MIPS: Lantiq: Add initial support for Lantiq SoCs

Add initial support for Mips based SoCs made by Lantiq. This series will add
support for the XWAY family.

The series allows booting a minimal system using a initramfs or NOR. Missing
drivers and support for Amazon and GPON family will be provided in a later
series.

[Ralf: Remove some cargo cult programming and fixed formatting.]

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2252/
Patchwork: https://patchwork.linux-mips.org/patch/2371/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 326 insertions, 0 deletions

diff --git a/arch/mips/lantiq/irq.c b/arch/mips/lantiq/irq.c
new file mode 100644
index 000000000000..fc89795cafdb
--- /dev/null
+++ b/arch/mips/lantiq/irq.c
@@ -0,0 +1,326 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ * Copyright (C) 2010 John Crispin <blogic@openwrt.org>
+ * Copyright (C) 2010 Thomas Langer <thomas.langer@lantiq.com>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+
+#include <asm/bootinfo.h>
+#include <asm/irq_cpu.h>
+
+#include <lantiq_soc.h>
+#include <irq.h>
+
+/* register definitions */
+#define LTQ_ICU_IM0_ISR         0x0000
+#define LTQ_ICU_IM0_IER         0x0008
+#define LTQ_ICU_IM0_IOSR        0x0010
+#define LTQ_ICU_IM0_IRSR        0x0018
+#define LTQ_ICU_IM0_IMR         0x0020
+#define LTQ_ICU_IM1_ISR         0x0028
+#define LTQ_ICU_OFFSET          (LTQ_ICU_IM1_ISR - LTQ_ICU_IM0_ISR)
+
+#define LTQ_EIU_EXIN_C          0x0000
+#define LTQ_EIU_EXIN_INIC       0x0004
+#define LTQ_EIU_EXIN_INEN       0x000C
+
+/* irq numbers used by the external interrupt unit (EIU) */
+#define LTQ_EIU_IR0             (INT_NUM_IM4_IRL0 + 30)
+#define LTQ_EIU_IR1             (INT_NUM_IM3_IRL0 + 31)
+#define LTQ_EIU_IR2             (INT_NUM_IM1_IRL0 + 26)
+#define LTQ_EIU_IR3             INT_NUM_IM1_IRL0
+#define LTQ_EIU_IR4             (INT_NUM_IM1_IRL0 + 1)
+#define LTQ_EIU_IR5             (INT_NUM_IM1_IRL0 + 2)
+#define LTQ_EIU_IR6             (INT_NUM_IM2_IRL0 + 30)
+
+#define MAX_EIU                 6
+
+/* irqs generated by device attached to the EBU need to be acked in
+ * a special manner
+ */
+#define LTQ_ICU_EBU_IRQ         22
+
+#define ltq_icu_w32(x, y)       ltq_w32((x), ltq_icu_membase + (y))
+#define ltq_icu_r32(x)          ltq_r32(ltq_icu_membase + (x))
+
+#define ltq_eiu_w32(x, y)       ltq_w32((x), ltq_eiu_membase + (y))
+#define ltq_eiu_r32(x)          ltq_r32(ltq_eiu_membase + (x))
+
+static unsigned short ltq_eiu_irq[MAX_EIU] = {
+        LTQ_EIU_IR0,
+        LTQ_EIU_IR1,
+        LTQ_EIU_IR2,
+        LTQ_EIU_IR3,
+        LTQ_EIU_IR4,
+        LTQ_EIU_IR5,
+};
+
+static struct resource ltq_icu_resource = {
+        .name   = "icu",
+        .start  = LTQ_ICU_BASE_ADDR,
+        .end    = LTQ_ICU_BASE_ADDR + LTQ_ICU_SIZE - 1,
+        .flags  = IORESOURCE_MEM,
+};
+
+static struct resource ltq_eiu_resource = {
+        .name   = "eiu",
+        .start  = LTQ_EIU_BASE_ADDR,
+        .end    = LTQ_EIU_BASE_ADDR + LTQ_ICU_SIZE - 1,
+        .flags  = IORESOURCE_MEM,
+};
+
+static void __iomem *ltq_icu_membase;
+static void __iomem *ltq_eiu_membase;
+
+void ltq_disable_irq(struct irq_data *d)
+{
+        u32 ier = LTQ_ICU_IM0_IER;
+        int irq_nr = d->irq - INT_NUM_IRQ0;
+
+        ier += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
+        irq_nr %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32(ltq_icu_r32(ier) & ~(1 << irq_nr), ier);
+}
+
+void ltq_mask_and_ack_irq(struct irq_data *d)
+{
+        u32 ier = LTQ_ICU_IM0_IER;
+        u32 isr = LTQ_ICU_IM0_ISR;
+        int irq_nr = d->irq - INT_NUM_IRQ0;
+
+        ier += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
+        isr += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
+        irq_nr %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32(ltq_icu_r32(ier) & ~(1 << irq_nr), ier);
+        ltq_icu_w32((1 << irq_nr), isr);
+}
+
