ARM: gic: allow GIC to support non-banked setups

The GIC support code is heavily using the fact that hardware
implementations are exposing banked registers. Unfortunately, it
looks like at least one GIC implementation (EXYNOS) offers both
the distributor and the CPU interfaces at different addresses,
depending on the CPU.

This problem is solved by allowing the distributor and CPU interface
addresses to be per-cpu variables for the platforms that require it.
The EXYNOS code is updated not to mess with the GIC internals while
handling interrupts, and struct gic_chip_data is back to being private.
The DT binding for the gic is updated to allow an optional "cpu-offset"
value, which is used to compute the various base addresses.

Finally, a new config option (GIC_NON_BANKED) is used to control this
feature, so the overhead is only present on kernels compiled with
support for EXYNOS.

Tested on Origen (EXYNOS4) and Panda (OMAP4).

Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/Documentation/devicetree/bindings/arm/gic.txt b/Documentation/devicetree/bindings/arm/gic.txt
index 52916b4aa1fe9b70201b2fd44f3b91893c76600b..9b4b82a721b64b5cea6309b2d81ab09c0f4f47aa 100644 (file)
--- a/Documentation/devicetree/bindings/arm/gic.txt
+++ b/Documentation/devicetree/bindings/arm/gic.txt
@@ -42,6 +42,10 @@ Optional
 - interrupts   : Interrupt source of the parent interrupt controller. Only
   present on secondary GICs.
 
+- cpu-offset   : per-cpu offset within the distributor and cpu interface
+  regions, used when the GIC doesn't have banked registers. The offset is
+  cpu-offset * cpu-nr.
+
 Example:
 
        intc: interrupt-controller@fff11000 {

diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig
index 74df9ca2be316e2df49f164df3ec680366a41a6b..a3beda1213da08ccae33fe86996371addd295d4d 100644 (file)
--- a/arch/arm/common/Kconfig
+++ b/arch/arm/common/Kconfig
@@ -2,6 +2,9 @@ config ARM_GIC
        select IRQ_DOMAIN
        bool
 
+config GIC_NON_BANKED
+       bool
+
 config ARM_VIC
        bool
 

diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 0e6ae470c94f26589c0721a059dfaded9b2f30b1..43cb6f1a7cf2e31ad364405f9217ba7a08d5c1b9 100644 (file)
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -43,6 +43,31 @@
 #include <asm/mach/irq.h>
 #include <asm/hardware/gic.h>
 
+union gic_base {
+       void __iomem *common_base;
+       void __percpu __iomem **percpu_base;
+};
+
+struct gic_chip_data {
+       unsigned int irq_offset;
+       union gic_base dist_base;
+       union gic_base cpu_base;
+#ifdef CONFIG_CPU_PM
+       u32 saved_spi_enable[DIV_ROUND_UP(1020, 32)];
+       u32 saved_spi_conf[DIV_ROUND_UP(1020, 16)];
+       u32 saved_spi_target[DIV_ROUND_UP(1020, 4)];
+       u32 __percpu *saved_ppi_enable;
+       u32 __percpu *saved_ppi_conf;
+#endif
+#ifdef CONFIG_IRQ_DOMAIN
+       struct irq_domain domain;
+#endif
+       unsigned int gic_irqs;
+#ifdef CONFIG_GIC_NON_BANKED
+       void __iomem *(*get_base)(union gic_base *);
+#endif
+};
+
 static DEFINE_RAW_SPINLOCK(irq_controller_lock);
 
 /* Address of GIC 0 CPU interface */
@@ -67,16 +92,48 @@ struct irq_chip gic_arch_extn = {
 
 static struct gic_chip_data gic_data[MAX_GIC_NR] __read_mostly;
 
