Merge tag 'rpi-for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/swarren/linux-rpi into next/soc

ARM: add basic BCM2835 SoC and Raspberry Pi board support

The BCM2835 is an ARM SoC from Broadcom. This patch adds very basic
support for this SoC; enough to boot the system into an initrd with
UART console, interrupt controller, timers, and a stub clock driver.

Also provided is a similarly basic device tree for the Raspberry Pi
Model B board.

This series was written by Simon Arlott, Chris Boot, and Dom Cobley
downstream, with reference to a Broadcom tree, and modified for upstream
and submitted by Stephen Warren.

* tag 'rpi-for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/swarren/linux-rpi:
  MAINTAINERS: add an entry for the BCM2835 ARM sub-architecture
  ARM: bcm2835: instantiate console UART
  ARM: bcm2835: add stub clock driver
  ARM: bcm2835: add system timer
  ARM: bcm2835: add interrupt controller driver
  ARM: add infra-structure for BCM2835 and Raspberry Pi

9 files changed, 450 insertions, 0 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index ece958d..36d3daa 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -152,4 +152,6 @@ source "drivers/vme/Kconfig"
 
 source "drivers/pwm/Kconfig"
 
+source "drivers/irqchip/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 5b42184..8c30e73 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -5,6 +5,8 @@
 # Rewritten to use lists instead of if-statements.
 #
 
