MIPS: Add code for new system 'paravirt'
For para-virtualized guests running under KVM or other equivalent
hypervisor.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7004/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/paravirt/paravirt-irq.c b/arch/mips/paravirt/paravirt-irq.c
new file mode 100644
index 0000000..8987b06
--- /dev/null
+++ b/arch/mips/paravirt/paravirt-irq.c
@@ -0,0 +1,368 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2013 Cavium, Inc.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/cpumask.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+
+#include <asm/io.h>
+
+#define MBOX_BITS_PER_CPU 2
+
+static int cpunum_for_cpu(int cpu)
+{
+#ifdef CONFIG_SMP
+ return cpu_logical_map(cpu);
+#else
+ return get_ebase_cpunum();
+#endif
+}
+
+struct core_chip_data {
+ struct mutex core_irq_mutex;
+ bool current_en;
+ bool desired_en;
+ u8 bit;
+};
+
+static struct core_chip_data irq_core_chip_data[8];
+
+static void irq_core_ack(struct irq_data *data)
+{
+ struct core_chip_data *cd = irq_data_get_irq_chip_data(data);
+ unsigned int bit = cd->bit;
+
+ /*
+ * We don't need to disable IRQs to make these atomic since
+ * they are already disabled earlier in the low level
+ * interrupt code.
+ */
+ clear_c0_status(0x100 << bit);
+ /* The two user interrupts must be cleared manually. */
+ if (bit < 2)
+ clear_c0_cause(0x100 << bit);
+}
+
+static void irq_core_eoi(struct irq_data *data)
+{
+ struct core_chip_data *cd = irq_data_get_irq_chip_data(data);
+
+ /*
+ * We don't need to disable IRQs to make these atomic since
+ * they are already disabled earlier in the low level
+ * interrupt code.
+ */
+ set_c0_status(0x100 << cd->bit);
+}
+
+static void irq_core_set_enable_local(void *arg)
+{
+ struct irq_data *data = arg;
+ struct core_chip_data *cd = irq_data_get_irq_chip_data(data);
+ unsigned int mask = 0x100 << cd->bit;
+
+ /*
+ * Interrupts are already disabled, so these are atomic.
+ */
+ if (cd->desired_en)
+ set_c0_status(mask);
+ else
+ clear_c0_status(mask);
+
+}
+
+static void irq_core_disable(struct irq_data *data)
+{
+ struct core_chip_data *cd = irq_data_get_irq_chip_data(data);
+ cd->desired_en = false;
+}
+
+static void irq_core_enable(struct irq_data *data)
+{
+ struct core_chip_data *cd = irq_data_get_irq_chip_data(data);
+ cd->desired_en = true;
+}
+
+static void irq_core_bus_lock(struct irq_data *data)
+{
+ struct core_chip_data *cd = irq_data_get_irq_chip_data(data);
+
+ mutex_lock(&cd->core_irq_mutex);
+}
+
+static void irq_core_bus_sync_unlock(struct irq_data *data)
+{
+ struct core_chip_data *cd = irq_data_get_irq_chip_data(data);
+
+ if (cd->desired_en != cd->current_en) {
+ on_each_cpu(irq_core_set_enable_local, data, 1);
+ cd->current_en = cd->desired_en;
+ }
+
+ mutex_unlock(&cd->core_irq_mutex);
+}
+
+static struct irq_chip irq_chip_core = {
+ .name = "Core",
+ .irq_enable = irq_core_enable,
+ .irq_disable = irq_core_disable,
+ .irq_ack = irq_core_ack,
+ .irq_eoi = irq_core_eoi,
+ .irq_bus_lock = irq_core_bus_lock,
+ .irq_bus_sync_unlock = irq_core_bus_sync_unlock,
+
