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authorLey Foon Tan <lftan@altera.com>2015-02-04 16:32:18 +0800
committerJassi Brar <jaswinder.singh@linaro.org>2015-02-06 10:58:27 +0530
commitf62092f6d77dfd9214ae753a24b76ba4ecd801d7 (patch)
treebbd52e987eb8151254d2bddfb8fe2e907e0f4dce /drivers/mailbox/mailbox-altera.c
parent01340df8d3cd4d8f1773d5f1f569b77bbfce31ad (diff)
mailbox: Add Altera mailbox driver
The Altera mailbox allows for interprocessor communication. It supports only one channel and work as either sender or receiver. Signed-off-by: Ley Foon Tan <lftan@altera.com>
Diffstat (limited to 'drivers/mailbox/mailbox-altera.c')
-rw-r--r--drivers/mailbox/mailbox-altera.c388
1 files changed, 388 insertions, 0 deletions
diff --git a/drivers/mailbox/mailbox-altera.c b/drivers/mailbox/mailbox-altera.c
new file mode 100644
index 000000000000..a266265677d3
--- /dev/null
+++ b/drivers/mailbox/mailbox-altera.c
@@ -0,0 +1,388 @@
+/*
+ * 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");

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