+static void ltq_ack_irq(struct irq_data *d)
+{
+        u32 isr = LTQ_ICU_IM0_ISR;
+        int irq_nr = d->irq - INT_NUM_IRQ0;
+
+        isr += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
+        irq_nr %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32((1 << irq_nr), isr);
+}
+
+void ltq_enable_irq(struct irq_data *d)
+{
+        u32 ier = LTQ_ICU_IM0_IER;
+        int irq_nr = d->irq - INT_NUM_IRQ0;
+
+        ier += LTQ_ICU_OFFSET  * (irq_nr / INT_NUM_IM_OFFSET);
+        irq_nr %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32(ltq_icu_r32(ier) | (1 << irq_nr), ier);
+}
+
+static unsigned int ltq_startup_eiu_irq(struct irq_data *d)
+{
+        int i;
+        int irq_nr = d->irq - INT_NUM_IRQ0;
+
+        ltq_enable_irq(d);
+        for (i = 0; i < MAX_EIU; i++) {
+                if (irq_nr == ltq_eiu_irq[i]) {
+                        /* low level - we should really handle set_type */
+                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_C) |
+                                (0x6 << (i * 4)), LTQ_EIU_EXIN_C);
+                        /* clear all pending */
+                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INIC) & ~(1 << i),
+                                LTQ_EIU_EXIN_INIC);
+                        /* enable */
+                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) | (1 << i),
+                                LTQ_EIU_EXIN_INEN);
+                        break;
+                }
+        }
+
+        return 0;
+}
+
+static void ltq_shutdown_eiu_irq(struct irq_data *d)
+{
+        int i;
+        int irq_nr = d->irq - INT_NUM_IRQ0;
+
+        ltq_disable_irq(d);
+        for (i = 0; i < MAX_EIU; i++) {
+                if (irq_nr == ltq_eiu_irq[i]) {
+                        /* disable */
+                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) & ~(1 << i),
+                                LTQ_EIU_EXIN_INEN);
+                        break;
+                }
+        }
+}
+
+static struct irq_chip ltq_irq_type = {
+        "icu",
+        .irq_enable = ltq_enable_irq,
+        .irq_disable = ltq_disable_irq,
+        .irq_unmask = ltq_enable_irq,
+        .irq_ack = ltq_ack_irq,
+        .irq_mask = ltq_disable_irq,
+        .irq_mask_ack = ltq_mask_and_ack_irq,
+};
+
+static struct irq_chip ltq_eiu_type = {
+        "eiu",
+        .irq_startup = ltq_startup_eiu_irq,
+        .irq_shutdown = ltq_shutdown_eiu_irq,
+        .irq_enable = ltq_enable_irq,
+        .irq_disable = ltq_disable_irq,
+        .irq_unmask = ltq_enable_irq,
+        .irq_ack = ltq_ack_irq,
+        .irq_mask = ltq_disable_irq,
+        .irq_mask_ack = ltq_mask_and_ack_irq,
+};
+
+static void ltq_hw_irqdispatch(int module)
+{
+        u32 irq;
+
+        irq = ltq_icu_r32(LTQ_ICU_IM0_IOSR + (module * LTQ_ICU_OFFSET));
+        if (irq == 0)
+                return;
+
+        /* silicon bug causes only the msb set to 1 to be valid. all
+         * other bits might be bogus
+         */
+        irq = __fls(irq);
+        do_IRQ((int)irq + INT_NUM_IM0_IRL0 + (INT_NUM_IM_OFFSET * module));
+
+        /* if this is a EBU irq, we need to ack it or get a deadlock */
+        if ((irq == LTQ_ICU_EBU_IRQ) && (module == 0))
+                ltq_ebu_w32(ltq_ebu_r32(LTQ_EBU_PCC_ISTAT) | 0x10,
+                        LTQ_EBU_PCC_ISTAT);
+}
+
+#define DEFINE_HWx_IRQDISPATCH(x)                                       \
+        static void ltq_hw ## x ## _irqdispatch(void)                   \
+        {                                                               \
+                ltq_hw_irqdispatch(x);                                  \
+        }
+DEFINE_HWx_IRQDISPATCH(0)
+DEFINE_HWx_IRQDISPATCH(1)
+DEFINE_HWx_IRQDISPATCH(2)
+DEFINE_HWx_IRQDISPATCH(3)
+DEFINE_HWx_IRQDISPATCH(4)
+
+static void ltq_hw5_irqdispatch(void)
+{
+        do_IRQ(MIPS_CPU_TIMER_IRQ);
+}
+
+asmlinkage void plat_irq_dispatch(void)
