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https://github.com/torvalds/linux
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f62092f6d7
The Altera mailbox allows for interprocessor communication. It supports only one channel and work as either sender or receiver. Signed-off-by: Ley Foon Tan <lftan@altera.com>
388 lines
9.2 KiB
C
388 lines
9.2 KiB
C
/*
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* Copyright Altera Corporation (C) 2013-2014. All rights reserved
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/device.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/mailbox_controller.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#define DRIVER_NAME "altera-mailbox"
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#define MAILBOX_CMD_REG 0x00
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#define MAILBOX_PTR_REG 0x04
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#define MAILBOX_STS_REG 0x08
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#define MAILBOX_INTMASK_REG 0x0C
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#define INT_PENDING_MSK 0x1
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#define INT_SPACE_MSK 0x2
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#define STS_PENDING_MSK 0x1
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#define STS_FULL_MSK 0x2
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#define STS_FULL_OFT 0x1
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#define MBOX_PENDING(status) (((status) & STS_PENDING_MSK))
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#define MBOX_FULL(status) (((status) & STS_FULL_MSK) >> STS_FULL_OFT)
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enum altera_mbox_msg {
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MBOX_CMD = 0,
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MBOX_PTR,
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};
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#define MBOX_POLLING_MS 5 /* polling interval 5ms */
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struct altera_mbox {
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bool is_sender; /* 1-sender, 0-receiver */
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bool intr_mode;
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int irq;
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void __iomem *mbox_base;
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struct device *dev;
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struct mbox_controller controller;
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/* If the controller supports only RX polling mode */
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struct timer_list rxpoll_timer;
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};
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static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan)
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{
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if (!chan || !chan->con_priv)
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return NULL;
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return (struct altera_mbox *)chan->con_priv;
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}
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static inline int altera_mbox_full(struct altera_mbox *mbox)
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{
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u32 status;
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status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
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return MBOX_FULL(status);
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}
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static inline int altera_mbox_pending(struct altera_mbox *mbox)
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{
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u32 status;
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status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
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return MBOX_PENDING(status);
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}
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static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
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{
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u32 mask;
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mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
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if (enable)
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mask |= INT_PENDING_MSK;
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else
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mask &= ~INT_PENDING_MSK;
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writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
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}
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static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
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{
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u32 mask;
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mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
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if (enable)
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mask |= INT_SPACE_MSK;
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else
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mask &= ~INT_SPACE_MSK;
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writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
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}
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static bool altera_mbox_is_sender(struct altera_mbox *mbox)
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{
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u32 reg;
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/* Write a magic number to PTR register and read back this register.
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* This register is read-write if it is a sender.
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*/
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#define MBOX_MAGIC 0xA5A5AA55
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writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
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reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
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if (reg == MBOX_MAGIC) {
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/* Clear to 0 */
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writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
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return true;
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}
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return false;
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}
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static void altera_mbox_rx_data(struct mbox_chan *chan)
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{
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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u32 data[2];
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if (altera_mbox_pending(mbox)) {
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data[MBOX_PTR] =
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readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
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data[MBOX_CMD] =
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readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
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mbox_chan_received_data(chan, (void *)data);
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}
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}
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static void altera_mbox_poll_rx(unsigned long data)
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{
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struct mbox_chan *chan = (struct mbox_chan *)data;
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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altera_mbox_rx_data(chan);
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mod_timer(&mbox->rxpoll_timer,
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jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
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}
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static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p)
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{
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struct mbox_chan *chan = (struct mbox_chan *)p;
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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altera_mbox_tx_intmask(mbox, false);
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mbox_chan_txdone(chan, 0);
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return IRQ_HANDLED;
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}
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static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p)
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{
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struct mbox_chan *chan = (struct mbox_chan *)p;
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altera_mbox_rx_data(chan);
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return IRQ_HANDLED;
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}
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static int altera_mbox_startup_sender(struct mbox_chan *chan)
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{
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int ret;
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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if (mbox->intr_mode) {
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ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,
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DRIVER_NAME, chan);
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if (unlikely(ret)) {
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dev_err(mbox->dev,
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"failed to register mailbox interrupt:%d\n",
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ret);
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return ret;
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}
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}
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return 0;
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}
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static int altera_mbox_startup_receiver(struct mbox_chan *chan)
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{
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int ret;
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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if (mbox->intr_mode) {
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ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
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DRIVER_NAME, chan);
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if (unlikely(ret)) {
