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>

arch/mips/Kbuild.platforms

@@ -2,6 +2,7 @@
 
 platforms += alchemy
 platforms += ar7
+platforms += ath79
 platforms += bcm47xx
 platforms += bcm63xx
 platforms += cavium-octeon

arch/mips/Kconfig

@@ -66,6 +66,20 @@ config AR7
 	  Support for the Texas Instruments AR7 System-on-a-Chip
 	  family: TNETD7100, 7200 and 7300.
 
+config ATH79
+	bool "Atheros AR71XX/AR724X/AR913X based boards"
+	select BOOT_RAW
+	select CEVT_R4K
+	select CSRC_R4K
+	select DMA_NONCOHERENT
+	select IRQ_CPU
+	select SYS_HAS_CPU_MIPS32_R2
+	select SYS_HAS_EARLY_PRINTK
+	select SYS_SUPPORTS_32BIT_KERNEL
+	select SYS_SUPPORTS_BIG_ENDIAN
+	help
+	  Support for the Atheros AR71XX/AR724X/AR913X SoCs.
+
 config BCM47XX
 	bool "Broadcom BCM47XX based boards"
 	select CEVT_R4K
@@ -718,6 +732,7 @@ config CAVIUM_OCTEON_REFERENCE_BOARD
 endchoice
 
 source "arch/mips/alchemy/Kconfig"
+source "arch/mips/ath79/Kconfig"
 source "arch/mips/bcm63xx/Kconfig"
 source "arch/mips/jazz/Kconfig"
 source "arch/mips/jz4740/Kconfig"

arch/mips/ath79/Kconfig

@@ -0,0 +1,12 @@
+if ATH79
+
+config SOC_AR71XX
+	def_bool n
+
+config SOC_AR724X
+	def_bool n
+
+config SOC_AR913X
+	def_bool n
+
+endif

arch/mips/ath79/Makefile

@@ -0,0 +1,18 @@
+#
+# Makefile for the Atheros AR71XX/AR724X/AR913X specific parts of the kernel
+#
+# Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+# Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+#
+# 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.
+
+obj-y	:= prom.o setup.o irq.o common.o clock.o
+
+obj-$(CONFIG_EARLY_PRINTK)		+= early_printk.o
+
+#
+# Devices
+#
+obj-y					+= dev-common.o

arch/mips/ath79/Platform

@@ -0,0 +1,7 @@
+#
+# Atheros AR71xx/AR724x/AR913x
+#
+
+platform-$(CONFIG_ATH79)	+= ath79/
+cflags-$(CONFIG_ATH79)		+= -I$(srctree)/arch/mips/include/asm/mach-ath79
+load-$(CONFIG_ATH79)		= 0xffffffff80060000

