ARM: BCM5301X: Implement SMP support
diff mbox

Message ID 1424385148-15026-1-git-send-email-zajec5@gmail.com
State New
Headers show

Commit Message

Rafał Miłecki Feb. 19, 2015, 10:32 p.m. UTC
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
 Documentation/devicetree/bindings/arm/bcm4708.txt |  17 +++
 Documentation/devicetree/bindings/arm/cpus.txt    |   1 +
 arch/arm/boot/dts/bcm4708.dtsi                    |   5 +
 arch/arm/mach-bcm/Makefile                        |   3 +
 arch/arm/mach-bcm/bcm5301x_headsmp.S              |  46 +++++++
 arch/arm/mach-bcm/bcm5301x_smp.c                  | 160 ++++++++++++++++++++++
 6 files changed, 232 insertions(+)
 create mode 100644 arch/arm/mach-bcm/bcm5301x_headsmp.S
 create mode 100644 arch/arm/mach-bcm/bcm5301x_smp.c

Comments

Rafał Miłecki March 11, 2015, 9:23 p.m. UTC | #1
On 19 February 2015 at 23:32, Rafał Miłecki <zajec5@gmail.com> wrote:
> Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

So does it look good enough to send it in pull request? :)
Florian Fainelli March 16, 2015, 4:52 p.m. UTC | #2
On 19/02/15 14:32, Rafał Miłecki wrote:
> Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
> ---

[snip]

> +Optional sub-node properties:
> +
> +compatible = "brcm,bcm4708-sysram" SYSRAM for SMP bringup.
> +		SMP-capable SoCs use part of the SYSRAM for storing
> +		location of code to be executed by the extra cores.

Is this a regular kind of SRAM? If so, can you use "mmio-sram" as a
compatible fallback?

[snip]

> +
> +	/*
> +	 * In case L1 cache has unpredictable contents at power-up
> +	 * clean its contents without flushing.
> +	 */
> +	/* bl	v7_l1_cache_invalidate */

You can remove that comment now

> +	bl      v7_invalidate_l1
> +
> +	mov	r0,#0
> +	mcr	p15,0,r0,c7,c5,0	/* Invalidate icache */

For consistency with the previous lines, you would want to space operands.

> +	dsb
> +	isb
> +
> +	/*
> +	 * we've been released from the holding pen: secondary_stack
> +	 * should now contain the SVC stack for this core
> +	 */
> +	b	secondary_startup
> +ENDPROC(bcm5301x_secondary_startup)
> +
> +	.align 2
> +1:	.long	.
> +	.long	pen_release
> diff --git a/arch/arm/mach-bcm/bcm5301x_smp.c b/arch/arm/mach-bcm/bcm5301x_smp.c
> new file mode 100644
> index 0000000..903cc0d
> --- /dev/null
> +++ b/arch/arm/mach-bcm/bcm5301x_smp.c
> @@ -0,0 +1,160 @@
> +/*
> + * Broadcom BCM470X / BCM5301X ARM platform code.
> + *
> + * Copyright (C) 2002 ARM Ltd.
> + * Copyright (C) 2015 Rafał Miłecki <zajec5@gmail.com>
> + *
> + * Licensed under the GNU/GPL. See COPYING for details.
> + */
> +
> +#include <asm/cacheflush.h>
> +#include <asm/delay.h>
> +#include <asm/smp_plat.h>
> +#include <asm/smp_scu.h>
> +
> +#include <linux/clockchips.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +
> +#define SOC_ROM_LUT_OFF		0x400
> +
> +extern void bcm5301x_secondary_startup(void);
> +
> +static void __cpuinit write_pen_release(int val)
> +{
> +	pen_release = val;
> +	smp_wmb();
> +	sync_cache_w(&pen_release);
> +}
> +
> +static DEFINE_SPINLOCK(boot_lock);
> +
> +static void __init bcm5301x_smp_secondary_set_entry(void (*entry_point)(void))
> +{
> +	void __iomem *sysram_base_addr = NULL;
> +	struct device_node *node;
> +
> +	for_each_compatible_node(node, NULL, "brcm,bcm4708-sysram") {
> +		if (!of_device_is_available(node))
> +			continue;
> +		sysram_base_addr = of_iomap(node, 0);
> +		break;
> +	}

How about of_find_compatible()? Do you expect more than one sysram node
in a DTS?

