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Release 4.14 drivers/mailbox/mailbox-altera.c

Directory: drivers/mailbox
/*
 * Copyright Altera Corporation (C) 2013-2014. All rights reserved
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mailbox_controller.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>


#define DRIVER_NAME	"altera-mailbox"


#define MAILBOX_CMD_REG			0x00

#define MAILBOX_PTR_REG			0x04

#define MAILBOX_STS_REG			0x08

#define MAILBOX_INTMASK_REG		0x0C


#define INT_PENDING_MSK			0x1

#define INT_SPACE_MSK			0x2


#define STS_PENDING_MSK			0x1

#define STS_FULL_MSK			0x2

#define STS_FULL_OFT			0x1


#define MBOX_PENDING(status)	(((status) & STS_PENDING_MSK))

#define MBOX_FULL(status)	(((status) & STS_FULL_MSK) >> STS_FULL_OFT)


enum altera_mbox_msg {
	
MBOX_CMD = 0,
	
MBOX_PTR,
};


#define MBOX_POLLING_MS		5	
/* polling interval 5ms */


struct altera_mbox {
	
bool is_sender;		/* 1-sender, 0-receiver */
	
bool intr_mode;
	
int irq;
	
void __iomem *mbox_base;
	
struct device *dev;
	
struct mbox_controller controller;

	/* If the controller supports only RX polling mode */
	
struct timer_list rxpoll_timer;
};


static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan) { if (!chan || !chan->con_priv) return NULL; return (struct altera_mbox *)chan->con_priv; }

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static inline int altera_mbox_full(struct altera_mbox *mbox) { u32 status; status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG); return MBOX_FULL(status); }

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static inline int altera_mbox_pending(struct altera_mbox *mbox) { u32 status; status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG); return MBOX_PENDING(status); }

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static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable) { u32 mask; mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG); if (enable) mask |= INT_PENDING_MSK; else mask &= ~INT_PENDING_MSK; writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG); }

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static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable) { u32 mask; mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG); if (enable) mask |= INT_SPACE_MSK; else mask &= ~INT_SPACE_MSK; writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG); }

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static bool altera_mbox_is_sender(struct altera_mbox *mbox) { u32 reg; /* Write a magic number to PTR register and read back this register. * This register is read-write if it is a sender. */ #define MBOX_MAGIC 0xA5A5AA55 writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG); reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG); if (reg == MBOX_MAGIC) { /* Clear to 0 */ writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG); return true; } return false; }

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static void altera_mbox_rx_data(struct mbox_chan *chan) { struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); u32 data[2]; if (altera_mbox_pending(mbox)) { data[MBOX_PTR] = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG); data[MBOX_CMD] = readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG); mbox_chan_received_data(chan, (void *)data); } }

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static void altera_mbox_poll_rx(unsigned long data) { struct mbox_chan *chan = (struct mbox_chan *)data; struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); altera_mbox_rx_data(chan); mod_timer(&mbox->rxpoll_timer, jiffies + msecs_to_jiffies(MBOX_POLLING_MS)); }

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static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p) { struct mbox_chan *chan = (struct mbox_chan *)p; struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); altera_mbox_tx_intmask(mbox, false); mbox_chan_txdone(chan, 0); return IRQ_HANDLED; }

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static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p) { struct mbox_chan *chan = (struct mbox_chan *)p; altera_mbox_rx_data(chan); return IRQ_HANDLED; }

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static int altera_mbox_startup_sender(struct mbox_chan *chan) { int ret; struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); if (mbox->intr_mode) { ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0, DRIVER_NAME, chan); if (unlikely(ret)) { dev_err(mbox->dev, "failed to register mailbox interrupt:%d\n", ret); return ret; } } return 0; }

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static int altera_mbox_startup_receiver(struct mbox_chan *chan) { int ret; struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); if (mbox->intr_mode) { ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0, DRIVER_NAME, chan); if (unlikely(ret)) { mbox->intr_mode = false; goto polling; /* use polling if failed */ } altera_mbox_rx_intmask(mbox, true); return 0; } polling: /* Setup polling timer */ setup_timer(&mbox->rxpoll_timer, altera_mbox_poll_rx, (unsigned long)chan); mod_timer(&mbox->rxpoll_timer, jiffies + msecs_to_jiffies(MBOX_POLLING_MS)); return 0; }