arch/mips/ath79/clock.c

@@ -0,0 +1,183 @@
+/*
+ *  Atheros AR71XX/AR724X/AR913X common routines
+ *
+ *  Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
+ *
+ *  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/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include "common.h"
+
+#define AR71XX_BASE_FREQ	40000000
+#define AR724X_BASE_FREQ	5000000
+#define AR913X_BASE_FREQ	5000000
+
+struct clk {
+	unsigned long rate;
+};
+
+static struct clk ath79_ref_clk;
+static struct clk ath79_cpu_clk;
+static struct clk ath79_ddr_clk;
+static struct clk ath79_ahb_clk;
+static struct clk ath79_wdt_clk;
+static struct clk ath79_uart_clk;
+
+static void __init ar71xx_clocks_init(void)
+{
+	u32 pll;
+	u32 freq;
+	u32 div;
+
+	ath79_ref_clk.rate = AR71XX_BASE_FREQ;
+
+	pll = ath79_pll_rr(AR71XX_PLL_REG_CPU_CONFIG);
+
+	div = ((pll >> AR71XX_PLL_DIV_SHIFT) & AR71XX_PLL_DIV_MASK) + 1;
+	freq = div * ath79_ref_clk.rate;
+
+	div = ((pll >> AR71XX_CPU_DIV_SHIFT) & AR71XX_CPU_DIV_MASK) + 1;
+	ath79_cpu_clk.rate = freq / div;
+
+	div = ((pll >> AR71XX_DDR_DIV_SHIFT) & AR71XX_DDR_DIV_MASK) + 1;
+	ath79_ddr_clk.rate = freq / div;
+
+	div = (((pll >> AR71XX_AHB_DIV_SHIFT) & AR71XX_AHB_DIV_MASK) + 1) * 2;
+	ath79_ahb_clk.rate = ath79_cpu_clk.rate / div;
+
+	ath79_wdt_clk.rate = ath79_ahb_clk.rate;
+	ath79_uart_clk.rate = ath79_ahb_clk.rate;
+}
+
+static void __init ar724x_clocks_init(void)
+{
+	u32 pll;
+	u32 freq;
+	u32 div;
+
+	ath79_ref_clk.rate = AR724X_BASE_FREQ;
+	pll = ath79_pll_rr(AR724X_PLL_REG_CPU_CONFIG);
+
+	div = ((pll >> AR724X_PLL_DIV_SHIFT) & AR724X_PLL_DIV_MASK);
+	freq = div * ath79_ref_clk.rate;
+
+	div = ((pll >> AR724X_PLL_REF_DIV_SHIFT) & AR724X_PLL_REF_DIV_MASK);
+	freq *= div;
+
+	ath79_cpu_clk.rate = freq;
+
+	div = ((pll >> AR724X_DDR_DIV_SHIFT) & AR724X_DDR_DIV_MASK) + 1;
+	ath79_ddr_clk.rate = freq / div;
+
+	div = (((pll >> AR724X_AHB_DIV_SHIFT) & AR724X_AHB_DIV_MASK) + 1) * 2;
+	ath79_ahb_clk.rate = ath79_cpu_clk.rate / div;
+
+	ath79_wdt_clk.rate = ath79_ahb_clk.rate;
+	ath79_uart_clk.rate = ath79_ahb_clk.rate;
+}
+
+static void __init ar913x_clocks_init(void)
+{
+	u32 pll;
+	u32 freq;
+	u32 div;
+
+	ath79_ref_clk.rate = AR913X_BASE_FREQ;
+	pll = ath79_pll_rr(AR913X_PLL_REG_CPU_CONFIG);
+
+	div = ((pll >> AR913X_PLL_DIV_SHIFT) & AR913X_PLL_DIV_MASK);
+	freq = div * ath79_ref_clk.rate;
+
+	ath79_cpu_clk.rate = freq;
+
+	div = ((pll >> AR913X_DDR_DIV_SHIFT) & AR913X_DDR_DIV_MASK) + 1;
+	ath79_ddr_clk.rate = freq / div;
+
+	div = (((pll >> AR913X_AHB_DIV_SHIFT) & AR913X_AHB_DIV_MASK) + 1) * 2;
+	ath79_ahb_clk.rate = ath79_cpu_clk.rate / div;
+
+	ath79_wdt_clk.rate = ath79_ahb_clk.rate;
+	ath79_uart_clk.rate = ath79_ahb_clk.rate;
+}
+
+void __init ath79_clocks_init(void)
+{
+	if (soc_is_ar71xx())
+		ar71xx_clocks_init();
+	else if (soc_is_ar724x())
+		ar724x_clocks_init();
+	else if (soc_is_ar913x())
+		ar913x_clocks_init();
+	else
+		BUG();
+
+	pr_info("Clocks: CPU:%lu.%03luMHz, DDR:%lu.%03luMHz, AHB:%lu.%03luMHz, "
+		"Ref:%lu.%03luMHz",
+		ath79_cpu_clk.rate / 1000000,
+		(ath79_cpu_clk.rate / 1000) % 1000,
+		ath79_ddr_clk.rate / 1000000,
+		(ath79_ddr_clk.rate / 1000) % 1000,
+		ath79_ahb_clk.rate / 1000000,
+		(ath79_ahb_clk.rate / 1000) % 1000,
+		ath79_ref_clk.rate / 1000000,
+		(ath79_ref_clk.rate / 1000) % 1000);
+}
+
+/*
+ * Linux clock API
+ */
+struct clk *clk_get(struct device *dev, const char *id)
+{
+	if (!strcmp(id, "ref"))
+		return &ath79_ref_clk;
+
+	if (!strcmp(id, "cpu"))
+		return &ath79_cpu_clk;
+
+	if (!strcmp(id, "ddr"))
+		return &ath79_ddr_clk;
+
+	if (!strcmp(id, "ahb"))
+		return &ath79_ahb_clk;
+
+	if (!strcmp(id, "wdt"))
+		return &ath79_wdt_clk;
+
+	if (!strcmp(id, "uart"))
+		return &ath79_uart_clk;
+
+	return ERR_PTR(-ENOENT);
+}
+EXPORT_SYMBOL(clk_get);
+
+int clk_enable(struct clk *clk)
+{
+	return 0;
+}
+EXPORT_SYMBOL(clk_enable);
+
+void clk_disable(struct clk *clk)
+{
+}
+EXPORT_SYMBOL(clk_disable);
+
+unsigned long clk_get_rate(struct clk *clk)
+{
+	return clk->rate;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
+void clk_put(struct clk *clk)
+{
+}
+EXPORT_SYMBOL(clk_put);

