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ab47d0bfdf
Some services explicitly return an error code in their response, but
others rely on the system controller to set a status in its status
register. The meaning of the bits varies based on what service is
requested, so pass it back up to the driver that requested the service
in the first place. The field in the message struct already existed, but
was unused until now.
If the system controller is busy, in which case we should never actually
be in the interrupt handler, or if the service fails the mailbox itself
should not be read. Callers should check the status before operating on
the response.
There's an existing, but unused, #define for the mailbox mask - but it
was incorrect. It was doing a GENMASK_ULL(32, 16) which should've just
been a GENMASK(31, 16), so fix that up and start using it.
Fixes: 83d7b15608 ("mbox: add polarfire soc system controller mailbox")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
280 lines
7.3 KiB
C
280 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Microchip PolarFire SoC (MPFS) system controller/mailbox controller driver
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*
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* Copyright (c) 2020-2022 Microchip Corporation. All rights reserved.
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*
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* Author: Conor Dooley <conor.dooley@microchip.com>
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*
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*/
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#include <linux/io.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/mailbox_controller.h>
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#include <soc/microchip/mpfs.h>
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#define SERVICES_CR_OFFSET 0x50u
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#define SERVICES_SR_OFFSET 0x54u
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#define MAILBOX_REG_OFFSET 0x800u
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#define MSS_SYS_MAILBOX_DATA_OFFSET 0u
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#define SCB_MASK_WIDTH 16u
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/* SCBCTRL service control register */
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#define SCB_CTRL_REQ (0)
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#define SCB_CTRL_REQ_MASK BIT(SCB_CTRL_REQ)
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#define SCB_CTRL_BUSY (1)
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#define SCB_CTRL_BUSY_MASK BIT(SCB_CTRL_BUSY)
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#define SCB_CTRL_ABORT (2)
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#define SCB_CTRL_ABORT_MASK BIT(SCB_CTRL_ABORT)
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#define SCB_CTRL_NOTIFY (3)
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#define SCB_CTRL_NOTIFY_MASK BIT(SCB_CTRL_NOTIFY)
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#define SCB_CTRL_POS (16)
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#define SCB_CTRL_MASK GENMASK_ULL(SCB_CTRL_POS + SCB_MASK_WIDTH, SCB_CTRL_POS)
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/* SCBCTRL service status register */
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#define SCB_STATUS_REQ (0)
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#define SCB_STATUS_REQ_MASK BIT(SCB_STATUS_REQ)
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#define SCB_STATUS_BUSY (1)
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#define SCB_STATUS_BUSY_MASK BIT(SCB_STATUS_BUSY)
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#define SCB_STATUS_ABORT (2)
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#define SCB_STATUS_ABORT_MASK BIT(SCB_STATUS_ABORT)
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#define SCB_STATUS_NOTIFY (3)
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#define SCB_STATUS_NOTIFY_MASK BIT(SCB_STATUS_NOTIFY)
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#define SCB_STATUS_POS (16)
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#define SCB_STATUS_MASK GENMASK(SCB_STATUS_POS + SCB_MASK_WIDTH - 1, SCB_STATUS_POS)
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struct mpfs_mbox {
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struct mbox_controller controller;
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struct device *dev;
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int irq;
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void __iomem *ctrl_base;
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void __iomem *mbox_base;
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void __iomem *int_reg;
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struct mbox_chan chans[1];
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struct mpfs_mss_response *response;
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u16 resp_offset;
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};
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static bool mpfs_mbox_busy(struct mpfs_mbox *mbox)
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{
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u32 status;
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status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
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return status & SCB_STATUS_BUSY_MASK;
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}
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static int mpfs_mbox_send_data(struct mbox_chan *chan, void *data)
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{
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struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
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struct mpfs_mss_msg *msg = data;
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u32 tx_trigger;
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u16 opt_sel;
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u32 val = 0u;
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mbox->response = msg->response;
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mbox->resp_offset = msg->resp_offset;
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if (mpfs_mbox_busy(mbox))
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return -EBUSY;
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if (msg->cmd_data_size) {
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u32 index;
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u8 extra_bits = msg->cmd_data_size & 3;
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u32 *word_buf = (u32 *)msg->cmd_data;
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for (index = 0; index < (msg->cmd_data_size / 4); index++)
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writel_relaxed(word_buf[index],
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mbox->mbox_base + msg->mbox_offset + index * 0x4);
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if (extra_bits) {
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u8 i;
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u8 byte_off = ALIGN_DOWN(msg->cmd_data_size, 4);
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u8 *byte_buf = msg->cmd_data + byte_off;
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val = readl_relaxed(mbox->mbox_base + msg->mbox_offset + index * 0x4);
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for (i = 0u; i < extra_bits; i++) {
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val &= ~(0xffu << (i * 8u));
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val |= (byte_buf[i] << (i * 8u));
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}
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writel_relaxed(val, mbox->mbox_base + msg->mbox_offset + index * 0x4);
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}
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}
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opt_sel = ((msg->mbox_offset << 7u) | (msg->cmd_opcode & 0x7fu));
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tx_trigger = (opt_sel << SCB_CTRL_POS) & SCB_CTRL_MASK;
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tx_trigger |= SCB_CTRL_REQ_MASK | SCB_STATUS_NOTIFY_MASK;
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writel_relaxed(tx_trigger, mbox->ctrl_base + SERVICES_CR_OFFSET);
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return 0;
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}
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static void mpfs_mbox_rx_data(struct mbox_chan *chan)
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{
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struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
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struct mpfs_mss_response *response = mbox->response;
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u16 num_words = ALIGN((response->resp_size), (4)) / 4U;
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u32 i, status;
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if (!response->resp_msg) {
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dev_err(mbox->dev, "failed to assign memory for response %d\n", -ENOMEM);
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return;
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}
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/*
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* The status is stored in bits 31:16 of the SERVICES_SR register.
