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![Conor Dooley](/assets/img/avatar_default.png)
Services are supposed to generate an interrupt once completed, whether or not they have do so successfully. What appears to be a bug in the system controller means that interrupts are only generated for *successful* services. Currently, the status of a service is only checked in the mpfs_mbox_rx_data() once an interrupt is received. As it turns out, this is not really helpful where the potentially buggy behaviour is present, as we'll only see the status for successes where it is moot anyway. Jassi suggested moving the check to the .tx_done() callback instead. This makes sense, as the busy bit that tx_done() is polling will be lowered on completion, regardless of whether the service passed or failed. That allows us to check the status bits for all services, whether they generate an interrupt or not & pass something more informative than -EBADMSG back to the drivers implementing individual services. Suggested-by: Jassi Brar <jassisinghbrar@gmail.com> Acked-by: Jassi Brar <jaswinder.singh@linaro.org> Tested-by: Valentina Fernandez <valentina.fernandezalanis@microchip.com> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
286 lines
7.4 KiB
C
286 lines
7.4 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(SCB_CTRL_POS + SCB_MASK_WIDTH - 1, 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 bool mpfs_mbox_last_tx_done(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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u32 val;
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if (mpfs_mbox_busy(mbox))
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return false;
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/*
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* The service status is stored in bits 31:16 of the SERVICES_SR
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* register & is only valid when the system controller is not busy.
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* Failed services are intended to generated interrupts, but in reality
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* this does not happen, so the status must be checked here.
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*/
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val = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
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response->resp_status = (val & SCB_STATUS_MASK) >> SCB_STATUS_POS;
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return true;
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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;
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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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* 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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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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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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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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.last_tx_done = mpfs_mbox_last_tx_done,
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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_poll = true;
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mbox->controller.txpoll_period = 10u;
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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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