Subject: [PATCH 1/2] mfd: micon: Add Buffalo Kurobox Pro, Terastation II Pro/Live driver

From: [email-masked] (Lee Jones)
Date: Wed, 4 Jan 2017 11:22:27 +0000

On Wed, 28 Dec 2016, Florian Fainelli wrote:

> This driver is currently only used to reboot the devices, but the
> microcontroller hanging off UART1 on the Buffalo Kurobox Pro and
> Terastation II Pro/Live is capable of a lot more than that, which we
> will support in subsequent patches. For now, just add the reboot
> functionality to make the kernel reboot correctly.

This is not an MFD driver.  You have written a UART driver.

Please relocate it to drivers/char/tty/serial.

> Signed-off-by: Florian Fainelli <[email-masked]>
> ---
>  drivers/mfd/Kconfig                 |   8 ++
>  drivers/mfd/Makefile                |   2 +
>  drivers/mfd/micon.c                 | 204 ++++++++++++++++++++++++++++++++++++
>  include/linux/platform_data/micon.h |  10 ++
>  4 files changed, 224 insertions(+)
>  create mode 100644 drivers/mfd/micon.c
>  create mode 100644 include/linux/platform_data/micon.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 4ce3b6f11830..e7df3d29351c 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -352,6 +352,14 @@ config MFD_MX25_TSADC
>  	  i.MX25 processors. They consist of a conversion queue for general
>  	  purpose ADC and a queue for Touchscreens.
>  
> +config MFD_MICON
> +	bool "Buffalo Kurobox Pro/Terastation II Pro/Live MCU interface"
> +	depends on PLAT_ORION
> +	help
> +	  Enables support for the UART1 attached micro controller on Buffalo
> +	  Kurobox Pro and Terastation II Pro/Live NAS devices. Used for
> +	  machine restart.
> +
>  config MFD_HI6421_PMIC
>  	tristate "HiSilicon Hi6421 PMU/Codec IC"
>  	depends on OF
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index dda4d4f73ad7..61a226878129 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -94,6 +94,8 @@ obj-$(CONFIG_MFD_MC13XXX)	+= mc13xxx-core.o
>  obj-$(CONFIG_MFD_MC13XXX_SPI)	+= mc13xxx-spi.o
>  obj-$(CONFIG_MFD_MC13XXX_I2C)	+= mc13xxx-i2c.o
>  
> +obj-$(CONFIG_MFD_MICON)		+= micon.o
> +
>  obj-$(CONFIG_MFD_CORE)		+= mfd-core.o
>  
>  obj-$(CONFIG_EZX_PCAP)		+= ezx-pcap.o
> diff --git a/drivers/mfd/micon.c b/drivers/mfd/micon.c
> new file mode 100644
> index 000000000000..fe56abdc0160
> --- /dev/null
> +++ b/drivers/mfd/micon.c
> @@ -0,0 +1,204 @@
> +/*
> + * Buffalo Kurobox/Terastation Pro II specific power off method via
> + * UART1-attached microcontroller
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/io.h>
> +#include <linux/delay.h>
> +#include <linux/platform_device.h>
> +#include <linux/platform_data/micon.h>
> +#include <linux/serial_reg.h>
> +#include <linux/notifier.h>
> +#include <linux/reboot.h>
> +
> +struct micon_priv {
> +	struct device *dev;
> +	void __iomem *base;
> +	int tclk;
> +	struct notifier_block nb;
> +};
> +
> +#define UART1_REG(x)	((UART_##x) << 2)
> +
> +static int miconread(struct micon_priv *priv, unsigned char *buf, int count)
> +{
> +	int i;
> +	int timeout;
> +
> +	for (i = 0; i < count; i++) {
> +		timeout = 10;
> +
> +		while (!(readl(priv->base + UART1_REG(LSR)) & UART_LSR_DR)) {
> +			if (--timeout == 0)
> +				break;
> +			udelay(1000);
> +		}
> +
> +		if (timeout == 0)
> +			break;
> +		buf[i] = readl(priv->base + UART1_REG(RX));
> +	}
> +
> +	/* return read bytes */
> +	return i;
> +}
> +
> +static int miconwrite(struct micon_priv *priv, const unsigned char *buf,
> +			   int count)
> +{
> +	int i = 0;
> +
> +	while (count--) {
> +		while (!(readl(priv->base + UART1_REG(LSR)) & UART_LSR_THRE))
> +			barrier();
> +		writel(buf[i++], priv->base + UART1_REG(TX));
> +	}
> +
> +	return 0;
> +}
> +
> +static int miconsend(struct micon_priv *priv, const unsigned char *data,
> +			  int count)
> +{
> +	int i;
> +	unsigned char checksum = 0;
> +	unsigned char recv_buf[40];
> +	unsigned char send_buf[40];
> +	unsigned char correct_ack[3];
> +	int retry = 2;
> +
> +	/* Generate checksum */
> +	for (i = 0; i < count; i++)
> +		checksum -=  data[i];
> +
> +	do {
> +		/* Send data */
> +		miconwrite(priv, data, count);
> +
> +		/* send checksum */