+{
+        unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM;
+        unsigned int i;
+
+        if (pending & CAUSEF_IP7) {
+                do_IRQ(MIPS_CPU_TIMER_IRQ);
+                goto out;
+        } else {
+                for (i = 0; i < 5; i++) {
+                        if (pending & (CAUSEF_IP2 << i)) {
+                                ltq_hw_irqdispatch(i);
+                                goto out;
+                        }
+                }
+        }
+        pr_alert("Spurious IRQ: CAUSE=0x%08x\n", read_c0_status());
+
+out:
+        return;
+}
+
+static struct irqaction cascade = {
+        .handler = no_action,
+        .flags = IRQF_DISABLED,
+        .name = "cascade",
+};
+
+void __init arch_init_irq(void)
+{
+        int i;
+
+        if (insert_resource(&iomem_resource, &ltq_icu_resource) < 0)
+                panic("Failed to insert icu memory\n");
+
+        if (request_mem_region(ltq_icu_resource.start,
+                        resource_size(&ltq_icu_resource), "icu") < 0)
+                panic("Failed to request icu memory\n");
+
+        ltq_icu_membase = ioremap_nocache(ltq_icu_resource.start,
+                                resource_size(&ltq_icu_resource));
+        if (!ltq_icu_membase)
+                panic("Failed to remap icu memory\n");
+
+        if (insert_resource(&iomem_resource, &ltq_eiu_resource) < 0)
+                panic("Failed to insert eiu memory\n");
+
+        if (request_mem_region(ltq_eiu_resource.start,
+                        resource_size(&ltq_eiu_resource), "eiu") < 0)
+                panic("Failed to request eiu memory\n");
+
+        ltq_eiu_membase = ioremap_nocache(ltq_eiu_resource.start,
+                                resource_size(&ltq_eiu_resource));
+        if (!ltq_eiu_membase)
+                panic("Failed to remap eiu memory\n");
+
+        /* make sure all irqs are turned off by default */
+        for (i = 0; i < 5; i++)
+                ltq_icu_w32(0, LTQ_ICU_IM0_IER + (i * LTQ_ICU_OFFSET));
+
+        /* clear all possibly pending interrupts */
+        ltq_icu_w32(~0, LTQ_ICU_IM0_ISR + (i * LTQ_ICU_OFFSET));
+
+        mips_cpu_irq_init();
+
+        for (i = 2; i <= 6; i++)
+                setup_irq(i, &cascade);
+
+        if (cpu_has_vint) {
+                pr_info("Setting up vectored interrupts\n");
+                set_vi_handler(2, ltq_hw0_irqdispatch);
+                set_vi_handler(3, ltq_hw1_irqdispatch);
+                set_vi_handler(4, ltq_hw2_irqdispatch);
+                set_vi_handler(5, ltq_hw3_irqdispatch);
+                set_vi_handler(6, ltq_hw4_irqdispatch);
+                set_vi_handler(7, ltq_hw5_irqdispatch);
+        }
+
+        for (i = INT_NUM_IRQ0;
+                i <= (INT_NUM_IRQ0 + (5 * INT_NUM_IM_OFFSET)); i++)
+                if ((i == LTQ_EIU_IR0) || (i == LTQ_EIU_IR1) ||
+                        (i == LTQ_EIU_IR2))
+                        irq_set_chip_and_handler(i, &ltq_eiu_type,
+                                handle_level_irq);
+                /* EIU3-5 only exist on ar9 and vr9 */
+                else if (((i == LTQ_EIU_IR3) || (i == LTQ_EIU_IR4) ||
+                        (i == LTQ_EIU_IR5)) && (ltq_is_ar9() || ltq_is_vr9()))
+                        irq_set_chip_and_handler(i, &ltq_eiu_type,
+                                handle_level_irq);
+                else
+                        irq_set_chip_and_handler(i, &ltq_irq_type,
+                                handle_level_irq);
+
+#if !defined(CONFIG_MIPS_MT_SMP) && !defined(CONFIG_MIPS_MT_SMTC)
+        set_c0_status(IE_IRQ0 | IE_IRQ1 | IE_IRQ2 |
+                IE_IRQ3 | IE_IRQ4 | IE_IRQ5);
+#else
+        set_c0_status(IE_SW0 | IE_SW1 | IE_IRQ0 | IE_IRQ1 |
+                IE_IRQ2 | IE_IRQ3 | IE_IRQ4 | IE_IRQ5);
+#endif
+}
+
+unsigned int __cpuinit get_c0_compare_int(void)
+{
+        return CP0_LEGACY_COMPARE_IRQ;
+}