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@xxxxxx> [s-anna@xxxxxx: revise logic and update comments/patch description] Signed-off-by: Suman Anna <s-anna@xxxxxx> --- .../devicetree/bindings/mailbox/omap-mailbox.txt | 8 ++++ drivers/mailbox/omap-mailbox.c | 49 ++++++++++++++++++++-- 2 files changed, 53 insertions(+), 4 deletions(-) diff --git a/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt b/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt index d1a0433..9b40c49 100644 --- a/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt +++ b/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt @@ -75,6 +75,14 @@ data that represent the following: Cell #3 (usr_id) - mailbox user id for identifying the interrupt line associated with generating a tx/rx fifo interrupt. +Optional Properties: +-------------------- +- ti,mbox-send-noirq: Quirk flag to allow the client user of this sub-mailbox + to send messages without triggering a Tx ready interrupt, + and to control the Tx ticker. Should be used only on + sub-mailboxes used to communicate with WkupM3 remote + processor on AM33xx/AM43xx SoCs. + Mailbox Users: ============== A device needing to communicate with a target processor device should specify diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c index a3dbfd9..b7f636f 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; -- 2.4.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html