| /* |
| * 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; |
| } |
| |
| 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); |
| } |
| |
| 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); |
| } |
| |
| 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); |
| } |
| |
| 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); |
| } |
| |
| 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; |
| } |
| |
| 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); |
| } |
| } |
| |
| 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)); |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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); |
| } |
| } |
| |
| static 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; |
| } |
| |
| 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; |
| } |
| |
| 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"); |