[PATCH v4] ARM: vexpress: add support for multiple core tiles

Will Deacon
2010-12-07T14:43:18Z

The current Versatile Express BSP defines the MACHINE_START macro
in the core tile code.

This patch moves this into the generic board code and introduces
a method for determining the current tile at runtime, allowing
the Kernel to have support for multiple tiles compiled in.
Tile-specific functions are executed via a descriptor struct containing
the correct implementations for the current tile.

Signed-off-by: Will Deacon <will.deacon@arm.com>
---

Rebased against -next and updated following discussion with Russell on
the list.

arch/arm/mach-vexpress/core.h | 5 --
arch/arm/mach-vexpress/ct-ca9x4.c | 41 ++++++++++----
arch/arm/mach-vexpress/include/mach/ct-ca9x4.h | 2 +
arch/arm/mach-vexpress/include/mach/motherboard.h | 21 +++++++
arch/arm/mach-vexpress/platsmp.c | 33 ++---------
arch/arm/mach-vexpress/v2m.c | 62 +++++++++++++++++----
6 files changed, 109 insertions(+), 55 deletions(-)

diff --git a/arch/arm/mach-vexpress/core.h b/arch/arm/mach-vexpress/core.h
index 362780d..f439715 100644
--- a/arch/arm/mach-vexpress/core.h
+++ b/arch/arm/mach-vexpress/core.h
@@ -17,8 +17,3 @@ struct amba_device name##_device = { \
.irq = IRQ_##base, \
/* .dma = DMA_##base,*/ \
}
-
-struct map_desc;
-
-void v2m_map_io(struct map_desc *tile, size_t num);
-extern struct sys_timer v2m_timer;
diff --git a/arch/arm/mach-vexpress/ct-ca9x4.c b/arch/arm/mach-vexpress/ct-ca9x4.c
index e628402..881aeca 100644
--- a/arch/arm/mach-vexpress/ct-ca9x4.c
+++ b/arch/arm/mach-vexpress/ct-ca9x4.c
@@ -10,19 +10,17 @@
#include <linux/amba/clcd.h>
#include <linux/clkdev.h>

-#include <asm/pgtable.h>
#include <asm/hardware/arm_timer.h>
#include <asm/hardware/cache-l2x0.h>
#include <asm/hardware/gic.h>
-#include <asm/mach-types.h>
#include <asm/pmu.h>
+#include <asm/smp_scu.h>
#include <asm/smp_twd.h>

#include <mach/ct-ca9x4.h>

#include <asm/hardware/timer-sp.h>

-#include <asm/mach/arch.h>
#include <asm/mach/map.h>
#include <asm/mach/time.h>

@@ -56,7 +54,7 @@ static void __init ct_ca9x4_map_io(void)
#ifdef CONFIG_LOCAL_TIMERS
twd_base = MMIO_P2V(A9_MPCORE_TWD);
#endif
- v2m_map_io(ct_ca9x4_io_desc, ARRAY_SIZE(ct_ca9x4_io_desc));
+ iotable_init(ct_ca9x4_io_desc, ARRAY_SIZE(ct_ca9x4_io_desc));
}

static void __init ct_ca9x4_init_irq(void)
@@ -242,14 +240,33 @@ static void __init ct_ca9x4_init(void)
platform_device_register(&pmu_device);
}