> +		miconwrite(priv, &checksum, 1);
> +
> +		if (miconread(priv, recv_buf, sizeof(recv_buf)) <= 3) {
> +			dev_err(priv->dev, ">%s: receive failed.\n", __func__);
> +
> +			/* send preamble to clear the receive buffer */
> +			memset(&send_buf, 0xff, sizeof(send_buf));
> +			miconwrite(priv, send_buf, sizeof(send_buf));
> +
> +			/* make dummy reads */
> +			mdelay(100);
> +			miconread(priv, recv_buf, sizeof(recv_buf));
> +		} else {
> +			/* Generate expected ack */
> +			correct_ack[0] = 0x01;
> +			correct_ack[1] = data[1];
> +			correct_ack[2] = 0x00;
> +
> +			/* checksum Check */
> +			if ((recv_buf[0] + recv_buf[1] + recv_buf[2] +
> +			     recv_buf[3]) & 0xFF) {
> +				dev_err(priv->dev, ">%s: Checksum Error : "
> +					"Received data[%02x, %02x, %02x, %02x]"
> +					"\n", __func__, recv_buf[0],
> +					recv_buf[1], recv_buf[2], recv_buf[3]);
> +			} else {
> +				/* Check Received Data */
> +				if (correct_ack[0] == recv_buf[0] &&
> +				    correct_ack[1] == recv_buf[1] &&
> +				    correct_ack[2] == recv_buf[2]) {
> +					/* Interval for next command */
> +					mdelay(10);
> +
> +					/* Receive ACK */
> +					return 0;
> +				}
> +			}
> +			/* Received NAK or illegal Data */
> +			dev_err(priv->dev, ">%s: Error : NAK or Illegal Data "
> +					    "Received\n", __func__);
> +		}
> +	} while (retry--);
> +
> +	/* Interval for next command */
> +	mdelay(10);
> +
> +	return -1;
> +}
> +
> +static int restart_handler(struct notifier_block *this,
> +			   unsigned long code, void *cmd)
> +{
> +	struct micon_priv *priv = container_of(this, struct micon_priv, nb);
> +
> +	const unsigned char watchdogkill[]	= {0x01, 0x35, 0x00};
> +	const unsigned char shutdownwait[]	= {0x00, 0x0c};
> +	const unsigned char poweroff[]		= {0x00, 0x06};
> +	/* 38400 baud divisor */
> +	unsigned int divisor = ((priv->tclk + (8 * 38400)) / (16 * 38400));
> +
> +	if (code != SYS_DOWN && code != SYS_HALT)
> +		return NOTIFY_DONE;
> +
> +	dev_info(priv->dev, "%s: triggering power-off...\n", __func__);
> +
> +	/* hijack uart1 and reset into sane state (38400,8n1,even parity) */
> +	writel(0x83, priv->base + UART1_REG(LCR));
> +	writel(divisor & 0xff, priv->base + UART1_REG(DLL));
> +	writel((divisor >> 8) & 0xff, priv->base + UART1_REG(DLM));
> +	writel(0x1b, priv->base + UART1_REG(LCR));
> +	writel(0x00, priv->base + UART1_REG(IER));
> +	writel(0x07, priv->base + UART1_REG(FCR));
> +	writel(0x00, priv->base + UART1_REG(MCR));
> +
> +	/* Send the commands to shutdown the Terastation Pro II */
> +	miconsend(priv, watchdogkill, sizeof(watchdogkill));
> +	miconsend(priv, shutdownwait, sizeof(shutdownwait));
> +	miconsend(priv, poweroff, sizeof(poweroff));
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int micon_probe(struct platform_device *pdev)
> +{
> +	struct micon_platform_data *pdata = pdev->dev.platform_data;
> +	struct micon_priv *priv;
> +	struct resource *r;
> +	int ret;
> +
> +	if (!pdata)
> +		return -ENODEV;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = &pdev->dev;
> +	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> +	/* Don't request exclusive access since 8250 may also utilize this
> +	 * resource
> +	 */
> +	priv->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
> +	if (IS_ERR(priv->base))
> +		return -ENOMEM;
> +
> +	priv->tclk = pdata->tclk;
> +
> +	priv->nb.notifier_call = restart_handler;
> +
> +	return register_reboot_notifier(&priv->nb);
> +}
> +
> +static struct platform_driver micon_driver = {
> +	.probe	= micon_probe,
> +	.driver = {
> +		.name = MICON_NAME,
> +	},
> +};
> +builtin_platform_driver(micon_driver);
> diff --git a/include/linux/platform_data/micon.h b/include/linux/platform_data/micon.h
> new file mode 100644
> index 000000000000..67dbaad5dfaa
> --- /dev/null
> +++ b/include/linux/platform_data/micon.h
> @@ -0,0 +1,10 @@
> +#ifndef __MICON_PDATA_H
> +#define __MICON_PDATA_H
> +
> +#define MICON_NAME	"micon"
> +
> +struct micon_platform_data {
> +	int tclk;
> +};
> +
> +#endif /* __MICON_PDATA_H */

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
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