[v1,1/3] mailbox: Add support for Armada 37xx rWTM mailbox

This adds support for the mailbox via which the kernel can communicate
with the firmware running on the secure processor of the Armada 37xx
SOC.

The rWTM secure processor has access to internal eFuses and
cryptographic circuits, such as the Entropy Bit Generator to generate
true random numbers.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
---
 drivers/mailbox/Kconfig                    |  10 +
 drivers/mailbox/Makefile                   |   2 +
 drivers/mailbox/armada-37xx-rwtm-mailbox.c | 227 +++++++++++++++++++++
 3 files changed, 239 insertions(+)
 create mode 100644 drivers/mailbox/armada-37xx-rwtm-mailbox.c

Hi Marek,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.20-rc7 next-20181218]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Marek-Beh-n/mailbox-Add-support-for-Armada-37xx-rWTM-mailbox/20181218-023213
config: i386-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

>> drivers/mailbox/armada-37xx-rwtm-mailbox.c:16:10: fatal error: linux/armada-37xx-rwtm-mailbox.h: No such file or directory
    #include <linux/armada-37xx-rwtm-mailbox.h>
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   compilation terminated.

vim +16 drivers/mailbox/armada-37xx-rwtm-mailbox.c

  > 16	#include <linux/armada-37xx-rwtm-mailbox.h>
    17	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

I forgot to git add the header file containing definitions of
structures for messages :(. Will send in the next version.

On Mon, 17 Dec 2018 16:37:04 +0100
Marek Behún <marek.behun@nic.cz> wrote:

> This adds support for the mailbox via which the kernel can communicate
> with the firmware running on the secure processor of the Armada 37xx
> SOC.
> 
> The rWTM secure processor has access to internal eFuses and
> cryptographic circuits, such as the Entropy Bit Generator to generate
> true random numbers.
> 
> Signed-off-by: Marek Behún <marek.behun@nic.cz>
> ---
>  drivers/mailbox/Kconfig                    |  10 +
>  drivers/mailbox/Makefile                   |   2 +
>  drivers/mailbox/armada-37xx-rwtm-mailbox.c | 227
> +++++++++++++++++++++ 3 files changed, 239 insertions(+)
>  create mode 100644 drivers/mailbox/armada-37xx-rwtm-mailbox.c
> 
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index 3eeb12e93e98..939927290ac6 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -41,6 +41,16 @@ config PL320_MBOX
>  	  Management Engine, primarily for cpufreq. Say Y here if
> you want to use the PL320 IPCM support.
>  
> +config ARMADA_37XX_RWTM_MBOX
> +	tristate "Armada 37xx rWTM BIU Mailbox"
> +	depends on ARCH_MVEBU || COMPILE_TEST
> +	depends on OF
> +	help
> +	  Mailbox implementation for communication with the the
> firmware
> +	  running on the Cortex-M3 rWTM secure processor of the
> Armada 37xx
> +	  SOC. Say Y here if you are building for such a device (for
> example
> +	  the Turris Mox router).
> +
>  config OMAP2PLUS_MBOX
>  	tristate "OMAP2+ Mailbox framework support"
>  	depends on ARCH_OMAP2PLUS
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index c818b5d011ae..792894db6b43 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -9,6 +9,8 @@ obj-$(CONFIG_ARM_MHU)	+= arm_mhu.o
>  
>  obj-$(CONFIG_IMX_MBOX)	+= imx-mailbox.o
>  
> +obj-$(CONFIG_ARMADA_37XX_RWTM_MBOX)	+=
> armada-37xx-rwtm-mailbox.o +
>  obj-$(CONFIG_PLATFORM_MHU)	+= platform_mhu.o
>  
>  obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
> diff --git a/drivers/mailbox/armada-37xx-rwtm-mailbox.c
> b/drivers/mailbox/armada-37xx-rwtm-mailbox.c new file mode 100644
> index 000000000000..b8b3e8cd49f0
> --- /dev/null
> +++ b/drivers/mailbox/armada-37xx-rwtm-mailbox.c
> @@ -0,0 +1,227 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * rWTM BIU Mailbox driver for Armada 37xx
> + *
> + * Author: Marek Behun <marek.behun@nic.cz>
> + */
> +
> +#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>
> +#include <linux/armada-37xx-rwtm-mailbox.h>
> +
> +#define DRIVER_NAME	"armada-37xx-rwtm-mailbox"
> +
> +/* relative to rWTM BIU Mailbox Registers */
> +#define RWTM_MBOX_PARAM(i)		(0x0 + ((i) << 2))
> +#define RWTM_MBOX_COMMAND		0x40
> +#define RWTM_MBOX_RETURN_STATUS		0x80
> +#define RWTM_MBOX_STATUS(i)		(0x84 + ((i) << 2))
> +#define RWTM_MBOX_FIFO_STATUS		0xc4
> +#define FIFO_STS_RDY			0x100
> +#define FIFO_STS_CNTR_MASK		0x7
> +#define FIFO_STS_CNTR_MAX		4
> +
> +#define RWTM_HOST_INT_RESET		0xc8
> +#define RWTM_HOST_INT_MASK		0xcc
> +#define SP_CMD_COMPLETE			BIT(0)
> +#define SP_CMD_QUEUE_FULL_ACCESS	BIT(17)
> +#define SP_CMD_QUEUE_FULL		BIT(18)
> +
> +struct a37xx_mbox {
> +	struct device *dev;
> +	struct mbox_controller controller;
> +	void __iomem *base;
> +	int irq;
> +};
> +
> +static void a37xx_mbox_receive(struct mbox_chan *chan)
> +{
> +	struct a37xx_mbox *mbox = chan->con_priv;
> +	struct armada_37xx_rwtm_rx_msg rx_msg;
> +	int i;
> +
> +	rx_msg.retval = readl(mbox->base + RWTM_MBOX_RETURN_STATUS);
> +	for (i = 0; i < 16; ++i)
> +		rx_msg.status[i] = readl(mbox->base +
> RWTM_MBOX_STATUS(i)); +
> +	mbox_chan_received_data(chan, &rx_msg);
> +}
> +
> +static irqreturn_t a37xx_mbox_irq_handler(int irq, void *data)
> +{
> +	struct mbox_chan *chan = data;
> +	struct a37xx_mbox *mbox = chan->con_priv;
> +	u32 reg;
> +
> +	reg = readl(mbox->base + RWTM_HOST_INT_RESET);
> +
> +	if (reg & SP_CMD_COMPLETE)
> +		a37xx_mbox_receive(chan);
> +
> +	if (reg & (SP_CMD_QUEUE_FULL_ACCESS | SP_CMD_QUEUE_FULL))
