[ARM] Orion: implement power-off method for Kurobox Pro

This patch implements the communication with the microcontroller on the
Kurobox Pro and Linkstation Pro/Live boards.  This is allowing to send
the commands needed to power-off the board correctly.
Signed-off-by: Sylver Bruneau <sylver.bruneau@googlemail.com>
Acked-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

arch/arm/mach-orion5x/kurobox_pro-setup.c

@@ -13,10 +13,12 @@
 #include <linux/platform_device.h>
 #include <linux/pci.h>
 #include <linux/irq.h>
+#include <linux/delay.h>
 #include <linux/mtd/physmap.h>
 #include <linux/mtd/nand.h>
 #include <linux/mv643xx_eth.h>
 #include <linux/i2c.h>
+#include <linux/serial_reg.h>
 #include <linux/ata_platform.h>
 #include <asm/mach-types.h>
 #include <asm/gpio.h>
@@ -174,6 +176,140 @@ static struct mv_sata_platform_data kurobox_pro_sata_data = {
 	.n_ports	= 2,
 };
 
+/*****************************************************************************
+ * Kurobox Pro specific power off method via UART1-attached microcontroller
+ ****************************************************************************/
+
+#define UART1_REG(x)	(UART1_VIRT_BASE + ((UART_##x) << 2))
+
+static int kurobox_pro_miconread(unsigned char *buf, int count)
+{
+	int i;
+	int timeout;
+
+	for (i = 0; i < count; i++) {
+		timeout = 10;
+
+		while (!(readl(UART1_REG(LSR)) & UART_LSR_DR)) {
+			if (--timeout == 0)
+				break;
+			udelay(1000);
+		}
+
+		if (timeout == 0)
+			break;
+		buf[i] = readl(UART1_REG(RX));
+	}
+
+	/* return read bytes */
+	return i;
+}
+
+static int kurobox_pro_miconwrite(const unsigned char *buf, int count)
+{
+	int i = 0;
+
+	while (count--) {
+		while (!(readl(UART1_REG(LSR)) & UART_LSR_THRE))
+			barrier();
+		writel(buf[i++], UART1_REG(TX));
+	}
+
+	return 0;
+}
+
+static int kurobox_pro_miconsend(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 */
+		kurobox_pro_miconwrite(data, count);
+
+		/* send checksum */
+		kurobox_pro_miconwrite(&checksum, 1);
+
+		if (kurobox_pro_miconread(recv_buf, sizeof(recv_buf)) <= 3) {
+			printk(KERN_ERR ">%s: receive failed.\n", __func__);
+
+			/* send preamble to clear the receive buffer */
+			memset(&send_buf, 0xff, sizeof(send_buf));
+			kurobox_pro_miconwrite(send_buf, sizeof(send_buf));
+
+			/* make dummy reads */
+			mdelay(100);
+			kurobox_pro_miconread(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) {
+				printk(KERN_ERR ">%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 */
+			printk(KERN_ERR ">%s: Error : NAK or Illegal Data "
+					"Received\n", __func__);
+		}
+	} while (retry--);
+
+	/* Interval for next command */
+	mdelay(10);
+
+	return -1;
+}
+
+static void kurobox_pro_power_off(void)
+{
+	const unsigned char watchdogkill[]	= {0x01, 0x35, 0x00};
+	const unsigned char shutdownwait[]	= {0x00, 0x0c};
+	const unsigned char poweroff[]		= {0x00, 0x06};
+	/* 38400 baud divisor */
+	const unsigned divisor = ((ORION5X_TCLK + (8 * 38400)) / (16 * 38400));
+
+	pr_info("%s: triggering power-off...\n", __func__);
+
+	/* hijack uart1 and reset into sane state (38400,8n1,even parity) */
+	writel(0x83, UART1_REG(LCR));
+	writel(divisor & 0xff, UART1_REG(DLL));
+	writel((divisor >> 8) & 0xff, UART1_REG(DLM));
+	writel(0x1b, UART1_REG(LCR));
+	writel(0x00, UART1_REG(IER));
+	writel(0x07, UART1_REG(FCR));
+	writel(0x00, UART1_REG(MCR));
+
+	/* Send the commands to shutdown the Kurobox Pro */
+	kurobox_pro_miconsend(watchdogkill, sizeof(watchdogkill)) ;
+	kurobox_pro_miconsend(shutdownwait, sizeof(shutdownwait)) ;
+	kurobox_pro_miconsend(poweroff, sizeof(poweroff));
+}
+
 /*****************************************************************************
  * General Setup
  ****************************************************************************/
@@ -194,10 +330,10 @@ static struct orion5x_mpp_mode kurobox_pro_mpp_modes[] __initdata = {
 	{ 13, MPP_SATA_LED },		/* SATA 1 presence */
 	{ 14, MPP_SATA_LED },		/* SATA 0 active */
 	{ 15, MPP_SATA_LED },		/* SATA 1 active */
-	{ 16, MPP_UNUSED },
-	{ 17, MPP_UNUSED },
-	{ 18, MPP_UNUSED },
-	{ 19, MPP_UNUSED },
+	{ 16, MPP_UART },		/* UART1 RXD */
+	{ 17, MPP_UART },		/* UART1 TXD */
+	{ 18, MPP_UART },		/* UART1 CTSn */
+	{ 19, MPP_UART },		/* UART1 RTSn */
 	{ -1 },
 };
 
@@ -231,6 +367,9 @@ static void __init kurobox_pro_init(void)
 	}
 
 	i2c_register_board_info(0, &kurobox_pro_i2c_rtc, 1);
+
+	/* register Kurobox Pro specific power-off method */
+	pm_power_off = kurobox_pro_power_off;
 }
 
 #ifdef CONFIG_MACH_KUROBOX_PRO