+#ifdef CONFIG_GIC_NON_BANKED
+static void __iomem *gic_get_percpu_base(union gic_base *base)
+{
+       return *__this_cpu_ptr(base->percpu_base);
+}
+
+static void __iomem *gic_get_common_base(union gic_base *base)
+{
+       return base->common_base;
+}
+
+static inline void __iomem *gic_data_dist_base(struct gic_chip_data *data)
+{
+       return data->get_base(&data->dist_base);
+}
+
+static inline void __iomem *gic_data_cpu_base(struct gic_chip_data *data)
+{
+       return data->get_base(&data->cpu_base);
+}
+
+static inline void gic_set_base_accessor(struct gic_chip_data *data,
+                                        void __iomem *(*f)(union gic_base *))
+{
+       data->get_base = f;
+}
+#else
+#define gic_data_dist_base(d)  ((d)->dist_base.common_base)
+#define gic_data_cpu_base(d)   ((d)->cpu_base.common_base)
+#define gic_set_base_accessor(d,f)
+#endif
+
 static inline void __iomem *gic_dist_base(struct irq_data *d)
 {
        struct gic_chip_data *gic_data = irq_data_get_irq_chip_data(d);
-       return gic_data->dist_base;
+       return gic_data_dist_base(gic_data);
 }
 
 static inline void __iomem *gic_cpu_base(struct irq_data *d)
 {
        struct gic_chip_data *gic_data = irq_data_get_irq_chip_data(d);
-       return gic_data->cpu_base;
+       return gic_data_cpu_base(gic_data);
 }
 
 static inline unsigned int gic_irq(struct irq_data *d)
@@ -225,7 +282,7 @@ static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
        chained_irq_enter(chip, desc);
 
        raw_spin_lock(&irq_controller_lock);
-       status = readl_relaxed(chip_data->cpu_base + GIC_CPU_INTACK);
+       status = readl_relaxed(gic_data_cpu_base(chip_data) + GIC_CPU_INTACK);
        raw_spin_unlock(&irq_controller_lock);
 
        gic_irq = (status & 0x3ff);
@@ -270,7 +327,7 @@ static void __init gic_dist_init(struct gic_chip_data *gic)
        u32 cpumask;
        unsigned int gic_irqs = gic->gic_irqs;
        struct irq_domain *domain = &gic->domain;
-       void __iomem *base = gic->dist_base;
+       void __iomem *base = gic_data_dist_base(gic);
        u32 cpu = 0;
 
 #ifdef CONFIG_SMP
@@ -330,8 +387,8 @@ static void __init gic_dist_init(struct gic_chip_data *gic)
 
 static void __cpuinit gic_cpu_init(struct gic_chip_data *gic)
 {
-       void __iomem *dist_base = gic->dist_base;
-       void __iomem *base = gic->cpu_base;
+       void __iomem *dist_base = gic_data_dist_base(gic);
+       void __iomem *base = gic_data_cpu_base(gic);
        int i;
 
        /*
@@ -368,7 +425,7 @@ static void gic_dist_save(unsigned int gic_nr)
                BUG();
 
        gic_irqs = gic_data[gic_nr].gic_irqs;
-       dist_base = gic_data[gic_nr].dist_base;
+       dist_base = gic_data_dist_base(&gic_data[gic_nr]);
 
        if (!dist_base)
                return;
@@ -403,7 +460,7 @@ static void gic_dist_restore(unsigned int gic_nr)
                BUG();
 
        gic_irqs = gic_data[gic_nr].gic_irqs;
-       dist_base = gic_data[gic_nr].dist_base;
+       dist_base = gic_data_dist_base(&gic_data[gic_nr]);
 
        if (!dist_base)
                return;
@@ -439,8 +496,8 @@ static void gic_cpu_save(unsigned int gic_nr)
        if (gic_nr >= MAX_GIC_NR)
                BUG();
 
-       dist_base = gic_data[gic_nr].dist_base;
-       cpu_base = gic_data[gic_nr].cpu_base;
+       dist_base = gic_data_dist_base(&gic_data[gic_nr]);
+       cpu_base = gic_data_cpu_base(&gic_data[gic_nr]);
 
        if (!dist_base || !cpu_base)
                return;
@@ -465,8 +522,8 @@ static void gic_cpu_restore(unsigned int gic_nr)
        if (gic_nr >= MAX_GIC_NR)
                BUG();
 