+ .irq_cpu_online = irq_core_eoi,
+ .irq_cpu_offline = irq_core_ack,
+ .flags = IRQCHIP_ONOFFLINE_ENABLED,
+};
+
+static void __init irq_init_core(void)
+{
+ int i;
+ int irq;
+ struct core_chip_data *cd;
+
+ /* Start with a clean slate */
+ clear_c0_status(ST0_IM);
+ clear_c0_cause(CAUSEF_IP0 | CAUSEF_IP1);
+
+ for (i = 0; i < ARRAY_SIZE(irq_core_chip_data); i++) {
+ cd = irq_core_chip_data + i;
+ cd->current_en = false;
+ cd->desired_en = false;
+ cd->bit = i;
+ mutex_init(&cd->core_irq_mutex);
+
+ irq = MIPS_CPU_IRQ_BASE + i;
+
+ switch (i) {
+ case 0: /* SW0 */
+ case 1: /* SW1 */
+ case 5: /* IP5 */
+ case 6: /* IP6 */
+ case 7: /* IP7 */
+ irq_set_chip_data(irq, cd);
+ irq_set_chip_and_handler(irq, &irq_chip_core,
+ handle_percpu_irq);
+ break;
+ default:
+ break;
+ }
+ }
+}
+
+static void __iomem *mips_irq_chip;
+#define MIPS_IRQ_CHIP_NUM_BITS 0
+#define MIPS_IRQ_CHIP_REGS 8
+
+static int mips_irq_cpu_stride;
+static int mips_irq_chip_reg_raw;
+static int mips_irq_chip_reg_src;
+static int mips_irq_chip_reg_en;
+static int mips_irq_chip_reg_raw_w1s;
+static int mips_irq_chip_reg_raw_w1c;
+static int mips_irq_chip_reg_en_w1s;
+static int mips_irq_chip_reg_en_w1c;
+
+static void irq_pci_enable(struct irq_data *data)
+{
+ u32 mask = 1u << data->irq;
+
+ __raw_writel(mask, mips_irq_chip + mips_irq_chip_reg_en_w1s);
+}
+
+static void irq_pci_disable(struct irq_data *data)
+{
+ u32 mask = 1u << data->irq;
+
+ __raw_writel(mask, mips_irq_chip + mips_irq_chip_reg_en_w1c);
+}
+
+static void irq_pci_ack(struct irq_data *data)
+{
+}
+
+static void irq_pci_mask(struct irq_data *data)
+{
+ u32 mask = 1u << data->irq;
+
+ __raw_writel(mask, mips_irq_chip + mips_irq_chip_reg_en_w1c);
+}
+
+static void irq_pci_unmask(struct irq_data *data)
+{
+ u32 mask = 1u << data->irq;
+
+ __raw_writel(mask, mips_irq_chip + mips_irq_chip_reg_en_w1s);
+}
+
+static struct irq_chip irq_chip_pci = {
+ .name = "PCI",
+ .irq_enable = irq_pci_enable,
+ .irq_disable = irq_pci_disable,
+ .irq_ack = irq_pci_ack,
+ .irq_mask = irq_pci_mask,
+ .irq_unmask = irq_pci_unmask,
+};
+
+static void irq_mbox_all(struct irq_data *data, void __iomem *base)
+{
+ int cpu;
+ unsigned int mbox = data->irq - MIPS_IRQ_MBOX0;
+ u32 mask;
+
+ WARN_ON(mbox >= MBOX_BITS_PER_CPU);
+
+ for_each_online_cpu(cpu) {
+ unsigned int cpuid = cpunum_for_cpu(cpu);
+ mask = 1 << (cpuid * MBOX_BITS_PER_CPU + mbox);
+ __raw_writel(mask, base + (cpuid * mips_irq_cpu_stride));
+ }
+}
+
+static void irq_mbox_enable(struct irq_data *data)
+{
+ irq_mbox_all(data, mips_irq_chip + mips_irq_chip_reg_en_w1s + sizeof(u32));
+}
+
+static void irq_mbox_disable(struct irq_data *data)
+{
+ irq_mbox_all(data, mips_irq_chip + mips_irq_chip_reg_en_w1c + sizeof(u32));
+}
+
+static void irq_mbox_ack(struct irq_data *data)
+{
+ u32 mask;
+ unsigned int mbox = data->irq - MIPS_IRQ_MBOX0;
+
+ WARN_ON(mbox >= MBOX_BITS_PER_CPU);
+
+ mask = 1 << (get_ebase_cpunum() * MBOX_BITS_PER_CPU + mbox);
+ __raw_writel(mask, mips_irq_chip + mips_irq_chip_reg_raw_w1c + sizeof(u32));
+}
+
+void irq_mbox_ipi(int cpu, unsigned int actions)
