ARM: 6336/1: U8500 PRCMU driver

Add an initial driver for communicating with the Power, Reset and
Clock Management Unit (PRCMU) firmware in U8500.
This initial version supports AB8500 communication only.

Signed-off-by: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
Signed-off-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 231 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/prcmu.c b/arch/arm/mach-ux500/prcmu.c
new file mode 100644
index 00000000000..293274d1342
--- /dev/null
+++ b/arch/arm/mach-ux500/prcmu.c
@@ -0,0 +1,231 @@
+/*
+ * Copyright (C) ST Ericsson SA 2010
+ *
+ * License Terms: GNU General Public License v2
+ * Author: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
+ *
+ * U8500 PRCMU driver.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/mutex.h>
+#include <linux/completion.h>
+#include <linux/jiffies.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+
+#include <mach/hardware.h>
+#include <mach/prcmu-regs.h>
+
+#define PRCMU_TCDM_BASE __io_address(U8500_PRCMU_TCDM_BASE)
+
+#define REQ_MB5 (PRCMU_TCDM_BASE + 0xE44)
+#define ACK_MB5 (PRCMU_TCDM_BASE + 0xDF4)
+
+#define REQ_MB5_I2C_SLAVE_OP (REQ_MB5)
+#define REQ_MB5_I2C_HW_BITS (REQ_MB5 + 1)
+#define REQ_MB5_I2C_REG (REQ_MB5 + 2)
+#define REQ_MB5_I2C_VAL (REQ_MB5 + 3)
+
+#define ACK_MB5_I2C_STATUS (ACK_MB5 + 1)
+#define ACK_MB5_I2C_VAL (ACK_MB5 + 3)
+
+#define I2C_WRITE(slave) ((slave) << 1)
+#define I2C_READ(slave) (((slave) << 1) | BIT(0))
+#define I2C_STOP_EN BIT(3)
+
+enum ack_mb5_status {
+	I2C_WR_OK = 0x01,
+	I2C_RD_OK = 0x02,
+};
+
+#define MBOX_BIT BIT
+#define NUM_MBOX 8
+
+static struct {
+	struct mutex lock;
+	struct completion work;
+	bool failed;
+	struct {
+		u8 status;
+		u8 value;
+	} ack;
+} mb5_transfer;
+
+/**
+ * prcmu_abb_read() - Read register value(s) from the ABB.
+ * @slave:	The I2C slave address.
+ * @reg:	The (start) register address.
+ * @value:	The read out value(s).
+ * @size:	The number of registers to read.
+ *
+ * Reads register value(s) from the ABB.
+ * @size has to be 1 for the current firmware version.
+ */
+int prcmu_abb_read(u8 slave, u8 reg, u8 *value, u8 size)
+{
+	int r;
+
+	if (size != 1)
+		return -EINVAL;
+
+	r = mutex_lock_interruptible(&mb5_transfer.lock);
+	if (r)
+		return r;
+
+	while (readl(PRCM_MBOX_CPU_VAL) & MBOX_BIT(5))
+		cpu_relax();
+
+	writeb(I2C_READ(slave), REQ_MB5_I2C_SLAVE_OP);
+	writeb(I2C_STOP_EN, REQ_MB5_I2C_HW_BITS);
+	writeb(reg, REQ_MB5_I2C_REG);
+
+	writel(MBOX_BIT(5), PRCM_MBOX_CPU_SET);
+	if (!wait_for_completion_timeout(&mb5_transfer.work,
+			msecs_to_jiffies(500))) {
+		pr_err("prcmu: prcmu_abb_read timed out.\n");
+		r = -EIO;
+		goto unlock_and_return;
+	}
+	r = ((mb5_transfer.ack.status == I2C_RD_OK) ? 0 : -EIO);
+	if (!r)
+		*value = mb5_transfer.ack.value;
+
+unlock_and_return:
+	mutex_unlock(&mb5_transfer.lock);
+	return r;
+}
+EXPORT_SYMBOL(prcmu_abb_read);
+
+/**
+ * prcmu_abb_write() - Write register value(s) to the ABB.
+ * @slave:	The I2C slave address.
+ * @reg:	The (start) register address.
+ * @value:	The value(s) to write.
+ * @size:	The number of registers to write.