-       dist_base = gic_data[gic_nr].dist_base;
-       cpu_base = gic_data[gic_nr].cpu_base;
+       dist_base = gic_data_dist_base(&gic_data[gic_nr]);
+       cpu_base = gic_data_cpu_base(&gic_data[gic_nr]);
 
        if (!dist_base || !cpu_base)
                return;
@@ -491,6 +548,11 @@ static int gic_notifier(struct notifier_block *self, unsigned long cmd,    void *v)
        int i;
 
        for (i = 0; i < MAX_GIC_NR; i++) {
+#ifdef CONFIG_GIC_NON_BANKED
+               /* Skip over unused GICs */
+               if (!gic_data[i].get_base)
+                       continue;
+#endif
                switch (cmd) {
                case CPU_PM_ENTER:
                        gic_cpu_save(i);
@@ -563,8 +625,9 @@ const struct irq_domain_ops gic_irq_domain_ops = {
 #endif
 };
 
-void __init gic_init(unsigned int gic_nr, int irq_start,
-       void __iomem *dist_base, void __iomem *cpu_base)
+void __init gic_init_bases(unsigned int gic_nr, int irq_start,
+                          void __iomem *dist_base, void __iomem *cpu_base,
+                          u32 percpu_offset)
 {
        struct gic_chip_data *gic;
        struct irq_domain *domain;
@@ -574,8 +637,36 @@ void __init gic_init(unsigned int gic_nr, int irq_start,
 
        gic = &gic_data[gic_nr];
        domain = &gic->domain;
-       gic->dist_base = dist_base;
-       gic->cpu_base = cpu_base;
+#ifdef CONFIG_GIC_NON_BANKED
+       if (percpu_offset) { /* Frankein-GIC without banked registers... */
+               unsigned int cpu;
+
+               gic->dist_base.percpu_base = alloc_percpu(void __iomem *);
+               gic->cpu_base.percpu_base = alloc_percpu(void __iomem *);
+               if (WARN_ON(!gic->dist_base.percpu_base ||
+                           !gic->cpu_base.percpu_base)) {
+                       free_percpu(gic->dist_base.percpu_base);
+                       free_percpu(gic->cpu_base.percpu_base);
+                       return;
+               }
+
+               for_each_possible_cpu(cpu) {
+                       unsigned long offset = percpu_offset * cpu_logical_map(cpu);
+                       *per_cpu_ptr(gic->dist_base.percpu_base, cpu) = dist_base + offset;
+                       *per_cpu_ptr(gic->cpu_base.percpu_base, cpu) = cpu_base + offset;
+               }
+
+               gic_set_base_accessor(gic, gic_get_percpu_base);
+       } else
+#endif
+       {                       /* Normal, sane GIC... */
+               WARN(percpu_offset,
+                    "GIC_NON_BANKED not enabled, ignoring %08x offset!",
+                    percpu_offset);
+               gic->dist_base.common_base = dist_base;
+               gic->cpu_base.common_base = cpu_base;
+               gic_set_base_accessor(gic, gic_get_common_base);
+       }
 
        /*
         * For primary GICs, skip over SGIs.
@@ -593,7 +684,7 @@ void __init gic_init(unsigned int gic_nr, int irq_start,
         * Find out how many interrupts are supported.
         * The GIC only supports up to 1020 interrupt sources.
         */
-       gic_irqs = readl_relaxed(dist_base + GIC_DIST_CTR) & 0x1f;
+       gic_irqs = readl_relaxed(gic_data_dist_base(gic) + GIC_DIST_CTR) & 0x1f;
        gic_irqs = (gic_irqs + 1) * 32;
        if (gic_irqs > 1020)
                gic_irqs = 1020;
@@ -641,7 +732,7 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
        dsb();
 