arch/mips/ath79/common.c

@@ -0,0 +1,97 @@
+/*
+ *  Atheros AR71XX/AR724X/AR913X common routines
+ *
+ *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  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/module.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include "common.h"
+
+static DEFINE_SPINLOCK(ath79_device_reset_lock);
+
+u32 ath79_cpu_freq;
+EXPORT_SYMBOL_GPL(ath79_cpu_freq);
+
+u32 ath79_ahb_freq;
+EXPORT_SYMBOL_GPL(ath79_ahb_freq);
+
+u32 ath79_ddr_freq;
+EXPORT_SYMBOL_GPL(ath79_ddr_freq);
+
+enum ath79_soc_type ath79_soc;
+
+void __iomem *ath79_pll_base;
+void __iomem *ath79_reset_base;
+EXPORT_SYMBOL_GPL(ath79_reset_base);
+void __iomem *ath79_ddr_base;
+
+void ath79_ddr_wb_flush(u32 reg)
+{
+	void __iomem *flush_reg = ath79_ddr_base + reg;
+
+	/* Flush the DDR write buffer. */
+	__raw_writel(0x1, flush_reg);
+	while (__raw_readl(flush_reg) & 0x1)
+		;
+
+	/* It must be run twice. */
+	__raw_writel(0x1, flush_reg);
+	while (__raw_readl(flush_reg) & 0x1)
+		;
+}
+EXPORT_SYMBOL_GPL(ath79_ddr_wb_flush);
+
+void ath79_device_reset_set(u32 mask)
+{
+	unsigned long flags;
+	u32 reg;
+	u32 t;
+
+	if (soc_is_ar71xx())
+		reg = AR71XX_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar724x())
+		reg = AR724X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar913x())
+		reg = AR913X_RESET_REG_RESET_MODULE;
+	else
+		BUG();
+
+	spin_lock_irqsave(&ath79_device_reset_lock, flags);
+	t = ath79_reset_rr(reg);
+	ath79_reset_wr(reg, t | mask);
+	spin_unlock_irqrestore(&ath79_device_reset_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ath79_device_reset_set);
+
+void ath79_device_reset_clear(u32 mask)
+{
+	unsigned long flags;
+	u32 reg;
+	u32 t;
+
+	if (soc_is_ar71xx())
+		reg = AR71XX_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar724x())
+		reg = AR724X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar913x())
+		reg = AR913X_RESET_REG_RESET_MODULE;
+	else
+		BUG();
+
+	spin_lock_irqsave(&ath79_device_reset_lock, flags);
+	t = ath79_reset_rr(reg);
+	ath79_reset_wr(reg, t & ~mask);
+	spin_unlock_irqrestore(&ath79_device_reset_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ath79_device_reset_clear);

arch/mips/ath79/common.h

@@ -0,0 +1,26 @@
+/*
+ *  Atheros AR71XX/AR724X/AR913X common definitions
+ *
+ *  Copyright (C) 2008-2011 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.
+ */
+
+#ifndef __ATH79_COMMON_H
+#define __ATH79_COMMON_H
+
+#include <linux/types.h>
+#include <linux/init.h>
+
+#define ATH79_MEM_SIZE_MIN	(2 * 1024 * 1024)
+#define ATH79_MEM_SIZE_MAX	(128 * 1024 * 1024)
+
+void ath79_clocks_init(void);
+void ath79_ddr_wb_flush(unsigned int reg);
+
+#endif /* __ATH79_COMMON_H */