From patchwork Fri Nov 2 12:32:32 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vaibhav Bedia X-Patchwork-Id: 1688251 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 1ACCEDF2A2 for ; Fri, 2 Nov 2012 12:34:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760809Ab2KBMeX (ORCPT ); Fri, 2 Nov 2012 08:34:23 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:39656 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755498Ab2KBMeV (ORCPT ); Fri, 2 Nov 2012 08:34:21 -0400 Received: from dbdp20.itg.ti.com ([172.24.170.38]) by arroyo.ext.ti.com (8.13.7/8.13.7) with ESMTP id qA2CYDvG021957; Fri, 2 Nov 2012 07:34:14 -0500 Received: from DBDE71.ent.ti.com (localhost [127.0.0.1]) by dbdp20.itg.ti.com (8.13.8/8.13.8) with ESMTP id qA2CYAs9022142; Fri, 2 Nov 2012 18:04:13 +0530 (IST) Received: from dbdp32.itg.ti.com (172.24.170.251) by DBDE71.ent.ti.com (172.24.170.149) with Microsoft SMTP Server id 14.1.323.3; Fri, 2 Nov 2012 18:04:10 +0530 Received: from localhost.localdomain (dbdp20.itg.ti.com [172.24.170.38]) by dbdp32.itg.ti.com (8.13.8/8.13.8) with ESMTP id qA2CY79B022950; Fri, 2 Nov 2012 18:04:10 +0530 From: Vaibhav Bedia To: , CC: , , , , Vaibhav Bedia Subject: [PATCH 01/15] ARM: OMAP2+: mailbox: Add an API for flushing the FIFO Date: Fri, 2 Nov 2012 18:02:32 +0530 Message-ID: <1351859566-24818-2-git-send-email-vaibhav.bedia@ti.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1351859566-24818-1-git-send-email-vaibhav.bedia@ti.com> References: <1351859566-24818-1-git-send-email-vaibhav.bedia@ti.com> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org On AM33XX, the mailbox module between the MPU and the WKUP-M3 co-processor facilitates a one-way communication. MPU uses the assigned mailbox sub-module to issue the interrupt to the WKUP-M3 co-processor which then goes and reads the the IPC data from registers in the control module. WKUP-M3 is in the L4_WKUP and does not have any access to the Mailbox module. Due to this limitation, the MPU is completely responsible for FIFO maintenance and interrupt generation. MPU needs to ensure that the FIFO does not overflow by reading by the assigned mailbox sub-module. This patch adds an API in the mailbox code which the MPU can use to empty the FIFO by issuing a readback command. Signed-off-by: Vaibhav Bedia --- arch/arm/mach-omap2/mailbox.c | 42 ++++++++++++++++++++--------- arch/arm/plat-omap/include/plat/mailbox.h | 3 ++ arch/arm/plat-omap/mailbox.c | 35 ++++++++++++++++++++++++ 3 files changed, 67 insertions(+), 13 deletions(-) diff --git a/arch/arm/mach-omap2/mailbox.c b/arch/arm/mach-omap2/mailbox.c index 0d97456..f38b4fa 100644 --- a/arch/arm/mach-omap2/mailbox.c +++ b/arch/arm/mach-omap2/mailbox.c @@ -123,6 +123,20 @@ static int omap2_mbox_fifo_full(struct omap_mbox *mbox) return mbox_read_reg(fifo->fifo_stat); } +static int omap2_mbox_fifo_needs_flush(struct omap_mbox *mbox) +{ + struct omap_mbox2_fifo *fifo = + &((struct omap_mbox2_priv *)mbox->priv)->tx_fifo; + return mbox_read_reg(fifo->msg_stat); +} + +static mbox_msg_t omap2_mbox_fifo_readback(struct omap_mbox *mbox) +{ + struct omap_mbox2_fifo *fifo = + &((struct omap_mbox2_priv *)mbox->priv)->tx_fifo; + return (mbox_msg_t) mbox_read_reg(fifo->msg); +} + /* Mailbox IRQ handle functions */ static void omap2_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_type_t irq) @@ -205,19 +219,21 @@ static