Patch
diff mbox

diff --git a/Documentation/devicetree/bindings/arm/bcm4708.txt b/Documentation/devicetree/bindings/arm/bcm4708.txt
index 6b0f49f..be5abc0 100644
--- a/Documentation/devicetree/bindings/arm/bcm4708.txt
+++ b/Documentation/devicetree/bindings/arm/bcm4708.txt
@@ -6,3 +6,20 @@  Boards with the BCM4708 SoC shall have the following properties:
 Required root node property:
 
 compatible = "brcm,bcm4708";
+
+Optional sub-node properties:
+
+compatible = "brcm,bcm4708-sysram" SYSRAM for SMP bringup.
+		SMP-capable SoCs use part of the SYSRAM for storing
+		location of code to be executed by the extra cores.
+
+Example:
+
+	{
+		compatible = "brcm,bcm4708";
+
+		smp-sysram {
+			compatible = "brcm,bcm4708-sysram";
+			reg = <0xffff0000 0x1000>;
+		};
+	};
diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
index b2aacbe..abeba52 100644
--- a/Documentation/devicetree/bindings/arm/cpus.txt
+++ b/Documentation/devicetree/bindings/arm/cpus.txt
@@ -188,6 +188,7 @@  nodes to be present and contain the properties described below.
 			  can be one of:
 			    "allwinner,sun6i-a31"
 			    "arm,psci"
+			    "brcm,bcm4708-smp"
 			    "brcm,brahma-b15"
 			    "marvell,armada-375-smp"
 			    "marvell,armada-380-smp"
diff --git a/arch/arm/boot/dts/bcm4708.dtsi b/arch/arm/boot/dts/bcm4708.dtsi
index 31141e8..9cf699d 100644
--- a/arch/arm/boot/dts/bcm4708.dtsi
+++ b/arch/arm/boot/dts/bcm4708.dtsi
@@ -15,6 +15,7 @@ 
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
+		enable-method = "brcm,bcm4708-smp";
 
 		cpu@0 {
 			device_type = "cpu";
@@ -31,4 +32,8 @@ 
 		};
 	};
 
+	smp-sysram {
+		compatible = "brcm,bcm4708-sysram";
+		reg = <0xffff0000 0x1000>;
+	};
 };
diff --git a/arch/arm/mach-bcm/Makefile b/arch/arm/mach-bcm/Makefile
index 4c38674..ca12727 100644
--- a/arch/arm/mach-bcm/Makefile
+++ b/arch/arm/mach-bcm/Makefile
@@ -36,6 +36,9 @@  obj-$(CONFIG_ARCH_BCM2835)	+= board_bcm2835.o
 
 # BCM5301X
 obj-$(CONFIG_ARCH_BCM_5301X)	+= bcm_5301x.o
+ifeq ($(CONFIG_SMP),y)
+obj-$(CONFIG_ARCH_BCM_5301X)	+= bcm5301x_smp.o bcm5301x_headsmp.o
+endif
 
