--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 Pengutronix, Oleksij Rempel <o.rempel@pengutronix.de>
+ */
+
+#include <linux/clk.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_device.h>
+#include <linux/slab.h>
+
+/* Transmit Register */
+#define IMX_MU_xTRn(x) (0x00 + 4 * (x))
+/* Receive Register */
+#define IMX_MU_xRRn(x) (0x10 + 4 * (x))
+/* Status Register */
+#define IMX_MU_xSR 0x20
+#define IMX_MU_xSR_GIPn(x) BIT(28 + (3 - (x)))
+#define IMX_MU_xSR_RFn(x) BIT(24 + (3 - (x)))
+#define IMX_MU_xSR_TEn(x) BIT(20 + (3 - (x)))
+#define IMX_MU_xSR_BRDIP BIT(9)
+
+/* Control Register */
+#define IMX_MU_xCR 0x24
+/* General Purpose Interrupt Enable */
+#define IMX_MU_xCR_GIEn(x) BIT(28 + (3 - (x)))
+/* Receive Interrupt Enable */
+#define IMX_MU_xCR_RIEn(x) BIT(24 + (3 - (x)))
+/* Transmit Interrupt Enable */
+#define IMX_MU_xCR_TIEn(x) BIT(20 + (3 - (x)))
+/* General Purpose Interrupt Request */
+#define IMX_MU_xCR_GIRn(x) BIT(16 + (3 - (x)))
+
+#define IMX_MU_CHANS 16
+#define IMX_MU_CHAN_NAME_SIZE 20
+
+enum imx_mu_chan_type {
+ IMX_MU_TYPE_TX, /* Tx */
+ IMX_MU_TYPE_RX, /* Rx */
+ IMX_MU_TYPE_TXDB, /* Tx doorbell */
+ IMX_MU_TYPE_RXDB, /* Rx doorbell */
+};
+
+struct imx_mu_con_priv {
+ unsigned int idx;
+ char irq_desc[IMX_MU_CHAN_NAME_SIZE];
+ enum imx_mu_chan_type type;
+ struct mbox_chan *chan;
+ struct tasklet_struct txdb_tasklet;
+};
+
+struct imx_mu_priv {
+ struct device *dev;
+ void __iomem *base;
+ spinlock_t xcr_lock; /* control register lock */
+
+ struct mbox_controller mbox;
+ struct mbox_chan mbox_chans[IMX_MU_CHANS];
+
+ struct imx_mu_con_priv con_priv[IMX_MU_CHANS];
+ struct clk *clk;
+ int irq;
+
+ bool side_b;
+};
+
+static struct imx_mu_priv *to_imx_mu_priv(struct mbox_controller *mbox)
+{
+ return container_of(mbox, struct imx_mu_priv, mbox);
+}
+
+static void imx_mu_write(struct imx_mu_priv *priv, u32 val, u32 offs)
+{
+ iowrite32(val, priv->base + offs);
+}
+
+static u32 imx_mu_read(struct imx_mu_priv *priv, u32 offs)
+{
+ return ioread32(priv->base + offs);
+}
+
+static u32 imx_mu_xcr_rmw(struct imx_mu_priv *priv, u32 set, u32 clr)
+{
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&priv->xcr_lock, flags);
+ val = imx_mu_read(priv, IMX_MU_xCR);
+ val &= ~clr;
+ val |= set;
+ imx_mu_write(priv, val, IMX_MU_xCR);
+ spin_unlock_irqrestore(&priv->xcr_lock, flags);
+
+ return val;
+}
+
+static void imx_mu_txdb_tasklet(unsigned long data)
+{
+ struct imx_mu_con_priv *cp = (struct imx_mu_con_priv *)data;
+
+ mbox_chan_txdone(cp->chan, 0);
+}
+
+static irqreturn_t imx_mu_isr(int irq, void *p)
+{
+ struct mbox_chan *chan = p;
+ struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+ struct imx_mu_con_priv *cp = chan->con_priv;
+ u32 val, ctrl, dat;
+
+ ctrl = imx_mu_read(priv, IMX_MU_xCR);
+ val = imx_mu_read(priv, IMX_MU_xSR);
+
+ switch (cp->type) {
+ case IMX_MU_TYPE_TX:
