 +38,8 @@
#include <linux/mailbox_controller.h>
#include <linux/mailbox_client.h>
+#include "mailbox.h"
+
#define MAILBOX_REVISION 0x000
#define MAILBOX_MESSAGE(m) (0x040 + 4 * (m))
#define MAILBOX_FIFOSTATUS(m) (0x080 + 4 * (m))
@@ -106,6 +108,7 @@ struct omap_mbox_fifo_info {
int rx_irq;
const char *name;
+ bool send_no_irq;
};
struct omap_mbox {
@@ -119,6 +122,7 @@ struct omap_mbox {
u32 ctx[OMAP4_MBOX_NR_REGS];
u32 intr_type;
struct mbox_chan *chan;
+ bool send_no_irq;
};
/* global variables for the mailbox devices */
@@ -418,6 +422,9 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
goto fail_request_irq;
}
+ if (mbox->send_no_irq)
+ mbox->chan->txdone_method = TXDONE_BY_ACK;
+
_omap_mbox_enable_irq(mbox, IRQ_RX);
return 0;
@@ -586,13 +593,27 @@ static void omap_mbox_chan_shutdown(struct mbox_chan *chan)
mutex_unlock(&mdev->cfg_lock);
}
-static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
+static int omap_mbox_chan_send_noirq(struct omap_mbox *mbox, void *data)
{
- struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
int ret = -EBUSY;
- if (!mbox)
- return -EINVAL;
+ if (!mbox_fifo_full(mbox)) {
+ _omap_mbox_enable_irq(mbox, IRQ_RX);
+ mbox_fifo_write(mbox, (mbox_msg_t)data);
+ ret = 0;
+ _omap_mbox_disable_irq(mbox, IRQ_RX);
+
+ /* we must read and ack the interrupt directly from here */
+ mbox_fifo_read(mbox);
+ ack_mbox_irq(mbox, IRQ_RX);
+ }
+
+ return ret;
+}
+
+static int omap_mbox_chan_send(struct omap_mbox *mbox, void *data)
+{
+ int ret = -EBUSY;
if (!mbox_fifo_full(mbox)) {
mbox_fifo_write(mbox, (mbox_msg_t)data);
@@ -604,6 +625,22 @@ static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
return ret;
}
+static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
+{
+ struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
+ int ret;
+
+ if (!mbox)
+ return -EINVAL;
+
+ if (mbox->send_no_irq)
+ ret = omap_mbox_chan_send_noirq(mbox, data);
+ else
+ ret = omap_mbox_chan_send(mbox, data);
+
+ return ret;
+}
+
static const struct mbox_chan_ops omap_mbox_chan_ops = {
.startup = omap_mbox_chan_startup,
.send_data = omap_mbox_chan_send_data,
@@ -732,6 +769,9 @@ static int omap_mbox_probe(struct platform_device *pdev)
finfo->rx_usr = tmp[2];
finfo->name = child->name;
+
+ if (of_find_property(child, "ti,mbox-send-noirq", NULL))
+ finfo->send_no_irq = true;
} else {
finfo->tx_id = info->tx_id;
finfo->rx_id = info->rx_id;
@@ -791,6 +831,7 @@ static int omap_mbox_probe(struct platform_device *pdev)
fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, finfo->rx_usr);
fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, finfo->rx_usr);
+ mbox->send_no_irq = finfo->send_no_irq;
mbox->intr_type = intr_type;
mbox->parent = mdev;