 # BCM63XXx
 obj-$(CONFIG_ARCH_BCM_63XX)	:= bcm63xx.o
diff --git a/arch/arm/mach-bcm/bcm5301x_headsmp.S b/arch/arm/mach-bcm/bcm5301x_headsmp.S
new file mode 100644
index 0000000..162d25a
--- /dev/null
+++ b/arch/arm/mach-bcm/bcm5301x_headsmp.S
@@ -0,0 +1,46 @@ 
+/*
+ * Broadcom BCM470X / BCM5301X ARM platform code.
+ *
+ * Copyright (c) 2003 ARM Limited
+ * All Rights Reserved
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+#include <linux/linkage.h>
+
+/*
+ * BCM5301X specific entry point for secondary CPUs.
+ */
+ENTRY(bcm5301x_secondary_startup)
+	mrc	p15, 0, r0, c0, c0, 5
+	and	r0, r0, #15
+	adr	r4, 1f
+	ldmia	r4, {r5, r6}
+	sub	r4, r4, r5
+	add	r6, r6, r4
+pen:	ldr	r7, [r6]
+	cmp	r7, r0
+	bne	pen
+
+	/*
+	 * In case L1 cache has unpredictable contents at power-up
+	 * clean its contents without flushing.
+	 */
+	/* bl	v7_l1_cache_invalidate */
+	bl      v7_invalidate_l1
+
+	mov	r0,#0
+	mcr	p15,0,r0,c7,c5,0	/* Invalidate icache */
+	dsb
+	isb
+
+	/*
+	 * we've been released from the holding pen: secondary_stack
+	 * should now contain the SVC stack for this core
+	 */
+	b	secondary_startup
+ENDPROC(bcm5301x_secondary_startup)
+
+	.align 2
+1:	.long	.
+	.long	pen_release
diff --git a/arch/arm/mach-bcm/bcm5301x_smp.c b/arch/arm/mach-bcm/bcm5301x_smp.c
new file mode 100644
index 0000000..903cc0d
--- /dev/null
+++ b/arch/arm/mach-bcm/bcm5301x_smp.c
@@ -0,0 +1,160 @@ 
+/*
+ * Broadcom BCM470X / BCM5301X ARM platform code.
+ *
+ * Copyright (C) 2002 ARM Ltd.
+ * Copyright (C) 2015 Rafał Miłecki <zajec5@gmail.com>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include <asm/cacheflush.h>
+#include <asm/delay.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+#include <linux/clockchips.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define SOC_ROM_LUT_OFF		0x400
+
+extern void bcm5301x_secondary_startup(void);
+
+static void __cpuinit write_pen_release(int val)
+{
+	pen_release = val;
+	smp_wmb();
+	sync_cache_w(&pen_release);
+}
+
+static DEFINE_SPINLOCK(boot_lock);
+
+static void __init bcm5301x_smp_secondary_set_entry(void (*entry_point)(void))
+{
+	void __iomem *sysram_base_addr = NULL;
+	struct device_node *node;
+
+	for_each_compatible_node(node, NULL, "brcm,bcm4708-sysram") {
+		if (!of_device_is_available(node))
+			continue;
+		sysram_base_addr = of_iomap(node, 0);
+		break;
+	}
+
+	if (!sysram_base_addr) {
+		pr_warn("Failed to map sysram\n");
+		return;
+	}
+
+	writel(virt_to_phys(entry_point), sysram_base_addr + SOC_ROM_LUT_OFF);
+
+	dsb_sev();	/* Exit WFI */
+	mb();		/* make sure write buffer is drained */
+
+	iounmap(sysram_base_addr);
+}
+
+static void __init bcm5301x_smp_prepare_cpus(unsigned int max_cpus)
+{
+	void __iomem *scu_base;
+
+	if (!scu_a9_has_base()) {
+		pr_warn("Unknown SCU base\n");
+		return;
+	}
+
+	scu_base = ioremap((phys_addr_t)scu_a9_get_base(), SZ_256);
+	if (!scu_base) {
+		pr_err("Failed to remap SCU\n");
+		return;
+	}
+
+	/* Initialise the SCU */
+	scu_enable(scu_base);
+
+	/* Let CPUs know where to start */
+	bcm5301x_smp_secondary_set_entry(bcm5301x_secondary_startup);
+
+	iounmap(scu_base);
+}
+
+static void __cpuinit bcm5301x_smp_secondary_init(unsigned int cpu)
+{
+	trace_hardirqs_off();
+
+	/*
+	 * let the primary processor know we're out of the
+	 * pen, then head off into the C entry point
+	 */
+	write_pen_release(-1);
+
+	/*
+	 * Synchronise with the boot thread.
+	 */
+	spin_lock(&boot_lock);
+	spin_unlock(&boot_lock);
+}
+
+static int __cpuinit bcm5301x_smp_boot_secondary(unsigned int cpu,
+						 struct task_struct *idle)
+{
+	unsigned long timeout;
+
+	/*
+	 * set synchronisation state between this boot processor
+	 * and the secondary one
+	 */
+	spin_lock(&boot_lock);
+
+	/*
+	 * The secondary processor is waiting to be released from
+	 * the holding pen - release it, then wait for it to flag
+	 * that it has been released by resetting pen_release.
+	 *
+	 * Note that "pen_release" is the hardware CPU ID, whereas
+	 * "cpu" is Linux's internal ID.
+	 */
+	write_pen_release(cpu_logical_map(cpu));
+
+	 /* Send the secondary CPU SEV */
+	dsb_sev();
+
+	udelay(100);
+
+	/*
+	 * Send the secondary CPU a soft interrupt, thereby causing
+	 * the boot monitor to read the system wide flags register,
+	 * and branch to the address found there.
+	 */
+	arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+	/*
+	 * Timeout set on purpose in jiffies so that on slow processors
+	 * that must also have low HZ it will wait longer.
+	 */
+	timeout = jiffies + (HZ * 10);
+	while (time_before(jiffies, timeout)) {
+		smp_rmb();
+		if (pen_release == -1)
+			break;
+
+		udelay(10);
+	}
+
+	/*
+	 * now the secondary core is starting up let it run its
+	 * calibrations, then wait for it to finish
+	 */
+	spin_unlock(&boot_lock);
+
+	return pen_release != -1 ? -ENOSYS : 0;
+}
+
+static struct smp_operations bcm5301x_smp_ops __initdata = {
+	.smp_prepare_cpus	= bcm5301x_smp_prepare_cpus,
+	.smp_secondary_init	= bcm5301x_smp_secondary_init,
+	.smp_boot_secondary	= bcm5301x_smp_boot_secondary,
+};
+
+CPU_METHOD_OF_DECLARE(bcm5301x_smp, "brcm,bcm4708-smp",
+		      &bcm5301x_smp_ops);