+{
+ unsigned int cpuid = cpunum_for_cpu(cpu);
+ u32 mask;
+
+ WARN_ON(actions >= (1 << MBOX_BITS_PER_CPU));
+
+ mask = actions << (cpuid * MBOX_BITS_PER_CPU);
+ __raw_writel(mask, mips_irq_chip + mips_irq_chip_reg_raw_w1s + sizeof(u32));
+}
+
+static void irq_mbox_cpu_onoffline(struct irq_data *data, void __iomem *base)
+{
+ unsigned int mbox = data->irq - MIPS_IRQ_MBOX0;
+ unsigned int cpuid = get_ebase_cpunum();
+ u32 mask;
+
+ WARN_ON(mbox >= MBOX_BITS_PER_CPU);
+
+ mask = 1 << (cpuid * MBOX_BITS_PER_CPU + mbox);
+ __raw_writel(mask, base + (cpuid * mips_irq_cpu_stride));
+
+}
+
+static void irq_mbox_cpu_online(struct irq_data *data)
+{
+ irq_mbox_cpu_onoffline(data, mips_irq_chip + mips_irq_chip_reg_en_w1s + sizeof(u32));
+}
+
+static void irq_mbox_cpu_offline(struct irq_data *data)
+{
+ irq_mbox_cpu_onoffline(data, mips_irq_chip + mips_irq_chip_reg_en_w1c + sizeof(u32));
+}
+
+static struct irq_chip irq_chip_mbox = {
+ .name = "MBOX",
+ .irq_enable = irq_mbox_enable,
+ .irq_disable = irq_mbox_disable,
+ .irq_ack = irq_mbox_ack,
+ .irq_cpu_online = irq_mbox_cpu_online,
+ .irq_cpu_offline = irq_mbox_cpu_offline,
+ .flags = IRQCHIP_ONOFFLINE_ENABLED,
+};
+
+static void __init irq_pci_init(void)
+{
+ int i, stride;
+ u32 num_bits;
+
+ mips_irq_chip = ioremap(0x1e010000, 4096);
+
+ num_bits = __raw_readl(mips_irq_chip + MIPS_IRQ_CHIP_NUM_BITS);
+ stride = 8 * (1 + ((num_bits - 1) / 64));
+
+
+ pr_notice("mips_irq_chip: %u bits, reg stride: %d\n", num_bits, stride);
+ mips_irq_chip_reg_raw = MIPS_IRQ_CHIP_REGS + 0 * stride;
+ mips_irq_chip_reg_raw_w1s = MIPS_IRQ_CHIP_REGS + 1 * stride;
+ mips_irq_chip_reg_raw_w1c = MIPS_IRQ_CHIP_REGS + 2 * stride;
+ mips_irq_chip_reg_src = MIPS_IRQ_CHIP_REGS + 3 * stride;
+ mips_irq_chip_reg_en = MIPS_IRQ_CHIP_REGS + 4 * stride;
+ mips_irq_chip_reg_en_w1s = MIPS_IRQ_CHIP_REGS + 5 * stride;
+ mips_irq_chip_reg_en_w1c = MIPS_IRQ_CHIP_REGS + 6 * stride;
+ mips_irq_cpu_stride = stride * 4;
+
+ for (i = 0; i < 4; i++)
+ irq_set_chip_and_handler(i + MIPS_IRQ_PCIA, &irq_chip_pci, handle_level_irq);
+
+ for (i = 0; i < 2; i++)
+ irq_set_chip_and_handler(i + MIPS_IRQ_MBOX0, &irq_chip_mbox, handle_percpu_irq);
+
+
+ set_c0_status(STATUSF_IP2);
+}
+
+static void irq_pci_dispatch(void)
+{
+ unsigned int cpuid = get_ebase_cpunum();
+ u32 en;
+
+ en = __raw_readl(mips_irq_chip + mips_irq_chip_reg_src +
+ (cpuid * mips_irq_cpu_stride));
+
+ if (!en) {
+ en = __raw_readl(mips_irq_chip + mips_irq_chip_reg_src + (cpuid * mips_irq_cpu_stride) + sizeof(u32));
+ en = (en >> (2 * cpuid)) & 3;
+
+ if (!en)
+ spurious_interrupt();
+ else
+ do_IRQ(__ffs(en) + MIPS_IRQ_MBOX0); /* MBOX type */
+ } else {
+ do_IRQ(__ffs(en));
+ }
+}
+
+
+void __init arch_init_irq(void)
+{
+ irq_init_core();
+ irq_pci_init();
+}
+
+asmlinkage void plat_irq_dispatch(void)
+{
+ unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
+ int ip;
+
+ if (unlikely(!pending)) {
+ spurious_interrupt();
+ return;
+ }
+
+ ip = ffs(pending) - 1 - STATUSB_IP0;
+ if (ip == 2)
+ irq_pci_dispatch();
+ else
+ do_IRQ(MIPS_CPU_IRQ_BASE + ip);
+}