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mbox->intr_mode = false;
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goto polling; /* use polling if failed */
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}
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altera_mbox_rx_intmask(mbox, true);
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return 0;
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}
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polling:
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/* Setup polling timer */
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setup_timer(&mbox->rxpoll_timer, altera_mbox_poll_rx,
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(unsigned long)chan);
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mod_timer(&mbox->rxpoll_timer,
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jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
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return 0;
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}
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static int altera_mbox_send_data(struct mbox_chan *chan, void *data)
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{
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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u32 *udata = (u32 *)data;
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if (!mbox || !data)
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return -EINVAL;
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if (!mbox->is_sender) {
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dev_warn(mbox->dev,
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"failed to send. This is receiver mailbox.\n");
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return -EINVAL;
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}
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if (altera_mbox_full(mbox))
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return -EBUSY;
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/* Enable interrupt before send */
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if (mbox->intr_mode)
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altera_mbox_tx_intmask(mbox, true);
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/* Pointer register must write before command register */
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writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
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writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG);
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return 0;
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}
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static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
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{
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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/* Return false if mailbox is full */
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return altera_mbox_full(mbox) ? false : true;
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}
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static bool altera_mbox_peek_data(struct mbox_chan *chan)
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{
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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return altera_mbox_pending(mbox) ? true : false;
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}
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static int altera_mbox_startup(struct mbox_chan *chan)
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{
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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int ret = 0;
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if (!mbox)
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return -EINVAL;
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if (mbox->is_sender)
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ret = altera_mbox_startup_sender(chan);
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else
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ret = altera_mbox_startup_receiver(chan);
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return ret;
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}
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static void altera_mbox_shutdown(struct mbox_chan *chan)
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{
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struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
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if (mbox->intr_mode) {
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/* Unmask all interrupt masks */
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writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
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free_irq(mbox->irq, chan);
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} else if (!mbox->is_sender) {
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del_timer_sync(&mbox->rxpoll_timer);
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}
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}
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static struct mbox_chan_ops altera_mbox_ops = {
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.send_data = altera_mbox_send_data,
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.startup = altera_mbox_startup,
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.shutdown = altera_mbox_shutdown,
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.last_tx_done = altera_mbox_last_tx_done,
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.peek_data = altera_mbox_peek_data,
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};
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static int altera_mbox_probe(struct platform_device *pdev)
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{
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struct altera_mbox *mbox;
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struct resource *regs;
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struct mbox_chan *chans;
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int ret;
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mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox),
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GFP_KERNEL);
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if (!mbox)
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return -ENOMEM;
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/* Allocated one channel */
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chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
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if (!chans)
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return -ENOMEM;
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regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
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if (IS_ERR(mbox->mbox_base))
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return PTR_ERR(mbox->mbox_base);
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/* Check is it a sender or receiver? */
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mbox->is_sender = altera_mbox_is_sender(mbox);
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mbox->irq = platform_get_irq(pdev, 0);
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if (mbox->irq >= 0)
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mbox->intr_mode = true;
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mbox->dev = &pdev->dev;
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/* Hardware supports only one channel. */
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chans[0].con_priv = mbox;
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mbox->controller.dev = mbox->dev;
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mbox->controller.num_chans = 1;
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mbox->controller.chans = chans;
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mbox->controller.ops = &altera_mbox_ops;
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if (mbox->is_sender) {
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if (mbox->intr_mode) {
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mbox->controller.txdone_irq = true;
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} else {
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mbox->controller.txdone_poll = true;
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mbox->controller.txpoll_period = MBOX_POLLING_MS;
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}
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}
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ret = mbox_controller_register(&mbox->controller);
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if (ret) {
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dev_err(&pdev->dev, "Register mailbox failed\n");
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goto err;
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}
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platform_set_drvdata(pdev, mbox);
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err:
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return ret;
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}
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static int altera_mbox_remove(struct platform_device *pdev)
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{
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struct altera_mbox *mbox = platform_get_drvdata(pdev);
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if (!mbox)
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return -EINVAL;
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mbox_controller_unregister(&mbox->controller);
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return 0;
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}
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static const struct of_device_id altera_mbox_match[] = {
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{ .compatible = "altr,mailbox-1.0" },
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{ /* Sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, altera_mbox_match);
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static struct platform_driver altera_mbox_driver = {
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.probe = altera_mbox_probe,
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.remove = altera_mbox_remove,
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.driver = {
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.name = DRIVER_NAME,
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.of_match_table = altera_mbox_match,
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},
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};
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module_platform_driver(altera_mbox_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("Altera mailbox specific functions");
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MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
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MODULE_ALIAS("platform:altera-mailbox");
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