powerpc/xics: Rewrite XICS driver

This is a significant rework of the XICS driver, too significant to
conveniently break it up into a series of smaller patches to be honest.

The driver is moved to a more generic location to allow new platforms
to use it, and is broken up into separate ICP and ICS "backends". For
now we have the native and "hypervisor" ICP backends and one common
RTAS ICS backend.

The driver supports one ICP backend instanciation, and many ICS ones,
in order to accomodate future platforms with multiple possibly different
interrupt "sources" mechanisms.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 145 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index 67ab5fb7d153..47b7905a6369 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -142,6 +142,12 @@ extern struct irq_map_entry irq_map[NR_IRQS];
 
 extern irq_hw_number_t virq_to_hw(unsigned int virq);
 
+/* This will eventually -replace- virq_to_hw if/when we stash the
+ * HW number in the irq_data itself. We use a macro so we can inline
+ * it as irq_data isn't defined yet
+ */
+#define irq_data_to_hw(d) (irq_map[(d)->irq].hwirq)
+
 /**
  * irq_alloc_host - Allocate a new irq_host data structure
  * @of_node: optional device-tree node of the interrupt controller
diff --git a/arch/powerpc/include/asm/xics.h b/arch/powerpc/include/asm/xics.h
new file mode 100644
index 000000000000..146aad8534de
--- /dev/null
+++ b/arch/powerpc/include/asm/xics.h
@@ -0,0 +1,139 @@
+/*
+ * Common definitions accross all variants of ICP and ICS interrupt
+ * controllers.
+ */
+
+#ifndef _XICS_H
+#define _XICS_H
+
+#define XICS_IPI                2
+#define XICS_IRQ_SPURIOUS       0
+
+/* Want a priority other than 0.  Various HW issues require this. */
+#define DEFAULT_PRIORITY        5
+
+/*
+ * Mark IPIs as higher priority so we can take them inside interrupts that
+ * arent marked IRQF_DISABLED
+ */
+#define IPI_PRIORITY            4
+
+/* The least favored priority */
+#define LOWEST_PRIORITY         0xFF
+
+/* The number of priorities defined above */
+#define MAX_NUM_PRIORITIES      3
+
+/* Native ICP */
+extern int icp_native_init(void);
+
+/* PAPR ICP */
+extern int icp_hv_init(void);
+
+/* ICP ops */
+struct icp_ops {
+        unsigned int (*get_irq)(void);
+        void (*eoi)(struct irq_data *d);
+        void (*set_priority)(unsigned char prio);
+        void (*teardown_cpu)(void);
+        void (*flush_ipi)(void);
+#ifdef CONFIG_SMP
+        void (*message_pass)(int target, int msg);
+        irq_handler_t ipi_action;
+#endif
+};
+
+extern const struct icp_ops *icp_ops;
+
+/* Native ICS */
+extern int ics_native_init(void);
+
+/* RTAS ICS */
+extern int ics_rtas_init(void);
+
+/* ICS instance, hooked up to chip_data of an irq */
+struct ics {
+        struct list_head link;
+        int (*map)(struct ics *ics, unsigned int virq);
+        void (*mask_unknown)(struct ics *ics, unsigned long vec);
+        long (*get_server)(struct ics *ics, unsigned long vec);
+        char data[];
+};
+
+/* Commons */
+extern unsigned int xics_default_server;
+extern unsigned int xics_default_distrib_server;
+extern unsigned int xics_interrupt_server_size;
+extern struct irq_host *xics_host;
+
+struct xics_cppr {
+        unsigned char stack[MAX_NUM_PRIORITIES];
+        int index;
+};
+
+DECLARE_PER_CPU(struct xics_cppr, xics_cppr);
+
+static inline void xics_push_cppr(unsigned int vec)
+{
+        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+
+        if (WARN_ON(os_cppr->index >= MAX_NUM_PRIORITIES - 1))
+                return;
+
+        if (vec == XICS_IPI)
+                os_cppr->stack[++os_cppr->index] = IPI_PRIORITY;
+        else
+                os_cppr->stack[++os_cppr->index] = DEFAULT_PRIORITY;
+}
+
+static inline unsigned char xics_pop_cppr(void)
+{
+        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+
+        if (WARN_ON(os_cppr->index < 1))
+                return LOWEST_PRIORITY;
+
+        return os_cppr->stack[--os_cppr->index];
+}
+
+static inline void xics_set_base_cppr(unsigned char cppr)
+{
+        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+
+        /* we only really want to set the priority when there's
+         * just one cppr value on the stack
+         */
+        WARN_ON(os_cppr->index != 0);
+
+        os_cppr->stack[0] = cppr;
+}
+
+static inline unsigned char xics_cppr_top(void)
+{
+        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+        
+        return os_cppr->stack[os_cppr->index];
+}
+
+DECLARE_PER_CPU_SHARED_ALIGNED(unsigned long, xics_ipi_message);
+
+extern void xics_init(void);
+extern void xics_setup_cpu(void);
+extern void xics_update_irq_servers(void);
+extern void xics_set_cpu_giq(unsigned int gserver, unsigned int join);
+extern void xics_mask_unknown_vec(unsigned int vec);
+extern irqreturn_t xics_ipi_dispatch(int cpu);
+extern int xics_smp_probe(void);
+extern void xics_register_ics(struct ics *ics);
+extern void xics_teardown_cpu(void);
+extern void xics_kexec_teardown_cpu(int secondary);
+extern void xics_migrate_irqs_away(void);
+#ifdef CONFIG_SMP
+extern int xics_get_irq_server(unsigned int virq, const struct cpumask *cpumask,
+                               unsigned int strict_check);
+#else
+#define xics_get_irq_server(virq, cpumask, strict_check) (xics_default_server)
+#endif
+
+
+#endif /* _XICS_H */