void omap2_mbox_restore_ctx(struct omap_mbox *mbox) } static struct omap_mbox_ops omap2_mbox_ops = { - .type = OMAP_MBOX_TYPE2, - .startup = omap2_mbox_startup, - .shutdown = omap2_mbox_shutdown, - .fifo_read = omap2_mbox_fifo_read, - .fifo_write = omap2_mbox_fifo_write, - .fifo_empty = omap2_mbox_fifo_empty, - .fifo_full = omap2_mbox_fifo_full, - .enable_irq = omap2_mbox_enable_irq, - .disable_irq = omap2_mbox_disable_irq, - .ack_irq = omap2_mbox_ack_irq, - .is_irq = omap2_mbox_is_irq, - .save_ctx = omap2_mbox_save_ctx, - .restore_ctx = omap2_mbox_restore_ctx, + .type = OMAP_MBOX_TYPE2, + .startup = omap2_mbox_startup, + .shutdown = omap2_mbox_shutdown, + .fifo_read = omap2_mbox_fifo_read, + .fifo_write = omap2_mbox_fifo_write, + .fifo_empty = omap2_mbox_fifo_empty, + .fifo_full = omap2_mbox_fifo_full, + .fifo_needs_flush = omap2_mbox_fifo_needs_flush, + .fifo_readback = omap2_mbox_fifo_readback, + .enable_irq = omap2_mbox_enable_irq, + .disable_irq = omap2_mbox_disable_irq, + .ack_irq = omap2_mbox_ack_irq, + .is_irq = omap2_mbox_is_irq, + .save_ctx = omap2_mbox_save_ctx, + .restore_ctx = omap2_mbox_restore_ctx, }; /* diff --git a/arch/arm/plat-omap/include/plat/mailbox.h b/arch/arm/plat-omap/include/plat/mailbox.h index cc3921e..e136529 100644 --- a/arch/arm/plat-omap/include/plat/mailbox.h +++ b/arch/arm/plat-omap/include/plat/mailbox.h @@ -29,6 +29,8 @@ struct omap_mbox_ops { void (*fifo_write)(struct omap_mbox *mbox, mbox_msg_t msg); int (*fifo_empty)(struct omap_mbox *mbox); int (*fifo_full)(struct omap_mbox *mbox); + int (*fifo_needs_flush)(struct omap_mbox *mbox); + mbox_msg_t (*fifo_readback)(struct omap_mbox *mbox); /* irq */ void (*enable_irq)(struct omap_mbox *mbox, omap_mbox_irq_t irq); @@ -61,6 +63,7 @@ struct omap_mbox { struct blocking_notifier_head notifier; }; +int omap_mbox_msg_rx_flush(struct omap_mbox *mbox); int omap_mbox_msg_send(struct omap_mbox *, mbox_msg_t msg); void omap_mbox_init_seq(struct omap_mbox *); diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c index 42377ef..cb9754a 100644 --- a/arch/arm/plat-omap/mailbox.c +++ b/arch/arm/plat-omap/mailbox.c @@ -59,6 +59,14 @@ static inline int mbox_fifo_full(struct omap_mbox *mbox) { return mbox->ops->fifo_full(mbox); } +static inline int mbox_fifo_needs_flush(struct omap_mbox *mbox) +{ + return mbox->ops->fifo_needs_flush(mbox); +} +static inline mbox_msg_t mbox_fifo_readback(struct omap_mbox *mbox) +{ + return mbox->ops->fifo_readback(mbox); +} /* Mailbox IRQ handle functions */ static inline void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq) @@ -116,6 +124,33 @@ out: } EXPORT_SYMBOL(omap_mbox_msg_send); +/* + * Flush the Rx FIFO by reading back the messages + * Since the normal expectation is that the Rx will do the + * reading, add a debug message to indicate if we really flush + * + * Returns the no. of messages read back + */ +int omap_mbox_msg_rx_flush(struct omap_mbox *mbox) +{ + int ret = 0; + mbox_msg_t msg; + + while (mbox_fifo_needs_flush(mbox)) { + msg = mbox_fifo_readback(mbox); + ret++; + } + + if (ret) { + /* no more messages in the fifo. clear IRQ source. */ + ack_mbox_irq(mbox, IRQ_RX); + pr_debug("Flushed %s Rx FIFO by reading back\n", mbox->name); + } + + return ret; +} +EXPORT_SYMBOL(omap_mbox_msg_rx_flush); + static void mbox_tx_tasklet(unsigned long tx_data) { struct omap_mbox *mbox = (struct omap_mbox *)tx_data;