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static int altera_mbox_send_data(struct mbox_chan *chan, void *data) { struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); u32 *udata = (u32 *)data; if (!mbox || !data) return -EINVAL; if (!mbox->is_sender) { dev_warn(mbox->dev, "failed to send. This is receiver mailbox.\n"); return -EINVAL; } if (altera_mbox_full(mbox)) return -EBUSY; /* Enable interrupt before send */ if (mbox->intr_mode) altera_mbox_tx_intmask(mbox, true); /* Pointer register must write before command register */ writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG); writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG); return 0; }

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static bool altera_mbox_last_tx_done(struct mbox_chan *chan) { struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); /* Return false if mailbox is full */ return altera_mbox_full(mbox) ? false : true; }

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static bool altera_mbox_peek_data(struct mbox_chan *chan) { struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); return altera_mbox_pending(mbox) ? true : false; }

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static int altera_mbox_startup(struct mbox_chan *chan) { struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); int ret = 0; if (!mbox) return -EINVAL; if (mbox->is_sender) ret = altera_mbox_startup_sender(chan); else ret = altera_mbox_startup_receiver(chan); return ret; }

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static void altera_mbox_shutdown(struct mbox_chan *chan) { struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); if (mbox->intr_mode) { /* Unmask all interrupt masks */ writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG); free_irq(mbox->irq, chan); } else if (!mbox->is_sender) { del_timer_sync(&mbox->rxpoll_timer); } }

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static const struct mbox_chan_ops altera_mbox_ops = { .send_data = altera_mbox_send_data, .startup = altera_mbox_startup, .shutdown = altera_mbox_shutdown, .last_tx_done = altera_mbox_last_tx_done, .peek_data = altera_mbox_peek_data, };
static int altera_mbox_probe(struct platform_device *pdev) { struct altera_mbox *mbox; struct resource *regs; struct mbox_chan *chans; int ret; mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL); if (!mbox) return -ENOMEM; /* Allocated one channel */ chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL); if (!chans) return -ENOMEM; regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs); if (IS_ERR(mbox->mbox_base)) return PTR_ERR(mbox->mbox_base); /* Check is it a sender or receiver? */ mbox->is_sender = altera_mbox_is_sender(mbox); mbox->irq = platform_get_irq(pdev, 0); if (mbox->irq >= 0) mbox->intr_mode = true; mbox->dev = &pdev->dev; /* Hardware supports only one channel. */ chans[0].con_priv = mbox; mbox->controller.dev = mbox->dev; mbox->controller.num_chans = 1; mbox->controller.chans = chans; mbox->controller.ops = &altera_mbox_ops; if (mbox->is_sender) { if (mbox->intr_mode) { mbox->controller.txdone_irq = true; } else { mbox->controller.txdone_poll = true; mbox->controller.txpoll_period = MBOX_POLLING_MS; } } ret = mbox_controller_register(&mbox->controller); if (ret) { dev_err(&pdev->dev, "Register mailbox failed\n"); goto err; } platform_set_drvdata(pdev, mbox); err: return ret; }

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static int altera_mbox_remove(struct platform_device *pdev) { struct altera_mbox *mbox = platform_get_drvdata(pdev); if (!mbox) return -EINVAL; mbox_controller_unregister(&mbox->controller); return 0; }

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static const struct of_device_id altera_mbox_match[] = { { .compatible = "altr,mailbox-1.0" }, { /* Sentinel */ } }; MODULE_DEVICE_TABLE(of, altera_mbox_match); static struct platform_driver altera_mbox_driver = { .probe = altera_mbox_probe, .remove = altera_mbox_remove, .driver = { .name = DRIVER_NAME, .of_match_table = altera_mbox_match, }, }; module_platform_driver(altera_mbox_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Altera mailbox specific functions"); MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>"); MODULE_ALIAS("platform:altera-mailbox");

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Directory: drivers/mailbox
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