-MACHINE_START(VEXPRESS, "ARM-Versatile Express CA9x4")
- .boot_params = PHYS_OFFSET + 0x00000100,
+#ifdef CONFIG_SMP
+static void ct_ca9x4_init_cpu_map(void)
+{
+ int i, ncores = scu_get_core_count(MMIO_P2V(A9_MPCORE_SCU));
+
+ for (i = 0; i < ncores; ++i)
+ set_cpu_possible(i, true);
+}
+
+static void ct_ca9x4_smp_enable(unsigned int max_cpus)
+{
+ int i;
+ for (i = 0; i < max_cpus; i++)
+ set_cpu_present(i, true);
+
+ scu_enable(MMIO_P2V(A9_MPCORE_SCU));
+}
+#endif
+
+struct ct_desc ct_ca9x4_desc = {
+ .id = V2M_CT_ID_CA9,
+ .name = "CA9x4",
.map_io = ct_ca9x4_map_io,
.init_irq = ct_ca9x4_init_irq,
-#if 0
- .timer = &ct_ca9x4_timer,
-#else
- .timer = &v2m_timer,
+ .init_tile = ct_ca9x4_init,
+#ifdef CONFIG_SMP
+ .init_cpu_map = ct_ca9x4_init_cpu_map,
+ .smp_enable = ct_ca9x4_smp_enable,
#endif
- .init_machine = ct_ca9x4_init,
-MACHINE_END
+};
diff --git a/arch/arm/mach-vexpress/include/mach/ct-ca9x4.h b/arch/arm/mach-vexpress/include/mach/ct-ca9x4.h
index f9e2f8d..a34d3d4 100644
--- a/arch/arm/mach-vexpress/include/mach/ct-ca9x4.h
+++ b/arch/arm/mach-vexpress/include/mach/ct-ca9x4.h
@@ -45,4 +45,6 @@
#define IRQ_CT_CA9X4_PMU_CPU2 94
#define IRQ_CT_CA9X4_PMU_CPU3 95

+extern struct ct_desc ct_ca9x4_desc;
+
#endif
diff --git a/arch/arm/mach-vexpress/include/mach/motherboard.h b/arch/arm/mach-vexpress/include/mach/motherboard.h
index 98a8ded..aab3805 100644
--- a/arch/arm/mach-vexpress/include/mach/motherboard.h
+++ b/arch/arm/mach-vexpress/include/mach/motherboard.h
@@ -118,4 +118,25 @@
int v2m_cfg_write(u32 devfn, u32 data);
int v2m_cfg_read(u32 devfn, u32 *data);

+/*
+ * Core tile IDs
+ */
+#define V2M_CT_ID_CA9 0x0c000191
+#define V2M_CT_ID_UNSUPPORTED 0xff000191
+#define V2M_CT_ID_MASK 0xff000fff
+
+struct ct_desc {
+ u32 id;
+ const char *name;
+ void (*map_io)(void);
+ void (*init_irq)(void);
+ void (*init_tile)(void);
+#ifdef CONFIG_SMP
+ void (*init_cpu_map)(void);
+ void (*smp_enable)(unsigned int);
+#endif
+};
+
+extern struct ct_desc *ct_desc;
+
#endif
diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c
index 24f1493..9e53d89 100644
--- a/arch/arm/mach-vexpress/platsmp.c
+++ b/arch/arm/mach-vexpress/platsmp.c
@@ -17,10 +17,8 @@
#include <linux/io.h>

#include <asm/cacheflush.h>
-#include <asm/smp_scu.h>
#include <asm/unified.h>

-#include <mach/ct-ca9x4.h>
#include <mach/motherboard.h>
#define V2M_PA_CS7 0x10000000

@@ -34,11 +32,6 @@ extern void vexpress_secondary_startup(void);
*/
volatile int __cpuinitdata pen_release = -1;

-static void __iomem *scu_base_addr(void)
-{
- return MMIO_P2V(A9_MPCORE_SCU);
-}
-
static DEFINE_SPINLOCK(boot_lock);

void __cpuinit platform_secondary_init(unsigned int cpu)
@@ -115,36 +108,22 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
*/
void __init smp_init_cpus(void)
{
- void __iomem *scu_base = scu_base_addr();
- unsigned int i, ncores;
-
- ncores = scu_base ? scu_get_core_count(scu_base) : 1;
-
- /* sanity check */
- if (ncores > NR_CPUS) {
+ ct_desc->init_cpu_map();
+ if (!num_possible_cpus()) {
printk(KERN_WARNING
- "vexpress: no. of cores (%d) greater than configured "
- "maximum of %d - clipping\n",
- ncores, NR_CPUS);
- ncores = NR_CPUS;
+ "vexpress: no possible CPUs declared, forcing logical "
+ "CPU 0\n");
+ set_cpu_possible(0, true);
}
-
- for (i = 0; i < ncores; i++)
- set_cpu_possible(i, true);
}

void __init platform_smp_prepare_cpus(unsigned int max_cpus)
{
- int i;
-
/*
* Initialise the present map, which describes the set of CPUs
* actually populated@the present time.
*/
- for (i = 0; i < max_cpus; i++)
- set_cpu_present(i, true);
-
- scu_enable(scu_base_addr());
+ ct_desc->smp_enable(max_cpus);