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* It is only valid when BUSY == 0.
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* We should *never* get an interrupt while the controller is
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* still in the busy state. If we do, something has gone badly
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* wrong & the content of the mailbox would not be valid.
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*/
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if (mpfs_mbox_busy(mbox)) {
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dev_err(mbox->dev, "got an interrupt but system controller is busy\n");
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response->resp_status = 0xDEAD;
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return;
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}
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status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
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/*
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* If the status of the individual servers is non-zero, the service has
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* failed. The contents of the mailbox at this point are not be valid,
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* so don't bother reading them. Set the status so that the driver
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* implementing the service can handle the result.
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*/
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response->resp_status = (status & SCB_STATUS_MASK) >> SCB_STATUS_POS;
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if (response->resp_status)
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return;
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if (!mpfs_mbox_busy(mbox)) {
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for (i = 0; i < num_words; i++) {
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response->resp_msg[i] =
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readl_relaxed(mbox->mbox_base
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+ mbox->resp_offset + i * 0x4);
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}
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}
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mbox_chan_received_data(chan, response);
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}
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static irqreturn_t mpfs_mbox_inbox_isr(int irq, void *data)
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{
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struct mbox_chan *chan = data;
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struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
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writel_relaxed(0, mbox->int_reg);
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mpfs_mbox_rx_data(chan);
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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 int mpfs_mbox_startup(struct mbox_chan *chan)
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{
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struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
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int ret = 0;
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if (!mbox)
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return -EINVAL;
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ret = devm_request_irq(mbox->dev, mbox->irq, mpfs_mbox_inbox_isr, 0, "mpfs-mailbox", chan);
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if (ret)
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dev_err(mbox->dev, "failed to register mailbox interrupt:%d\n", ret);
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return ret;
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}
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static void mpfs_mbox_shutdown(struct mbox_chan *chan)
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{
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struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
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devm_free_irq(mbox->dev, mbox->irq, chan);
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}
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static const struct mbox_chan_ops mpfs_mbox_ops = {
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.send_data = mpfs_mbox_send_data,
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.startup = mpfs_mbox_startup,
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.shutdown = mpfs_mbox_shutdown,
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};
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static int mpfs_mbox_probe(struct platform_device *pdev)
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{
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struct mpfs_mbox *mbox;
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struct resource *regs;
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int ret;
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mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
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if (!mbox)
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return -ENOMEM;
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mbox->ctrl_base = devm_platform_get_and_ioremap_resource(pdev, 0, ®s);
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if (IS_ERR(mbox->ctrl_base))
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return PTR_ERR(mbox->ctrl_base);
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mbox->int_reg = devm_platform_get_and_ioremap_resource(pdev, 1, ®s);
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if (IS_ERR(mbox->int_reg))
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return PTR_ERR(mbox->int_reg);
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mbox->mbox_base = devm_platform_get_and_ioremap_resource(pdev, 2, ®s);
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if (IS_ERR(mbox->mbox_base)) // account for the old dt-binding w/ 2 regs
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mbox->mbox_base = mbox->ctrl_base + MAILBOX_REG_OFFSET;
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mbox->irq = platform_get_irq(pdev, 0);
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if (mbox->irq < 0)
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return mbox->irq;
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mbox->dev = &pdev->dev;
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mbox->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 = mbox->chans;
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mbox->controller.ops = &mpfs_mbox_ops;
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mbox->controller.txdone_irq = true;
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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, "Registering MPFS mailbox controller failed\n");
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return ret;
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}
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dev_info(&pdev->dev, "Registered MPFS mailbox controller driver\n");
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return 0;
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}
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static const struct of_device_id mpfs_mbox_of_match[] = {
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{.compatible = "microchip,mpfs-mailbox", },
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{},
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};
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MODULE_DEVICE_TABLE(of, mpfs_mbox_of_match);
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static struct platform_driver mpfs_mbox_driver = {
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.driver = {
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.name = "mpfs-mailbox",
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.of_match_table = mpfs_mbox_of_match,
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},
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.probe = mpfs_mbox_probe,
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};
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module_platform_driver(mpfs_mbox_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
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MODULE_DESCRIPTION("MPFS mailbox controller driver");
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