+obj-y				+= irqchip/
+
 # GPIO must come after pinctrl as gpios may need to mux pins etc
 obj-y				+= pinctrl/
 obj-y				+= gpio/
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 5869ea3..d5c19d1 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
 obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-fixed-rate.o clk-gate.o \
 				   clk-mux.o clk-divider.o clk-fixed-factor.o
 # SoCs specific
+obj-$(CONFIG_ARCH_BCM2835)	+= clk-bcm2835.o
 obj-$(CONFIG_ARCH_NOMADIK)	+= clk-nomadik.o
 obj-$(CONFIG_ARCH_HIGHBANK)	+= clk-highbank.o
 obj-$(CONFIG_ARCH_MXS)		+= mxs/
diff --git a/drivers/clk/clk-bcm2835.c b/drivers/clk/clk-bcm2835.c
new file mode 100644
index 0000000..67ad16b
--- /dev/null
+++ b/drivers/clk/clk-bcm2835.c
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2010 Broadcom
+ * Copyright (C) 2012 Stephen Warren
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/bcm2835.h>
+
+/*
+ * These are fixed clocks. They're probably not all root clocks and it may
+ * be possible to turn them on and off but until this is mapped out better
+ * it's the only way they can be used.
+ */
+void __init bcm2835_init_clocks(void)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = clk_register_fixed_rate(NULL, "sys_pclk", NULL, CLK_IS_ROOT,
+					250000000);
+	if (!clk)
+		pr_err("sys_pclk not registered\n");
+
+	clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, CLK_IS_ROOT,
+					126000000);
+	if (!clk)
+		pr_err("apb_pclk not registered\n");
+
+	clk = clk_register_fixed_rate(NULL, "uart0_pclk", NULL, CLK_IS_ROOT,
+					3000000);
+	if (!clk)
+		pr_err("uart0_pclk not registered\n");
+	ret = clk_register_clkdev(clk, NULL, "20201000.uart");
+	if (ret)
+		pr_err("uart0_pclk alias not registered\n");
+
+	clk = clk_register_fixed_rate(NULL, "uart1_pclk", NULL, CLK_IS_ROOT,
+					125000000);
+	if (!clk)
+		pr_err("uart1_pclk not registered\n");
+	ret = clk_register_clkdev(clk, NULL, "20215000.uart");
+	if (ret)
+		pr_err("uart0_pclk alias not registered\n");
+}
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index b65d0c5..d496a55 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
 obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
 obj-$(CONFIG_CLKSRC_DBX500_PRCMU)	+= clksrc-dbx500-prcmu.o
 obj-$(CONFIG_ARMADA_370_XP_TIMER)	+= time-armada-370-xp.o
+obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835_timer.o
diff --git a/drivers/clocksource/bcm2835_timer.c b/drivers/clocksource/bcm2835_timer.c
new file mode 100644
index 0000000..bc19f12
--- /dev/null
+++ b/drivers/clocksource/bcm2835_timer.c
@@ -0,0 +1,161 @@
+/*
+ * Copyright 2012 Simon Arlott
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/bcm2835_timer.h>
+#include <linux/bitops.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include <asm/sched_clock.h>
+#include <asm/irq.h>
+
+#define REG_CONTROL	0x00
+#define REG_COUNTER_LO	0x04
+#define REG_COUNTER_HI	0x08
+#define REG_COMPARE(n)	(0x0c + (n) * 4)
+#define MAX_TIMER	3
+#define DEFAULT_TIMER	3
+
+struct bcm2835_timer {
+	void __iomem *control;
+	void __iomem *compare;
+	int match_mask;
+	struct clock_event_device evt;
+	struct irqaction act;
+};
+
+static void __iomem *system_clock __read_mostly;
+
+static u32 notrace bcm2835_sched_read(void)
+{
+	return readl_relaxed(system_clock);
+}
+
+static void bcm2835_time_set_mode(enum clock_event_mode mode,
+	struct clock_event_device *evt_dev)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_ONESHOT:
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+	default:
+		WARN(1, "%s: unhandled event mode %d\n", __func__, mode);
+		break;
+	}
+}
+
+static int bcm2835_time_set_next_event(unsigned long event,
+	struct clock_event_device *evt_dev)
+{
+	struct bcm2835_timer *timer = container_of(evt_dev,
+		struct bcm2835_timer, evt);
+	writel_relaxed(readl_relaxed(system_clock) + event,
+		timer->compare);
+	return 0;
+}
+
+static irqreturn_t bcm2835_time_interrupt(int irq, void *dev_id)
+{
+	struct bcm2835_timer *timer = dev_id;
+	void (*event_handler)(struct clock_event_device *);
+	if (readl_relaxed(timer->control) & timer->match_mask) {
+		writel_relaxed(timer->match_mask, timer->control);
+
+		event_handler = ACCESS_ONCE(timer->evt.event_handler);
+		if (event_handler)
+			event_handler(&timer->evt);
+		return IRQ_HANDLED;