        /* this always happens on GIC0 */
-       writel_relaxed(map << 16 | irq, gic_data[0].dist_base + GIC_DIST_SOFTINT);
+       writel_relaxed(map << 16 | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
 }
 #endif
 
@@ -652,6 +743,7 @@ int __init gic_of_init(struct device_node *node, struct device_node *parent)
 {
        void __iomem *cpu_base;
        void __iomem *dist_base;
+       u32 percpu_offset;
        int irq;
        struct irq_domain *domain = &gic_data[gic_cnt].domain;
 
@@ -664,9 +756,12 @@ int __init gic_of_init(struct device_node *node, struct device_node *parent)
        cpu_base = of_iomap(node, 1);
        WARN(!cpu_base, "unable to map gic cpu registers\n");
 
+       if (of_property_read_u32(node, "cpu-offset", &percpu_offset))
+               percpu_offset = 0;
+
        domain->of_node = of_node_get(node);
 
-       gic_init(gic_cnt, -1, dist_base, cpu_base);
+       gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset);
 
        if (parent) {
                irq = irq_of_parse_and_map(node, 0);

diff --git a/arch/arm/include/asm/hardware/gic.h b/arch/arm/include/asm/hardware/gic.h
index 3e91f22046f55d602550c1a0961312f2c9d4ba33..2721d90625e59f5d91a924bb60aefdacdf9fa6c1 100644 (file)
--- a/arch/arm/include/asm/hardware/gic.h
+++ b/arch/arm/include/asm/hardware/gic.h
@@ -39,27 +39,19 @@ struct device_node;
 extern void __iomem *gic_cpu_base_addr;
 extern struct irq_chip gic_arch_extn;
 
-void gic_init(unsigned int, int, void __iomem *, void __iomem *);
+void gic_init_bases(unsigned int, int, void __iomem *, void __iomem *,
+                   u32 offset);
 int gic_of_init(struct device_node *node, struct device_node *parent);
 void gic_secondary_init(unsigned int);
 void gic_cascade_irq(unsigned int gic_nr, unsigned int irq);
 void gic_raise_softirq(const struct cpumask *mask, unsigned int irq);
 
-struct gic_chip_data {
-       void __iomem *dist_base;
-       void __iomem *cpu_base;
-#ifdef CONFIG_CPU_PM
-       u32 saved_spi_enable[DIV_ROUND_UP(1020, 32)];
-       u32 saved_spi_conf[DIV_ROUND_UP(1020, 16)];
-       u32 saved_spi_target[DIV_ROUND_UP(1020, 4)];
-       u32 __percpu *saved_ppi_enable;
-       u32 __percpu *saved_ppi_conf;
-#endif
-#ifdef CONFIG_IRQ_DOMAIN
-       struct irq_domain domain;
-#endif
-       unsigned int gic_irqs;
-};
+static inline void gic_init(unsigned int nr, int start,
+                           void __iomem *dist , void __iomem *cpu)
+{
+       gic_init_bases(nr, start, dist, cpu, 0);
+}
+
 #endif
 
 #endif

diff --git a/arch/arm/mach-exynos/cpu.c b/arch/arm/mach-exynos/cpu.c
index 90ec247f3b375f498e20f46c20e25fe2c943b54a..e92e464bdbba7d8d0e7302ccb58660742b3cad6d 100644 (file)
--- a/arch/arm/mach-exynos/cpu.c
+++ b/arch/arm/mach-exynos/cpu.c
@@ -207,27 +207,13 @@ void __init exynos4_init_clocks(int xtal)
        exynos4_setup_clocks();
 }
 