+ *
+ * Reads register value(s) from the ABB.
+ * @size has to be 1 for the current firmware version.
+ */
+int prcmu_abb_write(u8 slave, u8 reg, u8 *value, u8 size)
+{
+	int r;
+
+	if (size != 1)
+		return -EINVAL;
+
+	r = mutex_lock_interruptible(&mb5_transfer.lock);
+	if (r)
+		return r;
+
+
+	while (readl(PRCM_MBOX_CPU_VAL) & MBOX_BIT(5))
+		cpu_relax();
+
+	writeb(I2C_WRITE(slave), REQ_MB5_I2C_SLAVE_OP);
+	writeb(I2C_STOP_EN, REQ_MB5_I2C_HW_BITS);
+	writeb(reg, REQ_MB5_I2C_REG);
+	writeb(*value, REQ_MB5_I2C_VAL);
+
+	writel(MBOX_BIT(5), PRCM_MBOX_CPU_SET);
+	if (!wait_for_completion_timeout(&mb5_transfer.work,
+			msecs_to_jiffies(500))) {
+		pr_err("prcmu: prcmu_abb_write timed out.\n");
+		r = -EIO;
+		goto unlock_and_return;
+	}
+	r = ((mb5_transfer.ack.status == I2C_WR_OK) ? 0 : -EIO);
+
+unlock_and_return:
+	mutex_unlock(&mb5_transfer.lock);
+	return r;
+}
+EXPORT_SYMBOL(prcmu_abb_write);
+
+static void read_mailbox_0(void)
+{
+	writel(MBOX_BIT(0), PRCM_ARM_IT1_CLEAR);
+}
+
+static void read_mailbox_1(void)
+{
+	writel(MBOX_BIT(1), PRCM_ARM_IT1_CLEAR);
+}
+
+static void read_mailbox_2(void)
+{
+	writel(MBOX_BIT(2), PRCM_ARM_IT1_CLEAR);
+}
+
+static void read_mailbox_3(void)
+{
+	writel(MBOX_BIT(3), PRCM_ARM_IT1_CLEAR);
+}
+
+static void read_mailbox_4(void)
+{
+	writel(MBOX_BIT(4), PRCM_ARM_IT1_CLEAR);
+}
+
+static void read_mailbox_5(void)
+{
+	mb5_transfer.ack.status = readb(ACK_MB5_I2C_STATUS);
+	mb5_transfer.ack.value = readb(ACK_MB5_I2C_VAL);
+	complete(&mb5_transfer.work);
+	writel(MBOX_BIT(5), PRCM_ARM_IT1_CLEAR);
+}
+
+static void read_mailbox_6(void)
+{
+	writel(MBOX_BIT(6), PRCM_ARM_IT1_CLEAR);
+}
+
+static void read_mailbox_7(void)
+{
+	writel(MBOX_BIT(7), PRCM_ARM_IT1_CLEAR);
+}
+
+static void (* const read_mailbox[NUM_MBOX])(void) = {
+	read_mailbox_0,
+	read_mailbox_1,
+	read_mailbox_2,
+	read_mailbox_3,
+	read_mailbox_4,
+	read_mailbox_5,
+	read_mailbox_6,
+	read_mailbox_7
+};
+
+static irqreturn_t prcmu_irq_handler(int irq, void *data)
+{
+	u32 bits;
+	u8 n;
+
+	bits = (readl(PRCM_ARM_IT1_VAL) & (MBOX_BIT(NUM_MBOX) - 1));
+	if (unlikely(!bits))
+		return IRQ_NONE;
+
+	for (n = 0; bits; n++) {
+		if (bits & MBOX_BIT(n)) {
+			bits -= MBOX_BIT(n);
+			read_mailbox[n]();
+		}
+	}
+	return IRQ_HANDLED;
+}
+
+static int __init prcmu_init(void)
+{
+	mutex_init(&mb5_transfer.lock);
+	init_completion(&mb5_transfer.work);
+
+	/* Clean up the mailbox interrupts after pre-kernel code. */
+	writel((MBOX_BIT(NUM_MBOX) - 1), PRCM_ARM_IT1_CLEAR);
+
+	return request_irq(IRQ_PRCMU, prcmu_irq_handler, 0, "prcmu", NULL);
+}
+
+arch_initcall(prcmu_init);