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364 lines
8.5 KiB
364 lines
8.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright Altera Corporation (C) 2013-2014. All rights reserved |
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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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struct mbox_chan *chan; |
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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(struct timer_list *t) |
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{ |
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struct altera_mbox *mbox = from_timer(mbox, t, rxpoll_timer); |
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altera_mbox_rx_data(mbox->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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mbox->chan = chan; |
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timer_setup(&mbox->rxpoll_timer, altera_mbox_poll_rx, 0); |
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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 const 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 = devm_mbox_controller_register(&pdev->dev, &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 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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.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 <[email protected]>"); |
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MODULE_ALIAS("platform:altera-mailbox");
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