Re: [PATCH (resend)] mailbox: Add Altera mailbox driver

[Dinh Nguyen <dinh.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 12/12/14, 4:04 AM, Ley Foon Tan wrote:
> 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-EIB2kfCEclfQT0dZR+AlfA@public.gmane.org>
> ---
>  .../devicetree/bindings/mailbox/altera-mailbox.txt |  49 +++
>  drivers/mailbox/Kconfig                            |   6 +
>  drivers/mailbox/Makefile                           |   2 +
>  drivers/mailbox/mailbox-altera.c                   | 404 +++++++++++++++++++++
>  4 files changed, 461 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/altera-mailbox.txt
>  create mode 100644 drivers/mailbox/mailbox-altera.c
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/altera-mailbox.txt b/Documentation/devicetree/bindings/mailbox/altera-mailbox.txt
> new file mode 100644
> index 0000000..c261979
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/altera-mailbox.txt
> @@ -0,0 +1,49 @@
> +Altera Mailbox Driver
> +=====================
> +
> +Required properties:
> +- compatible :	"altr,mailbox-1.0".
> +- reg : 	physical base address of the mailbox and length of
> +		memory mapped region.
> +- #mbox-cells:	Common mailbox binding property to identify the number
> +		of cells required for the mailbox specifier. Should be 1.
> +
> +Optional properties:
> +- interrupt-parent :	interrupt source phandle.
> +- interrupts :		interrupt number. The interrupt specifier format
> +			depends on the interrupt controller parent.
> +
> +Example:
> +	mbox_tx: mailbox@0x100 {
> +		compatible = "altr,mailbox-1.0";
> +		reg = <0x100 0x8>;
> +		interrupt-parent = < &gic_0 >;
> +		interrupts = <5>;
> +		#mbox-cells = <1>;
> +	};
> +
> +	mbox_rx: mailbox@0x200 {
> +		compatible = "altr,mailbox-1.0";
> +		reg = <0x200 0x8>;
> +		interrupt-parent = < &gic_0 >;
> +		interrupts = <6>;
> +		#mbox-cells = <1>;
> +	};
> +
> +Mailbox client
> +===============
> +"mboxes" and the optional "mbox-names" (please see
> +Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
> +of the mboxes property should contain a phandle to the mailbox controller
> +device node and second argument is the channel index. It must be 0 (hardware
> +support only one channel).The equivalent "mbox-names" property value can be
> +used to give a name to the communication channel to be used by the client user.
> +
> +Example:
> +	mclient0: mclient0@0x400 {
> +		compatible = "client-1.0";
> +		reg = <0x400 0x10>;
> +		mbox-names = "mbox-tx", "mbox-rx";
> +		mboxes = <&mbox_tx 0>,
> +			 <&mbox_rx 0>;
> +	};
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index c04fed9..84325f2 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -45,4 +45,10 @@ config PCC
>  	  states). Select this driver if your platform implements the
>  	  PCC clients mentioned above.
>  
> +config ALTERA_MBOX
> +	tristate "Altera Mailbox"
> +	help
> +	  An implementation of the Altera Mailbox soft core. It is used
> +	  to send message between processors. Say Y here if you want to use the
> +	  Altera mailbox support.
>  endif
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index dd412c2..2e79231 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -7,3 +7,5 @@ obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
>  obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
>  
>  obj-$(CONFIG_PCC)		+= pcc.o
> +
> +obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o
> diff --git a/drivers/mailbox/mailbox-altera.c b/drivers/mailbox/mailbox-altera.c
> new file mode 100644
> index 0000000..9ed10de
> --- /dev/null
> +++ b/drivers/mailbox/mailbox-altera.c
> @@ -0,0 +1,404 @@
> +/*
> + * 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/kernel.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/mailbox_controller.h>

Alphabetize the headers.