+	} else {
+		return IRQ_NONE;
+	}
+}
+
+static struct of_device_id bcm2835_time_match[] __initconst = {
+	{ .compatible = "brcm,bcm2835-system-timer" },
+	{}
+};
+
+static void __init bcm2835_time_init(void)
+{
+	struct device_node *node;
+	void __iomem *base;
+	u32 freq;
+	int irq;
+	struct bcm2835_timer *timer;
+
+	node = of_find_matching_node(NULL, bcm2835_time_match);
+	if (!node)
+		panic("No bcm2835 timer node");
+
+	base = of_iomap(node, 0);
+	if (!base)
+		panic("Can't remap registers");
+
+	if (of_property_read_u32(node, "clock-frequency", &freq))
+		panic("Can't read clock-frequency");
+
+	system_clock = base + REG_COUNTER_LO;
+	setup_sched_clock(bcm2835_sched_read, 32, freq);
+
+	clocksource_mmio_init(base + REG_COUNTER_LO, node->name,
+		freq, 300, 32, clocksource_mmio_readl_up);
+
+	irq = irq_of_parse_and_map(node, DEFAULT_TIMER);
+	if (irq <= 0)
+		panic("Can't parse IRQ");
+
+	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
+	if (!timer)
+		panic("Can't allocate timer struct\n");
+
+	timer->control = base + REG_CONTROL;
+	timer->compare = base + REG_COMPARE(DEFAULT_TIMER);
+	timer->match_mask = BIT(DEFAULT_TIMER);
+	timer->evt.name = node->name;
+	timer->evt.rating = 300;
+	timer->evt.features = CLOCK_EVT_FEAT_ONESHOT;
+	timer->evt.set_mode = bcm2835_time_set_mode;
+	timer->evt.set_next_event = bcm2835_time_set_next_event;
+	timer->evt.cpumask = cpumask_of(0);
+	timer->act.name = node->name;
+	timer->act.flags = IRQF_TIMER | IRQF_SHARED;
+	timer->act.dev_id = timer;
+	timer->act.handler = bcm2835_time_interrupt;
+
+	if (setup_irq(irq, &timer->act))
+		panic("Can't set up timer IRQ\n");
+
+	clockevents_config_and_register(&timer->evt, freq, 0xf, 0xffffffff);
+
+	pr_info("bcm2835: system timer (irq = %d)\n", irq);
+}
+
+struct sys_timer bcm2835_timer = {
+	.init = bcm2835_time_init,
+};
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/drivers/irqchip/Kconfig
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
new file mode 100644
index 0000000..054321d
--- /dev/null
+++ b/drivers/irqchip/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o
diff --git a/drivers/irqchip/irq-bcm2835.c b/drivers/irqchip/irq-bcm2835.c
new file mode 100644
index 0000000..dc670cc
--- /dev/null
+++ b/drivers/irqchip/irq-bcm2835.c
@@ -0,0 +1,223 @@
+/*
+ * Copyright 2010 Broadcom
+ * Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ * Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits
+ *
+ * If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8
+ * on bank 0 is set to signify that an interrupt in bank 1 has fired, and
+ * to look in the bank 1 status register for more information.
+ *
+ * If an interrupt fires on bank 1 that _is_ in the shortcuts list, its
+ * shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1
+ * status register, but bank 0 bit 8 is _not_ set.
+ *
+ * Quirk 2: You can't mask the register 1/2 pending interrupts
+ *
+ * In a proper cascaded interrupt controller, the interrupt lines with
+ * cascaded interrupt controllers on them are just normal interrupt lines.
+ * You can mask the interrupts and get on with things. With this controller
+ * you can't do that.
+ *
+ * Quirk 3: The shortcut interrupts can't be (un)masked in bank 0
+ *
+ * Those interrupts that have shortcuts can only be masked/unmasked in
+ * their respective banks' enable/disable registers. Doing so in the bank 0
+ * enable/disable registers has no effect.
+ *
+ * The FIQ control register:
+ *  Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0)
+ *  Bit    7: Enable FIQ generation
+ *  Bits  8+: Unused
+ *
+ * An interrupt must be disabled before configuring it for FIQ generation
+ * otherwise both handlers will fire at the same time!
+ */
+
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/bcm2835.h>
+
+#include <asm/exception.h>
+
+/* Put the bank and irq (32 bits) into the hwirq */
+#define MAKE_HWIRQ(b, n)	((b << 5) | (n))
+#define HWIRQ_BANK(i)		(i >> 5)
+#define HWIRQ_BIT(i)		BIT(i & 0x1f)
+
+#define NR_IRQS_BANK0		8
+#define BANK0_HWIRQ_MASK	0xff
+/* Shortcuts can't be disabled so any unknown new ones need to be masked */
+#define SHORTCUT1_MASK		0x00007c00
+#define SHORTCUT2_MASK		0x001f8000
+#define SHORTCUT_SHIFT		10
+#define BANK1_HWIRQ		BIT(8)
+#define BANK2_HWIRQ		BIT(9)