+ val &= IMX_MU_xSR_TEn(cp->idx) &
+ (ctrl & IMX_MU_xCR_TIEn(cp->idx));
+ break;
+ case IMX_MU_TYPE_RX:
+ val &= IMX_MU_xSR_RFn(cp->idx) &
+ (ctrl & IMX_MU_xCR_RIEn(cp->idx));
+ break;
+ case IMX_MU_TYPE_RXDB:
+ val &= IMX_MU_xSR_GIPn(cp->idx) &
+ (ctrl & IMX_MU_xCR_GIEn(cp->idx));
+ break;
+ default:
+ break;
+ }
+
+ if (!val)
+ return IRQ_NONE;
+
+ if (val == IMX_MU_xSR_TEn(cp->idx)) {
+ imx_mu_xcr_rmw(priv, 0, IMX_MU_xCR_TIEn(cp->idx));
+ mbox_chan_txdone(chan, 0);
+ } else if (val == IMX_MU_xSR_RFn(cp->idx)) {
+ dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
+ mbox_chan_received_data(chan, (void *)&dat);
+ } else if (val == IMX_MU_xSR_GIPn(cp->idx)) {
+ imx_mu_write(priv, IMX_MU_xSR_GIPn(cp->idx), IMX_MU_xSR);
+ mbox_chan_received_data(chan, NULL);
+ } else {
+ dev_warn_ratelimited(priv->dev, "Not handled interrupt\n");
+ return IRQ_NONE;
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int imx_mu_send_data(struct mbox_chan *chan, void *data)
+{
+ struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+ struct imx_mu_con_priv *cp = chan->con_priv;
+ u32 *arg = data;
+
+ switch (cp->type) {
+ case IMX_MU_TYPE_TX:
+ imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
+ imx_mu_xcr_rmw(priv, IMX_MU_xCR_TIEn(cp->idx), 0);
+ break;
+ case IMX_MU_TYPE_TXDB:
+ imx_mu_xcr_rmw(priv, IMX_MU_xCR_GIRn(cp->idx), 0);
+ tasklet_schedule(&cp->txdb_tasklet);
+ break;
+ default:
+ dev_warn_ratelimited(priv->dev, "Send data on wrong channel type: %d\n", cp->type);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int imx_mu_startup(struct mbox_chan *chan)
+{
+ struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+ struct imx_mu_con_priv *cp = chan->con_priv;
+ int ret;
+
+ if (cp->type == IMX_MU_TYPE_TXDB) {
+ /* Tx doorbell don't have ACK support */
+ tasklet_init(&cp->txdb_tasklet, imx_mu_txdb_tasklet,
+ (unsigned long)cp);
+ return 0;
+ }
+
+ ret = request_irq(priv->irq, imx_mu_isr, IRQF_SHARED, cp->irq_desc,
+ chan);
+ if (ret) {
+ dev_err(priv->dev,
+ "Unable to acquire IRQ %d\n", priv->irq);
+ return ret;
+ }
+
+ switch (cp->type) {
+ case IMX_MU_TYPE_RX:
+ imx_mu_xcr_rmw(priv, IMX_MU_xCR_RIEn(cp->idx), 0);
+ break;
+ case IMX_MU_TYPE_RXDB:
+ imx_mu_xcr_rmw(priv, IMX_MU_xCR_GIEn(cp->idx), 0);
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+static void imx_mu_shutdown(struct mbox_chan *chan)
+{
+ struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+ struct imx_mu_con_priv *cp = chan->con_priv;
+
+ if (cp->type == IMX_MU_TYPE_TXDB)
+ tasklet_kill(&cp->txdb_tasklet);
+
+ imx_mu_xcr_rmw(priv, 0,
+ IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));
+
+ free_irq(priv->irq, chan);
+}
+
+static const struct mbox_chan_ops imx_mu_ops = {
+ .send_data = imx_mu_send_data,
+ .startup = imx_mu_startup,
+ .shutdown = imx_mu_shutdown,
+};
+
+static struct mbox_chan * imx_mu_xlate(struct mbox_controller *mbox,
