Linux Kernels

ARM: EXYNOS: add device tree support for MCT controller driver

This change “ARM: EXYNOS: add device tree support for MCT controller driver” (commit 36ba5d5) in Linux kernel is authored by Thomas Abraham <thomas.abraham [at] linaro.org> on Sat Mar 9 16:01:52 2013 +0900.

Description of "ARM: EXYNOS: add device tree support for MCT controller driver"

The change “ARM: EXYNOS: add device tree support for MCT controller driver” introduces changes as follows.

ARM: EXYNOS: add device tree support for MCT controller driver

Allow the MCT controller base address and interrupts to be
obtained from device tree and remove unused static definitions
of these. The non-dt support for Exynos5250 is removed but
retained for Exynos4210 based platforms.

Cc: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

Linux kernel releases containing commit 36ba5d5

The Linux kernel releases containing this commit are as follows.

Linux kernel code changes from "ARM: EXYNOS: add device tree support for MCT controller driver"

There are 123 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 .../bindings/timer/samsung,exynos4210-mct.txt | 68 +++++++++++++++++++
 arch/arm/mach-exynos/include/mach/irqs.h      |  6 --
 arch/arm/mach-exynos/mct.c                    | 49 +++++++++----
 3 files changed, 105 insertions(+), 18 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
 
diff --git a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
new file mode 100644
index 000000000000..cb47bfbcaeea
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
@@ -0,0 +1,68 @@
+Samsung's Multi Core Timer (MCT)
+
+The Samsung's Multi Core Timer (MCT) module includes two main blocks, the
+global timer and CPU local timers. The global timer is a 64-bit free running
+up-counter and can generate 4 interrupts when the counter reaches one of the
+four preset counter values. The CPU local timers are 32-bit free running
+down-counters and generate an interrupt when the counter expires. There is
+one CPU local timer instantiated in MCT for every CPU in the system.
+
+Required properties:
+
+- compatible: should be "samsung,exynos4210-mct".
+  (a) "samsung,exynos4210-mct", for mct compatible with Exynos4210 mct.
+  (b) "samsung,exynos4412-mct", for mct compatible with Exynos4412 mct.
+
+- reg: base address of the mct controller and length of the address space
+  it occupies.
+
+- interrupts: the list of interrupts generated by the controller. The following
+  should be the order of the interrupts specified. The local timer interrupts
+  should be specified after the four global timer interrupts have been
+  specified.
+
+	0: Global Timer Interrupt 0
+	1: Global Timer Interrupt 1
+	2: Global Timer Interrupt 2
+	3: Global Timer Interrupt 3
+	4: Local Timer Interrupt 0
+	5: Local Timer Interrupt 1
+	6: ..
+	7: ..
+	i: Local Timer Interrupt n
+
+Example 1: In this example, the system uses only the first global timer
+	   interrupt generated by MCT and the remaining three global timer
+	   interrupts are unused. Two local timer interrupts have been
+	   specified.
+
+	mct@10050000 {
+		compatible = "samsung,exynos4210-mct";
+		reg = <0x10050000 0x800>;
+		interrupts = <0 57 0>, <0 0 0>, <0 0 0>, <0 0 0>,
+			     <0 42 0>, <0 48 0>;
+	};
+
+Example 2: In this example, the MCT global and local timer interrupts are
+	   connected to two seperate interrupt controllers. Hence, an
+	   interrupt-map is created to map the interrupts to the respective
+	   interrupt controllers.
+
+	mct@101C0000 {
+		compatible = "samsung,exynos4210-mct";
+		reg = <0x101C0000 0x800>;
+		interrupt-controller;
+		#interrups-cells = <2>;
+		interrupt-parent = <&mct_map>;
+		interrupts = <0 0>, <1 0>, <2 0>, <3 0>,
+			     <4 0>, <5 0>;
+
+		mct_map: mct-map {
+			#interrupt-cells = <2>;
+			#address-cells = <0>;
+			#size-cells = <0>;
+			interrupt-map = <0x0 0 &combiner 23 3>,
+					<0x4 0 &gic 0 120 0>,
+					<0x5 0 &gic 0 121 0>;
+		};
+	};
diff --git a/arch/arm/mach-exynos/include/mach/irqs.h b/arch/arm/mach-exynos/include/mach/irqs.h
index 1f4dc35cd4b9..c0e75d8dd737 100644
--- a/arch/arm/mach-exynos/include/mach/irqs.h
+++ b/arch/arm/mach-exynos/include/mach/irqs.h
@@ -30,8 +30,6 @@
 
 /* For EXYNOS4 and EXYNOS5 */
 
-#define EXYNOS_IRQ_MCT_LOCALTIMER	IRQ_PPI(12)
-
 #define EXYNOS_IRQ_EINT16_31		IRQ_SPI(32)
 
 /* For EXYNOS4 SoCs */
@@ -323,8 +321,6 @@
 #define EXYNOS5_IRQ_CEC			IRQ_SPI(114)
 #define EXYNOS5_IRQ_SATA		IRQ_SPI(115)
 