/*
* Write the address of secondary startup into the
diff --git a/arch/arm/mach-vexpress/v2m.c b/arch/arm/mach-vexpress/v2m.c
index 314cedc..7f2de55 100644
--- a/arch/arm/mach-vexpress/v2m.c
+++ b/arch/arm/mach-vexpress/v2m.c
@@ -13,12 +13,15 @@
#include <linux/usb/isp1760.h>
#include <linux/clkdev.h>

+#include <asm/mach-types.h>
#include <asm/sizes.h>
+#include <asm/mach/arch.h>
#include <asm/mach/flash.h>
#include <asm/mach/map.h>
#include <asm/mach/time.h>
#include <asm/hardware/arm_timer.h>

+#include <mach/ct-ca9x4.h>
#include <mach/motherboard.h>

#include <asm/hardware/timer-sp.h>
@@ -40,13 +43,6 @@ static struct map_desc v2m_io_desc[] __initdata = {
},
};

-void __init v2m_map_io(struct map_desc *tile, size_t num)
-{
- iotable_init(v2m_io_desc, ARRAY_SIZE(v2m_io_desc));
- iotable_init(tile, num);
-}
-
-
static void __init v2m_timer_init(void)
{
writel(0, MMIO_P2V(V2M_TIMER0) + TIMER_CTRL);
@@ -56,7 +52,7 @@ static void __init v2m_timer_init(void)
sp804_clockevents_init(MMIO_P2V(V2M_TIMER0), IRQ_V2M_TIMER0);
}

-struct sys_timer v2m_timer = {
+static struct sys_timer v2m_timer = {
.init = v2m_timer_init,
};

@@ -342,7 +338,44 @@ static void v2m_restart(char str, const char *cmd)
printk(KERN_EMERG "Unable to reboot\n");
}

-static int __init v2m_init(void)
+struct ct_desc *ct_desc;
+
+static struct ct_desc *ct_descs[] __initdata = {
+#ifdef CONFIG_ARCH_VEXPRESS_CA9X4
+ &ct_ca9x4_desc,
+#endif
+};
+
+static void __init v2m_populate_ct_desc(void)
+{
+ int i;
+ u32 current_tile_id;
+
+ ct_desc = NULL;
+ current_tile_id = readl(MMIO_P2V(V2M_SYS_PROCID0)) & V2M_CT_ID_MASK;
+
+ for (i = 0; i < ARRAY_SIZE(ct_descs) && !ct_desc; ++i)
+ if (ct_descs[i]->id == current_tile_id)
+ ct_desc = ct_descs[i];
+
+ if (!ct_desc)
+ panic("vexpress: failed to populate core tile description "
+ "for tile ID 0x%8x\n", current_tile_id);
+}
+
+static void __init v2m_map_io(void)
+{
+ iotable_init(v2m_io_desc, ARRAY_SIZE(v2m_io_desc));
+ v2m_populate_ct_desc();
+ ct_desc->map_io();
+}
+
+static void __init v2m_init_irq(void)
+{
+ ct_desc->init_irq();
+}
+
+static void __init v2m_init(void)
{
int i;

@@ -360,6 +393,13 @@ static int __init v2m_init(void)
pm_power_off = v2m_power_off;
arm_pm_restart = v2m_restart;

- return 0;
+ ct_desc->init_tile();
}
-arch_initcall(v2m_init);
+
+MACHINE_START(VEXPRESS, "ARM-Versatile Express")
+ .boot_params = PHYS_OFFSET + 0x00000100,
+ .map_io = v2m_map_io,
+ .init_irq = v2m_init_irq,
+ .timer = &v2m_timer,
+ .init_machine = v2m_init,
+MACHINE_END
--
1.7.0.4