x86: HPET_MSI Basic HPET_MSI setup code

Basic HPET MSI setup code. Routines to perform basic MSI read write
in HPET memory map and setting up irq_chip for HPET MSI.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 118 insertions, 0 deletions

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index f7cb5e9e261e..3f10d16a8348 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -6,6 +6,8 @@
 #include <linux/init.h>
 #include <linux/sysdev.h>
 #include <linux/pm.h>
+#include <linux/interrupt.h>
+#include <linux/cpu.h>
 
 #include <asm/fixmap.h>
 #include <asm/hpet.h>
@@ -25,6 +27,15 @@
 unsigned long hpet_address;
 static void __iomem *hpet_virt_address;
 
+struct hpet_dev {
+        struct clock_event_device evt;
+        unsigned int num;
+        int cpu;
+        unsigned int irq;
+        unsigned int flags;
+        char name[10];
+};
+
 unsigned long hpet_readl(unsigned long a)
 {
         return readl(hpet_virt_address + a);
@@ -305,6 +316,49 @@ static int hpet_legacy_next_event(unsigned long delta,
 }
 
 /*
+ * HPET MSI Support
+ */
+
+void hpet_msi_unmask(unsigned int irq)
+{
+        struct hpet_dev *hdev = get_irq_data(irq);
+        unsigned long cfg;
+
+        /* unmask it */
+        cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
+        cfg |= HPET_TN_FSB;
+        hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
+}
+
+void hpet_msi_mask(unsigned int irq)
+{
+        unsigned long cfg;
+        struct hpet_dev *hdev = get_irq_data(irq);
+
+        /* mask it */
+        cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
+        cfg &= ~HPET_TN_FSB;
+        hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
+}
+
+void hpet_msi_write(unsigned int irq, struct msi_msg *msg)
+{
+        struct hpet_dev *hdev = get_irq_data(irq);
+
+        hpet_writel(msg->data, HPET_Tn_ROUTE(hdev->num));
+        hpet_writel(msg->address_lo, HPET_Tn_ROUTE(hdev->num) + 4);
+}
+
+void hpet_msi_read(unsigned int irq, struct msi_msg *msg)
+{
+        struct hpet_dev *hdev = get_irq_data(irq);
+
+        msg->data = hpet_readl(HPET_Tn_ROUTE(hdev->num));
+        msg->address_lo = hpet_readl(HPET_Tn_ROUTE(hdev->num) + 4);
+        msg->address_hi = 0;
+}
+
+/*
  * Clock source related code
  */
 static cycle_t read_hpet(void)
diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index d22fecf828b8..77fa155becf6 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -41,6 +41,7 @@
 #endif
 #include <linux/bootmem.h>
 #include <linux/dmar.h>
+#include <linux/hpet.h>
 
 #include <asm/idle.h>
 #include <asm/io.h>
@@ -56,6 +57,7 @@
 #include <asm/hypertransport.h>
 #include <asm/setup.h>
 #include <asm/irq_remapping.h>
+#include <asm/hpet.h>
 
 #include <mach_ipi.h>
 #include <mach_apic.h>
@@ -3522,6 +3524,68 @@ int arch_setup_dmar_msi(unsigned int irq)
 }
 #endif
 
+#ifdef CONFIG_HPET_TIMER
+
+#ifdef CONFIG_SMP
+static void hpet_msi_set_affinity(unsigned int irq, cpumask_t mask)
+{
+        struct irq_cfg *cfg;
+        struct irq_desc *desc;
+        struct msi_msg msg;
+        unsigned int dest;
+        cpumask_t tmp;
+
+        cpus_and(tmp, mask, cpu_online_map);
+        if (cpus_empty(tmp))
+                return;
+
+        if (assign_irq_vector(irq, mask))
+                return;
+
+        cfg = irq_cfg(irq);
+        cpus_and(tmp, cfg->domain, mask);
+        dest = cpu_mask_to_apicid(tmp);
+
+        hpet_msi_read(irq, &msg);
+
+        msg.data &= ~MSI_DATA_VECTOR_MASK;
+        msg.data |= MSI_DATA_VECTOR(cfg->vector);
+        msg.address_lo &= ~MSI_ADDR_DEST_ID_MASK;
+        msg.address_lo |= MSI_ADDR_DEST_ID(dest);
+
+        hpet_msi_write(irq, &msg);
+        desc = irq_to_desc(irq);
+        desc->affinity = mask;
+}
+#endif /* CONFIG_SMP */
+
+struct irq_chip hpet_msi_type = {
+        .name = "HPET_MSI",
+        .unmask = hpet_msi_unmask,
+        .mask = hpet_msi_mask,
+        .ack = ack_apic_edge,
+#ifdef CONFIG_SMP
+        .set_affinity = hpet_msi_set_affinity,
+#endif
+        .retrigger = ioapic_retrigger_irq,
+};
+
+int arch_setup_hpet_msi(unsigned int irq)
+{
+        int ret;
+        struct msi_msg msg;
+
+        ret = msi_compose_msg(NULL, irq, &msg);
+        if (ret < 0)
+                return ret;
+
+        hpet_msi_write(irq, &msg);
+        set_irq_chip_and_handler_name(irq, &hpet_msi_type, handle_edge_irq,
+                "edge");
+        return 0;
+}
+#endif
+
 #endif /* CONFIG_PCI_MSI */
 /*
  * Hypertransport interrupt support