+#define BANK0_VALID_MASK	(BANK0_HWIRQ_MASK | BANK1_HWIRQ | BANK2_HWIRQ \
+					| SHORTCUT1_MASK | SHORTCUT2_MASK)
+
+#define REG_FIQ_CONTROL		0x0c
+
+#define NR_BANKS		3
+#define IRQS_PER_BANK		32
+
+static int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
+static int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
+static int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
+static int bank_irqs[] __initconst = { 8, 32, 32 };
+
+static const int shortcuts[] = {
+	7, 9, 10, 18, 19,		/* Bank 1 */
+	21, 22, 23, 24, 25, 30		/* Bank 2 */
+};
+
+struct armctrl_ic {
+	void __iomem *base;
+	void __iomem *pending[NR_BANKS];
+	void __iomem *enable[NR_BANKS];
+	void __iomem *disable[NR_BANKS];
+	struct irq_domain *domain;
+};
+
+static struct armctrl_ic intc __read_mostly;
+
+static void armctrl_mask_irq(struct irq_data *d)
+{
+	writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
+}
+
+static void armctrl_unmask_irq(struct irq_data *d)
+{
+	writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
+}
+
+static struct irq_chip armctrl_chip = {
+	.name = "ARMCTRL-level",
+	.irq_mask = armctrl_mask_irq,
+	.irq_unmask = armctrl_unmask_irq
+};
+
+static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr,
+	const u32 *intspec, unsigned int intsize,
+	unsigned long *out_hwirq, unsigned int *out_type)
+{
+	if (WARN_ON(intsize != 2))
+		return -EINVAL;
+
+	if (WARN_ON(intspec[0] >= NR_BANKS))
+		return -EINVAL;
+
+	if (WARN_ON(intspec[1] >= IRQS_PER_BANK))
+		return -EINVAL;
+
+	if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0))
+		return -EINVAL;
+
+	*out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]);
+	*out_type = IRQ_TYPE_NONE;
+	return 0;
+}
+
+static struct irq_domain_ops armctrl_ops = {
+	.xlate = armctrl_xlate
+};
+
+static int __init armctrl_of_init(struct device_node *node,
+	struct device_node *parent)
+{
+	void __iomem *base;
+	int irq, b, i;
+
+	base = of_iomap(node, 0);
+	if (!base)
+		panic("%s: unable to map IC registers\n",
+			node->full_name);
+
+	intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
+			&armctrl_ops, NULL);
+	if (!intc.domain)
+		panic("%s: unable to create IRQ domain\n", node->full_name);
+
+	for (b = 0; b < NR_BANKS; b++) {
+		intc.pending[b] = base + reg_pending[b];
+		intc.enable[b] = base + reg_enable[b];
+		intc.disable[b] = base + reg_disable[b];
+
+		for (i = 0; i < bank_irqs[b]; i++) {
+			irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i));
+			BUG_ON(irq <= 0);
+			irq_set_chip_and_handler(irq, &armctrl_chip,
+				handle_level_irq);
+			set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+		}
+	}
+	return 0;
+}
+
+static struct of_device_id irq_of_match[] __initconst = {
+	{ .compatible = "brcm,bcm2835-armctrl-ic", .data = armctrl_of_init }
+};
+
+void __init bcm2835_init_irq(void)
+{
+	of_irq_init(irq_of_match);
+}
+
+/*
+ * Handle each interrupt across the entire interrupt controller.  This reads the
+ * status register before handling each interrupt, which is necessary given that
+ * handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
+ */
+
+static void armctrl_handle_bank(int bank, struct pt_regs *regs)
+{
+	u32 stat, irq;
+
+	while ((stat = readl_relaxed(intc.pending[bank]))) {
+		irq = MAKE_HWIRQ(bank, ffs(stat) - 1);
+		handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
+	}
+}
+
+static void armctrl_handle_shortcut(int bank, struct pt_regs *regs,
+	u32 stat)
+{
+	u32 irq = MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
+	handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
+}
+
+asmlinkage void __exception_irq_entry bcm2835_handle_irq(
+	struct pt_regs *regs)
+{
+	u32 stat, irq;
+
+	while ((stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK)) {
+		if (stat & BANK0_HWIRQ_MASK) {
+			irq = MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
+			handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
+		} else if (stat & SHORTCUT1_MASK) {
+			armctrl_handle_shortcut(1, regs, stat & SHORTCUT1_MASK);
+		} else if (stat & SHORTCUT2_MASK) {
+			armctrl_handle_shortcut(2, regs, stat & SHORTCUT2_MASK);
+		} else if (stat & BANK1_HWIRQ) {
+			armctrl_handle_bank(1, regs);
+		} else if (stat & BANK2_HWIRQ) {
+			armctrl_handle_bank(2, regs);
+		} else {
+			BUG();
+		}
+	}
+}