> +		dev_err(mbox->dev, "Secure processor command queue
> full\n"); +
> +	writel(reg, mbox->base + RWTM_HOST_INT_RESET);
> +	if (reg)
> +		mbox_chan_txdone(chan, 0);
> +
> +	return reg ? IRQ_HANDLED : IRQ_NONE;
> +}
> +
> +static int a37xx_mbox_send_data(struct mbox_chan *chan, void *data)
> +{
> +	struct a37xx_mbox *mbox = chan->con_priv;
> +	struct armada_37xx_rwtm_tx_msg *msg = data;
> +	int i;
> +	u32 reg;
> +
> +	if (!data)
> +		return -EINVAL;
> +
> +	reg = readl(mbox->base + RWTM_MBOX_FIFO_STATUS);
> +	if (!(reg & FIFO_STS_RDY)) {
> +		dev_err(mbox->dev, "Secure processor not ready\n");
> +		return -EAGAIN;
> +	}
> +
> +	if ((reg & FIFO_STS_CNTR_MASK) >= FIFO_STS_CNTR_MAX) {
> +		dev_err(mbox->dev, "Secure processor command queue
> full\n");
> +		return -EBUSY;
> +	}
> +
> +	for (i = 0; i < 16; ++i)
> +		writel(msg->args[i], mbox->base +
> RWTM_MBOX_PARAM(i));
> +	writel(msg->command, mbox->base + RWTM_MBOX_COMMAND);
> +
> +	return 0;
> +}
> +
> +static int a37xx_mbox_startup(struct mbox_chan *chan)
> +{
> +	struct a37xx_mbox *mbox = chan->con_priv;
> +	u32 reg;
> +	int ret;
> +
> +	ret = devm_request_irq(mbox->dev, mbox->irq,
> a37xx_mbox_irq_handler, 0,
> +			       DRIVER_NAME, chan);
> +	if (ret < 0) {
> +		dev_err(mbox->dev, "Cannot request irq\n");
> +		return ret;
> +	}
> +
> +	/* enable IRQ generation */
> +	reg = readl(mbox->base + RWTM_HOST_INT_MASK);
> +	reg &= ~(SP_CMD_COMPLETE | SP_CMD_QUEUE_FULL_ACCESS |
> SP_CMD_QUEUE_FULL);
> +	writel(reg, mbox->base + RWTM_HOST_INT_MASK);
> +
> +	return 0;
> +}
> +
> +static void a37xx_mbox_shutdown(struct mbox_chan *chan)
> +{
> +	u32 reg;
> +	struct a37xx_mbox *mbox = chan->con_priv;
> +
> +	/* disable interrupt generation */
> +	reg = readl(mbox->base + RWTM_HOST_INT_MASK);
> +	reg |= SP_CMD_COMPLETE | SP_CMD_QUEUE_FULL_ACCESS |
> SP_CMD_QUEUE_FULL;
> +	writel(reg, mbox->base + RWTM_HOST_INT_MASK);
> +
> +	devm_free_irq(mbox->dev, mbox->irq, chan);
> +}
> +
> +static const struct mbox_chan_ops a37xx_mbox_ops = {
> +	.send_data	= a37xx_mbox_send_data,
> +	.startup	= a37xx_mbox_startup,
> +	.shutdown	= a37xx_mbox_shutdown,
> +};
> +
> +static int armada_37xx_mbox_probe(struct platform_device *pdev)
> +{
> +	struct a37xx_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->base = devm_ioremap_resource(&pdev->dev, regs);
> +	if (IS_ERR(mbox->base)) {
> +		dev_err(&pdev->dev, "ioremap failed\n");
> +		return PTR_ERR(mbox->base);
> +	}
> +
> +	mbox->irq = platform_get_irq(pdev, 0);
> +	if (mbox->irq < 0) {
> +		dev_err(&pdev->dev, "Cannot get irq\n");
> +		return mbox->irq;
> +	}
> +
> +	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 = &a37xx_mbox_ops;
> +	mbox->controller.txdone_irq = true;
> +
> +	ret = mbox_controller_register(&mbox->controller);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Could not register mailbox
> controller\n");
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, mbox);
> +	return ret;
> +}
> +
> +static int armada_37xx_mbox_remove(struct platform_device *pdev)
> +{
> +	struct a37xx_mbox *mbox = platform_get_drvdata(pdev);
> +
> +	if (!mbox)
> +		return -EINVAL;
> +
> +	mbox_controller_unregister(&mbox->controller);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id armada_37xx_mbox_match[] = {
> +	{ .compatible = "marvell,armada-37xx-rwtm-mailbox" },
> +	{ },
> +};
> +
> +MODULE_DEVICE_TABLE(of, armada_37xx_mbox_match);
> +
> +static struct platform_driver armada_37xx_mbox_driver = {
> +	.probe	= armada_37xx_mbox_probe,
> +	.remove	= armada_37xx_mbox_remove,
> +	.driver	= {
> +		.name		= DRIVER_NAME,
> +		.of_match_table	= armada_37xx_mbox_match,
> +	},
> +};
> +
> +module_platform_driver(armada_37xx_mbox_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("rWTM BIU Mailbox driver for Armada 37xx");
> +MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");