Re: [PATCH v7 6/6] mailbox: Add support for i.MX7D messaging unit

[Lucas Stach <l.stach@pengutronix.de>]

Am Donnerstag, den 26.07.2018, 08:53 +0200 schrieb Oleksij Rempel:
> The Mailbox controller is able to send messages (up to 4 32 bit words)
> between the endpoints.
> 
> This driver was tested using the mailbox-test driver sending messages
> between the Cortex-A7 and the Cortex-M4.
> 
> > Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
> > Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

> ---
>  drivers/mailbox/Kconfig       |   6 +
>  drivers/mailbox/Makefile      |   2 +
>  drivers/mailbox/imx-mailbox.c | 276 ++++++++++++++++++++++++++++++++++
>  3 files changed, 284 insertions(+)
>  create mode 100644 drivers/mailbox/imx-mailbox.c
> 
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index a2bb27446dce..79060ddc380d 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -15,6 +15,12 @@ config ARM_MHU
> >  	  The controller has 3 mailbox channels, the last of which can be
> >  	  used in Secure mode only.
>  
> +config IMX_MBOX
> > +	tristate "i.MX Mailbox"
> > +	depends on ARCH_MXC || COMPILE_TEST
> > +	help
> > +	  Mailbox implementation for i.MX Messaging Unit (MU).
> +
>  config PLATFORM_MHU
> >  	tristate "Platform MHU Mailbox"
> >  	depends on OF
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index cc23c3a43fcd..ba2fe1b6dd62 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> > @@ -7,6 +7,8 @@ obj-$(CONFIG_MAILBOX_TEST)	+= mailbox-test.o
>  
> >  obj-$(CONFIG_ARM_MHU)	+= arm_mhu.o
>  
> > +obj-$(CONFIG_IMX_MBOX)	+= imx-mailbox.o
> +
> >  obj-$(CONFIG_PLATFORM_MHU)	+= platform_mhu.o
>  
> >  obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
> diff --git a/drivers/mailbox/imx-mailbox.c b/drivers/mailbox/imx-mailbox.c
> new file mode 100644
> index 000000000000..ecfddca5e31c
> --- /dev/null
> +++ b/drivers/mailbox/imx-mailbox.c
> @@ -0,0 +1,276 @@
> +// 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_TEn(x)	BIT(20 + (3 - (x)))
> > +#define IMX_MU_xSR_RFn(x)	BIT(24 + (3 - (x)))
> > +#define IMX_MU_xSR_BRDIP	BIT(9)
> +
> +/* Control Register */
> > +#define IMX_MU_xCR		0x24
> +/* Transmit Interrupt Enable */
> > +#define IMX_MU_xCR_TIEn(x)	BIT(20 + (3 - (x)))
> +/* Receive Interrupt Enable */
> > +#define IMX_MU_xCR_RIEn(x)	BIT(24 + (3 - (x)))
> +
> > +#define IMX_MU_CHANS	4u
> +
> +struct imx_mu_con_priv {
> > > +	int			irq;
> > > +	unsigned int		idx;
> > > +	char			*irq_desc;
> +};
> +
> +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;
> +
> > > +	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 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);
> > +	val &= IMX_MU_xSR_TEn(cp->idx) | IMX_MU_xSR_RFn(cp->idx);
> > +	val &= ctrl & (IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));
> > +	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);
> > +	}
> +
> > +	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);
> > +	}
> +
> > +	return IRQ_HANDLED;
> +}
> +
> +static bool imx_mu_last_tx_done(struct mbox_chan *chan)
> +{
> > +	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> > +	struct imx_mu_con_priv *cp = chan->con_priv;
> +
> > +	/* test if transmit register is empty */
> > +	return imx_mu_read(priv, IMX_MU_xSR) & IMX_MU_xSR_TEn(cp->idx);
> +}
> +
> +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;
> +
> > +	if (!imx_mu_last_tx_done(chan))
> > +		return -EBUSY;
> +
> > +	imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
> > +	imx_mu_xcr_rmw(priv, IMX_MU_xSR_TEn(cp->idx), 0);
> +
> > +	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;
> +
> > +	cp->irq_desc = kasprintf(GFP_KERNEL, "imx_mu_chan[%i]", cp->idx);
> > +	if (!cp->irq_desc)
> > +		return -ENOMEM;
> +
> > +	ret = request_irq(cp->irq, imx_mu_isr, IRQF_SHARED, cp->irq_desc,
> > +			  chan);
> > +	if (ret) {
> > +		dev_err(priv->dev,
> > +			"Unable to acquire IRQ %d\n", cp->irq);
> > +		return ret;
> > +	}
> +
> > +	imx_mu_xcr_rmw(priv, IMX_MU_xCR_RIEn(cp->idx), 0);
> +
> > +	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;
> +
> > +	imx_mu_xcr_rmw(priv, 0,
> > +		   IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));
> +
> > +	free_irq(cp->irq, chan);
> > +	kfree(cp->irq_desc);
> +}
> +
> +static const struct mbox_chan_ops imx_mu_ops = {
> > +	.send_data = imx_mu_send_data,
> > +	.startup = imx_mu_startup,
> > +	.shutdown = imx_mu_shutdown,
> +};
> +
> +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 irq, 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);
> +
> > +	irq = platform_get_irq(pdev, 0);
> > +	if (irq < 0)
> > +		return 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;
> > +		cp->irq = irq;
> > +		priv->mbox_chans[i].con_priv = cp;
> > +	}
> +
> > +	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.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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