+ const struct of_phandle_args *sp)
+{
+ u32 type, idx, chan;
+
+ if (sp->args_count != 2) {
+ dev_err(mbox->dev, "Invalid argument count %d\n", sp->args_count);
+ return ERR_PTR(-EINVAL);
+ }
+
+ type = sp->args[0]; /* channel type */
+ idx = sp->args[1]; /* index */
+ chan = type * 4 + idx;
+
+ if (chan >= mbox->num_chans) {
+ dev_err(mbox->dev, "Not supported channel number: %d. (type: %d, idx: %d)\n", chan, type, idx);
+ return ERR_PTR(-EINVAL);
+ }
+
+ return &mbox->chans[chan];
+}
+
+static void imx_mu_init_generic(struct imx_mu_priv *priv)
+{
+ if (priv->side_b)
+ return;
+
+ /* Set default MU configuration */
+ imx_mu_write(priv, 0, IMX_MU_xCR);
+}
+
+static int imx_mu_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct resource *iomem;
+ struct imx_mu_priv *priv;
+ unsigned int i;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = dev;
+
+ iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->base = devm_ioremap_resource(&pdev->dev, iomem);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->irq = platform_get_irq(pdev, 0);
+ if (priv->irq < 0)
+ return priv->irq;
+
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk)) {
+ if (PTR_ERR(priv->clk) != -ENOENT)
+ return PTR_ERR(priv->clk);
+
+ priv->clk = NULL;
+ }
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret) {
+ dev_err(dev, "Failed to enable clock\n");
+ return ret;
+ }
+
+ for (i = 0; i < IMX_MU_CHANS; i++) {
+ struct imx_mu_con_priv *cp = &priv->con_priv[i];
+
+ cp->idx = i % 4;
+ cp->type = i >> 2;
+ cp->chan = &priv->mbox_chans[i];
+ priv->mbox_chans[i].con_priv = cp;
+ snprintf(cp->irq_desc, sizeof(cp->irq_desc),
+ "imx_mu_chan[%i-%i]", cp->type, cp->idx);
+ }
+
+ priv->side_b = of_property_read_bool(np, "fsl,mu-side-b");
+
+ spin_lock_init(&priv->xcr_lock);
+
+ priv->mbox.dev = dev;
+ priv->mbox.ops = &imx_mu_ops;
+ priv->mbox.chans = priv->mbox_chans;
+ priv->mbox.num_chans = IMX_MU_CHANS;
+ priv->mbox.of_xlate = imx_mu_xlate;
+ priv->mbox.txdone_irq = true;
+
+ platform_set_drvdata(pdev, priv);
+
+ imx_mu_init_generic(priv);
+
+ return mbox_controller_register(&priv->mbox);
+}
+
+static int imx_mu_remove(struct platform_device *pdev)
+{
+ struct imx_mu_priv *priv = platform_get_drvdata(pdev);
+
+ mbox_controller_unregister(&priv->mbox);
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static const struct of_device_id imx_mu_dt_ids[] = {
+ { .compatible = "fsl,imx6sx-mu" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, imx_mu_dt_ids);
+
+static struct platform_driver imx_mu_driver = {
+ .probe = imx_mu_probe,
+ .remove = imx_mu_remove,
+ .driver = {
+ .name = "imx_mu",
+ .of_match_table = imx_mu_dt_ids,
+ },
+};
+module_platform_driver(imx_mu_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
+MODULE_DESCRIPTION("Message Unit driver for i.MX");
+MODULE_LICENSE("GPL v2");
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