-#define EXYNOS5_IRQ_MCT_L0		IRQ_SPI(120)
-#define EXYNOS5_IRQ_MCT_L1		IRQ_SPI(121)
 #define EXYNOS5_IRQ_MMC44		IRQ_SPI(123)
 #define EXYNOS5_IRQ_MDMA1		IRQ_SPI(124)
 #define EXYNOS5_IRQ_FIMC_LITE0		IRQ_SPI(125)
@@ -419,8 +415,6 @@
 #define EXYNOS5_IRQ_PMU_CPU1		COMBINER_IRQ(22, 4)
 
 #define EXYNOS5_IRQ_EINT0		COMBINER_IRQ(23, 0)
-#define EXYNOS5_IRQ_MCT_G0		COMBINER_IRQ(23, 3)
-#define EXYNOS5_IRQ_MCT_G1		COMBINER_IRQ(23, 4)
 
 #define EXYNOS5_IRQ_EINT1		COMBINER_IRQ(24, 0)
 #define EXYNOS5_IRQ_SYSMMU_LITE1_0	COMBINER_IRQ(24, 1)
diff --git a/arch/arm/mach-exynos/mct.c b/arch/arm/mach-exynos/mct.c
index 1061db4118aa..f34c933314f3 100644
--- a/arch/arm/mach-exynos/mct.c
+++ b/arch/arm/mach-exynos/mct.c
@@ -20,6 +20,8 @@
 #include <linux/delay.h>
 #include <linux/percpu.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
 
 #include <asm/arch_timer.h>
 #include <asm/localtimer.h>
@@ -474,14 +476,16 @@ static struct local_timer_ops exynos4_mct_tick_ops __cpuinitdata = {
 };
 #endif /* CONFIG_LOCAL_TIMERS */
 
-static void __init exynos4_timer_resources(void)
+static void __init exynos4_timer_resources(struct device_node *np)
 {
 	struct clk *mct_clk;
 	mct_clk = clk_get(NULL, "xtal");
 
 	clk_rate = clk_get_rate(mct_clk);
 
-	reg_base = S5P_VA_SYSTIMER;
+	reg_base = np ? of_iomap(np, 0) : S5P_VA_SYSTIMER;
+	if (!reg_base)
+		panic("%s: unable to ioremap mct address space\n", __func__);
 
 #ifdef CONFIG_LOCAL_TIMERS
 	if (mct_int_type == MCT_INT_PPI) {
@@ -498,30 +502,51 @@ static void __init exynos4_timer_resources(void)
 #endif /* CONFIG_LOCAL_TIMERS */
 }
 
+static const struct of_device_id exynos_mct_ids[] = {
+	{ .compatible = "samsung,exynos4210-mct", .data = (void *)MCT_INT_SPI },
+	{ .compatible = "samsung,exynos4412-mct", .data = (void *)MCT_INT_PPI },
+};
+
 void __init exynos4_timer_init(void)
 {
+	struct device_node *np = NULL;
+	const struct of_device_id *match;
+	u32 nr_irqs, i;
+
 	if (soc_is_exynos5440()) {
 		arch_timer_of_register();
 		return;
 	}
 
-	if (soc_is_exynos4210()) {
+#ifdef CONFIG_OF
+	np = of_find_matching_node_and_match(NULL, exynos_mct_ids, &match);
+#endif
+	if (np) {
+		mct_int_type = (u32)(match->data);
+
+		/* This driver uses only one global timer interrupt */
+		mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
+
+		/*
+		 * Find out the number of local irqs specified. The local
+		 * timer irqs are specified after the four global timer
+		 * irqs are specified.
+		 */
+#ifdef CONFIG_OF
+		nr_irqs = of_irq_count(np);
+#endif
+		for (i = MCT_L0_IRQ; i < nr_irqs; i++)
+			mct_irqs[i] = irq_of_parse_and_map(np, i);
+	} else if (soc_is_exynos4210()) {
 		mct_irqs[MCT_G0_IRQ] = EXYNOS4_IRQ_MCT_G0;
 		mct_irqs[MCT_L0_IRQ] = EXYNOS4_IRQ_MCT_L0;
 		mct_irqs[MCT_L1_IRQ] = EXYNOS4_IRQ_MCT_L1;
 		mct_int_type = MCT_INT_SPI;
-	} else if (soc_is_exynos5250()) {
-		mct_irqs[MCT_G0_IRQ] = EXYNOS5_IRQ_MCT_G0;
-		mct_irqs[MCT_L0_IRQ] = EXYNOS5_IRQ_MCT_L0;
-		mct_irqs[MCT_L1_IRQ] = EXYNOS5_IRQ_MCT_L1;
-		mct_int_type = MCT_INT_SPI;
 	} else {
-		mct_irqs[MCT_G0_IRQ] = EXYNOS4_IRQ_MCT_G0;
-		mct_irqs[MCT_L0_IRQ] = EXYNOS_IRQ_MCT_LOCALTIMER;
-		mct_int_type = MCT_INT_PPI;
+		panic("unable to determine mct controller type\n");
 	}
 
-	exynos4_timer_resources();
+	exynos4_timer_resources(np);
 	exynos4_clocksource_init();
 	exynos4_clockevent_init();
 }

The commit for this change in Linux stable tree is 36ba5d5 (patch).

Last modified: 2020/01/11 09:38