> +
> +#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		1	/* polling interval 1ms */
> +
> +struct altera_mbox {
> +	bool is_sender;		/* 1-sender, 0-receiver */
> +	bool intr_mode;
> +	int irq;
> +	void __iomem *mbox_base;
> +	struct device *dev;
> +	struct mbox_chan chan;
> +	struct mbox_controller controller;
> +
> +	/* If the controller supports only RX polling mode */
> +	struct timer_list rxpoll_timer;
> +};
> +
> +static inline struct altera_mbox *to_altera_mbox(struct mbox_chan *chan)
> +{
> +	if (!chan)
> +		return NULL;
> +
> +	return container_of(chan, struct altera_mbox, chan);
> +}
> +
> +static inline int altera_mbox_full(struct altera_mbox *mbox)
> +{
> +	u32 status;
> +
> +	status = __raw_readl(mbox->mbox_base + MAILBOX_STS_REG);
> +	return MBOX_FULL(status);
> +}
> +
> +static inline int altera_mbox_pending(struct altera_mbox *mbox)
> +{
> +	u32 status;
> +
> +	status = __raw_readl(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 = __raw_readl(mbox->mbox_base + MAILBOX_INTMASK_REG);
> +	if (enable)
> +		mask |= INT_PENDING_MSK;
> +	else
> +		mask &= ~INT_PENDING_MSK;
> +	__raw_writel(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
> +}
> +
> +static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
> +{
> +	u32 mask;
> +
> +	mask = __raw_readl(mbox->mbox_base + MAILBOX_INTMASK_REG);
> +	if (enable)
> +		mask |= INT_SPACE_MSK;
> +	else
> +		mask &= ~INT_SPACE_MSK;
> +	__raw_writel(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
> +	__raw_writel(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
> +	reg = __raw_readl(mbox->mbox_base + MAILBOX_PTR_REG);
> +	if (reg == MBOX_MAGIC) {
> +		/* Clear to 0 */
> +		__raw_writel(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 = to_altera_mbox(chan);
> +	u32 data[2];
> +
> +	if (altera_mbox_pending(mbox)) {
> +		data[MBOX_PTR] = __raw_readl(mbox->mbox_base + MAILBOX_PTR_REG);
> +		data[MBOX_CMD] = __raw_readl(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 = 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 = 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 = to_altera_mbox(chan);
> +
> +	if (mbox->intr_mode) {
> +		ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,

Use devm_request_irq, since you didn't have and don't need use free_irq
in the shutdown function.

> +			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 = to_altera_mbox(chan);
> +
> +	if (mbox->intr_mode) {
> +		ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
> +			DRIVER_NAME, chan);

Use devm_request_irq


> +		if (unlikely(ret)) {
> +			dev_err(mbox->dev,
> +				"failed to register mailbox interrupt:%d\n",
> +				ret);
> +			return ret;
> +		}
> +		altera_mbox_rx_intmask(mbox, true);
> +	} else {
> +		/* 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 = 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 */
> +	altera_mbox_tx_intmask(mbox, true);
> +
> +	/* Pointer register must write before command register */
> +	__raw_writel(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
> +	__raw_writel(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 = to_altera_mbox(chan);
> +
> +	if (WARN_ON(!mbox))
> +		return false;

Are these checks necessary? Shouldn't the driver probe function have
already failed?

> +
> +	/* 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 = to_altera_mbox(chan);
> +
> +	if (WARN_ON(!mbox))
> +		return false;
> +
> +	return altera_mbox_pending(mbox) ? true : false;
> +}
> +
> +static int altera_mbox_startup(struct mbox_chan *chan)
> +{
> +	struct altera_mbox *mbox = 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 = to_altera_mbox(chan);
> +
> +	if (WARN_ON(!mbox))
> +		return;
> +
> +	if (mbox->intr_mode) {
> +		/* Unmask all interrupt masks */
> +		__raw_writel(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
> +		free_irq(mbox->irq, chan);
> +	} else if (!mbox->is_sender)
> +		del_timer_sync(&mbox->rxpoll_timer);

Need braces around the else as well.

> +}
> +
> +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 mbox_chan *chans[1];

It would be cleaner if you use devm_kzalloc to allocate the channel here.

> +	struct resource	*regs;
> +	int ret;
> +
> +	mbox = devm_kzalloc(&pdev->dev, sizeof(struct altera_mbox),
> +		GFP_KERNEL);
> +	if (!mbox)
> +		return -ENOMEM;
> +
> +	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!regs)
> +		return -ENXIO;
> +
> +	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] = &mbox->chan;
> +	mbox->controller.dev = mbox->dev;
> +	mbox->controller.num_chans = 1;
> +	mbox->controller.chans =  &mbox->chan;
> +	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;
> +		}

Need braces around the if as well.

> +	}
> +
> +	ret = mbox_controller_register(&mbox->controller);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Register mailbox failed\n");
> +		goto err;
> +	}
> +
> +	platform_set_drvdata(pdev, mbox);
> +	return 0;
> +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);
> +
> +	platform_set_drvdata(pdev, NULL);
> +	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,
> +		.owner	= THIS_MODULE,
> +		.of_match_table	= altera_mbox_match,
> +	},
> +};
> +
> +static int altera_mbox_init(void)
> +{
> +	return platform_driver_register(&altera_mbox_driver);
> +}
> +
> +static void altera_mbox_exit(void)
> +{
> +	platform_driver_unregister(&altera_mbox_driver);
> +}
> +
> +module_init(altera_mbox_init);
> +module_exit(altera_mbox_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Altera mailbox specific functions");
> +MODULE_AUTHOR("Ley Foon Tan <lftan-EIB2kfCEclfQT0dZR+AlfA@public.gmane.org>");
> +MODULE_ALIAS("platform:altera-mailbox");
> 

Dinh
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