-static void exynos4_gic_irq_fix_base(struct irq_data *d)
-{
-       struct gic_chip_data *gic_data = irq_data_get_irq_chip_data(d);
-
-       gic_data->cpu_base = S5P_VA_GIC_CPU +
-                           (gic_bank_offset * smp_processor_id());
-
-       gic_data->dist_base = S5P_VA_GIC_DIST +
-                           (gic_bank_offset * smp_processor_id());
-}
-
 void __init exynos4_init_irq(void)
 {
        int irq;
 
        gic_bank_offset = soc_is_exynos4412() ? 0x4000 : 0x8000;
 
-       gic_init(0, IRQ_PPI(0), S5P_VA_GIC_DIST, S5P_VA_GIC_CPU);
-       gic_arch_extn.irq_eoi = exynos4_gic_irq_fix_base;
-       gic_arch_extn.irq_unmask = exynos4_gic_irq_fix_base;
-       gic_arch_extn.irq_mask = exynos4_gic_irq_fix_base;
+       gic_init_bases(0, IRQ_PPI(0), S5P_VA_GIC_DIST, S5P_VA_GIC_CPU, gic_bank_offset);
 
        for (irq = 0; irq < MAX_COMBINER_NR; irq++) {
 

diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
index 69ffb2fb38755c795a541903e0a4071237be71fa..60bc45e3e7099045560f71bf4aaf29664341e488 100644 (file)
--- a/arch/arm/mach-exynos/platsmp.c
+++ b/arch/arm/mach-exynos/platsmp.c
@@ -32,7 +32,6 @@
 
 #include <plat/cpu.h>
 
-extern unsigned int gic_bank_offset;
 extern void exynos4_secondary_startup(void);
 
 #define CPU1_BOOT_REG          (samsung_rev() == EXYNOS4210_REV_1_1 ? \
@@ -65,31 +64,6 @@ static void __iomem *scu_base_addr(void)
 
 static DEFINE_SPINLOCK(boot_lock);
 
-static void __cpuinit exynos4_gic_secondary_init(void)
-{
-       void __iomem *dist_base = S5P_VA_GIC_DIST +
-                               (gic_bank_offset * smp_processor_id());
-       void __iomem *cpu_base = S5P_VA_GIC_CPU +
-                               (gic_bank_offset * smp_processor_id());
-       int i;
-
-       /*
-        * Deal with the banked PPI and SGI interrupts - disable all
-        * PPI interrupts, ensure all SGI interrupts are enabled.
-        */
-       __raw_writel(0xffff0000, dist_base + GIC_DIST_ENABLE_CLEAR);
-       __raw_writel(0x0000ffff, dist_base + GIC_DIST_ENABLE_SET);
-
-       /*
-        * Set priority on PPI and SGI interrupts
-        */
-       for (i = 0; i < 32; i += 4)
-               __raw_writel(0xa0a0a0a0, dist_base + GIC_DIST_PRI + i * 4 / 4);
-
-       __raw_writel(0xf0, cpu_base + GIC_CPU_PRIMASK);
-       __raw_writel(1, cpu_base + GIC_CPU_CTRL);
-}
-
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
        /*
@@ -97,7 +71,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
         * core (e.g. timer irq), then they will not have been enabled
         * for us: do so
         */
-       exynos4_gic_secondary_init();
+       gic_secondary_init(0);
 
        /*
         * let the primary processor know we're out of the

diff --git a/arch/arm/plat-s5p/Kconfig b/arch/arm/plat-s5p/Kconfig
index 9b9968fa8695b05b0fa4edb3784dc90fd000126f..8167ce66188c65c19f6d9efda34b718f7acf7c0b 100644 (file)
--- a/arch/arm/plat-s5p/Kconfig
+++ b/arch/arm/plat-s5p/Kconfig
@@ -11,6 +11,7 @@ config PLAT_S5P
        default y
        select ARM_VIC if !ARCH_EXYNOS4
        select ARM_GIC if ARCH_EXYNOS4
+       select GIC_NON_BANKED if ARCH_EXYNOS4
        select NO_IOPORT
        select ARCH_REQUIRE_GPIOLIB
        select S3C_GPIO_TRACK