MIPS: Add initial support for the Atheros AR71XX/AR724X/AR931X SoCs

This patch adds initial support for various Atheros SoCs based on the
MIPS 24Kc core. The following models are supported at the moment:

  - AR7130
  - AR7141
  - AR7161
  - AR9130
  - AR9132
  - AR7240
  - AR7241
  - AR7242

The current patch contains minimal support only, but the resulting
kernel can boot into user-space with using of an initramfs image on
various boards which are using these SoCs. Support for more built-in
devices and individual boards will be implemented in further patches.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1947/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 187 insertions, 0 deletions

diff --git a/arch/mips/ath79/irq.c b/arch/mips/ath79/irq.c
new file mode 100644
index 000000000000..1bf7f719ba53
--- /dev/null
+++ b/arch/mips/ath79/irq.c
@@ -0,0 +1,187 @@
+/*
+ *  Atheros AR71xx/AR724x/AR913x specific interrupt handling
+ *
+ *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  Parts of this file are based on Atheros' 2.6.15 BSP
+ *
+ *  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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include <asm/irq_cpu.h>
+#include <asm/mipsregs.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include "common.h"
+
+static unsigned int ath79_ip2_flush_reg;
+static unsigned int ath79_ip3_flush_reg;
+
+static void ath79_misc_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+        void __iomem *base = ath79_reset_base;
+        u32 pending;
+
+        pending = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_STATUS) &
+                  __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+
+        if (pending & MISC_INT_UART)
+                generic_handle_irq(ATH79_MISC_IRQ_UART);
+
+        else if (pending & MISC_INT_DMA)
+                generic_handle_irq(ATH79_MISC_IRQ_DMA);
+
+        else if (pending & MISC_INT_PERFC)
+                generic_handle_irq(ATH79_MISC_IRQ_PERFC);
+
+        else if (pending & MISC_INT_TIMER)
+                generic_handle_irq(ATH79_MISC_IRQ_TIMER);
+
+        else if (pending & MISC_INT_OHCI)
+                generic_handle_irq(ATH79_MISC_IRQ_OHCI);
+
+        else if (pending & MISC_INT_ERROR)
+                generic_handle_irq(ATH79_MISC_IRQ_ERROR);
+
+        else if (pending & MISC_INT_GPIO)
+                generic_handle_irq(ATH79_MISC_IRQ_GPIO);
+
+        else if (pending & MISC_INT_WDOG)
+                generic_handle_irq(ATH79_MISC_IRQ_WDOG);
+
+        else
+                spurious_interrupt();
+}
+
+static void ar71xx_misc_irq_unmask(unsigned int irq)
+{
+        void __iomem *base = ath79_reset_base;
+        u32 t;
+
+        irq -= ATH79_MISC_IRQ_BASE;
+
+        t = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+        __raw_writel(t | (1 << irq), base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+
+        /* flush write */
+        __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+}
+
+static void ar71xx_misc_irq_mask(unsigned int irq)
+{
+        void __iomem *base = ath79_reset_base;
+        u32 t;
+
+        irq -= ATH79_MISC_IRQ_BASE;
+
+        t = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+        __raw_writel(t & ~(1 << irq), base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+
+        /* flush write */
+        __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+}
+
+static void ar724x_misc_irq_ack(unsigned int irq)
+{
+        void __iomem *base = ath79_reset_base;
+        u32 t;
+
+        irq -= ATH79_MISC_IRQ_BASE;
+
+        t = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_STATUS);
+        __raw_writel(t & ~(1 << irq), base + AR71XX_RESET_REG_MISC_INT_STATUS);
+
+        /* flush write */
+        __raw_readl(base + AR71XX_RESET_REG_MISC_INT_STATUS);
+}
+
+static struct irq_chip ath79_misc_irq_chip = {
+        .name           = "MISC",
+        .unmask         = ar71xx_misc_irq_unmask,
+        .mask           = ar71xx_misc_irq_mask,
+};
+
+static void __init ath79_misc_irq_init(void)
+{
+        void __iomem *base = ath79_reset_base;
+        int i;
+
+        __raw_writel(0, base + AR71XX_RESET_REG_MISC_INT_ENABLE);
+        __raw_writel(0, base + AR71XX_RESET_REG_MISC_INT_STATUS);
+
+        if (soc_is_ar71xx() || soc_is_ar913x())
+                ath79_misc_irq_chip.mask_ack = ar71xx_misc_irq_mask;
+        else if (soc_is_ar724x())
+                ath79_misc_irq_chip.ack = ar724x_misc_irq_ack;
+        else
+                BUG();
+
+        for (i = ATH79_MISC_IRQ_BASE;
+             i < ATH79_MISC_IRQ_BASE + ATH79_MISC_IRQ_COUNT; i++) {
+                irq_desc[i].status = IRQ_DISABLED;
+                set_irq_chip_and_handler(i, &ath79_misc_irq_chip,
+                                         handle_level_irq);
+        }
+
+        set_irq_chained_handler(ATH79_CPU_IRQ_MISC, ath79_misc_irq_handler);
+}
+
+asmlinkage void plat_irq_dispatch(void)
+{
+        unsigned long pending;
+
+        pending = read_c0_status() & read_c0_cause() & ST0_IM;
+
+        if (pending & STATUSF_IP7)
+                do_IRQ(ATH79_CPU_IRQ_TIMER);
+
+        else if (pending & STATUSF_IP2) {
+                ath79_ddr_wb_flush(ath79_ip2_flush_reg);
+                do_IRQ(ATH79_CPU_IRQ_IP2);
+        }
+
+        else if (pending & STATUSF_IP4)
+                do_IRQ(ATH79_CPU_IRQ_GE0);
+
+        else if (pending & STATUSF_IP5)
+                do_IRQ(ATH79_CPU_IRQ_GE1);
+
+        else if (pending & STATUSF_IP3) {
+                ath79_ddr_wb_flush(ath79_ip3_flush_reg);
+                do_IRQ(ATH79_CPU_IRQ_USB);
+        }
+
+        else if (pending & STATUSF_IP6)
+                do_IRQ(ATH79_CPU_IRQ_MISC);
+
+        else
+                spurious_interrupt();
+}
+
+void __init arch_init_irq(void)
+{
+        if (soc_is_ar71xx()) {
+                ath79_ip2_flush_reg = AR71XX_DDR_REG_FLUSH_PCI;
+                ath79_ip3_flush_reg = AR71XX_DDR_REG_FLUSH_USB;
+        } else if (soc_is_ar724x()) {
+                ath79_ip2_flush_reg = AR724X_DDR_REG_FLUSH_PCIE;
+                ath79_ip3_flush_reg = AR724X_DDR_REG_FLUSH_USB;
+        } else if (soc_is_ar913x()) {
+                ath79_ip2_flush_reg = AR913X_DDR_REG_FLUSH_WMAC;
+                ath79_ip3_flush_reg = AR913X_DDR_REG_FLUSH_USB;
+        } else
+                BUG();
+
+        cp0_perfcount_irq = ATH79_MISC_IRQ_PERFC;
+        mips_cpu_irq_init();
+        ath79_misc_irq_init();
+}