ARM: ixp4xx: Add device tree boot support

This adds a minimal support for booting IXP4xx systems
from device tree.

We have to add hacks to the QMGR, NPE and notably also
ethernet and watchdog drivers so that they don't crash
the platform: these drivers are unconditionally starting
to grab regions of statically remapped IO space with no
concern of the device model or other platforms.

We will go in and properly fix these drivers as we go
along but for now this hack gets us to a place where we
can start working on proper device tree support for these
platforms.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 60 insertions, 0 deletions

diff --git a/arch/arm/mach-ixp4xx/ixp4xx-of.c b/arch/arm/mach-ixp4xx/ixp4xx-of.c
new file mode 100644
index 000000000000..7449b8319c8a
--- /dev/null
+++ b/arch/arm/mach-ixp4xx/ixp4xx-of.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IXP4xx Device Tree boot support
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include <mach/hardware.h>
+#include <mach/ixp4xx-regs.h>
+
+static struct map_desc ixp4xx_of_io_desc[] __initdata = {
+	/*
+	 * This is needed for runtime system configuration checks,
+	 * such as reading if hardware so-and-so is present. This
+	 * could eventually be converted into a syscon once all boards
+	 * are converted to device tree.
+	 */
+	{
+		.virtual = IXP4XX_EXP_CFG_BASE_VIRT,
+		.pfn = __phys_to_pfn(IXP4XX_EXP_CFG_BASE_PHYS),
+		.length = SZ_4K,
+		.type = MT_DEVICE,
+	},
+#ifdef CONFIG_DEBUG_UART_8250
+	/* This is needed for LL-debug/earlyprintk/debug-macro.S */
+	{
+		.virtual = CONFIG_DEBUG_UART_VIRT,
+		.pfn = __phys_to_pfn(CONFIG_DEBUG_UART_PHYS),
+		.length = SZ_4K,
+		.type = MT_DEVICE,
+	},
+#endif
+};
+
+static void __init ixp4xx_of_map_io(void)
+{
+	iotable_init(ixp4xx_of_io_desc, ARRAY_SIZE(ixp4xx_of_io_desc));
+}
+
+/*
+ * We handle 4 differen SoC families. These compatible strings are enough
+ * to provide the core so that different boards can add their more detailed
+ * specifics.
+ */
+static const char *ixp4xx_of_board_compat[] = {
+	"intel,ixp42x",
+	"intel,ixp43x",
+	"intel,ixp45x",
+	"intel,ixp46x",
+	NULL,
+};
+
+DT_MACHINE_START(IXP4XX_DT, "IXP4xx (Device Tree)")
+	.map_io		= ixp4xx_of_map_io,
+	.dt_compat	= ixp4xx_of_board_compat,
+MACHINE_END