nios2: convert nios2 cpu to driver model

Convert nios2 cpu to driver model. The cpu parameters are
extracted from device tree and saved to global data structure.
We will use them to replace the custom_fpga.h .

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/Kconfig

@@ -64,6 +64,9 @@ config NIOS2
 	select HAVE_GENERIC_BOARD
 	select SYS_GENERIC_BOARD
 	select SUPPORT_OF_CONTROL
+	select OF_CONTROL
+	select DM
+	select CPU
 
 config OPENRISC
 	bool "OpenRISC architecture"

arch/nios2/cpu/cpu.c

@@ -6,7 +6,9 @@
  */
 
 #include <common.h>
-#include <asm/nios2.h>
+#include <cpu.h>
+#include <dm.h>
+#include <errno.h>
 #include <asm/cache.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -51,10 +53,92 @@ void dcache_disable(void)
 	flush_dcache(CONFIG_SYS_DCACHE_SIZE, CONFIG_SYS_DCACHELINE_SIZE);
 }
 
-int arch_cpu_init(void)
+int arch_cpu_init_dm(void)
 {
-	gd->cpu_clk = CONFIG_SYS_CLK_FREQ;
+	struct udevice *dev;
+	int ret;
+
+	ret = uclass_first_device(UCLASS_CPU, &dev);
+	if (ret)
+		return ret;
+	if (!dev)
+		return -ENODEV;
+
 	gd->ram_size = CONFIG_SYS_SDRAM_SIZE;
 
 	return 0;
 }
+
+static int altera_nios2_get_desc(struct udevice *dev, char *buf, int size)
+{
+	const char *cpu_name = "Nios-II";
+
+	if (size < strlen(cpu_name))
+		return -ENOSPC;
+	strcpy(buf, cpu_name);
+
+	return 0;
+}
+
+static int altera_nios2_get_info(struct udevice *dev, struct cpu_info *info)
+{
+	info->cpu_freq = gd->cpu_clk;
+	info->features = (1 << CPU_FEAT_L1_CACHE) |
+		(gd->arch.has_mmu ? (1 << CPU_FEAT_MMU) : 0);
+
+	return 0;
+}
+
+static int altera_nios2_get_count(struct udevice *dev)
+{
+	return 1;
+}
+
+static int altera_nios2_probe(struct udevice *dev)
+{
+	const void *blob = gd->fdt_blob;
+	int node = dev->of_offset;
+
+	gd->cpu_clk = fdtdec_get_int(blob, node,
+		"clock-frequency", 0);
+	gd->arch.dcache_line_size = fdtdec_get_int(blob, node,
+		"dcache-line-size", 0);
+	gd->arch.icache_line_size = fdtdec_get_int(blob, node,
+		"icache-line-size", 0);
+	gd->arch.dcache_size = fdtdec_get_int(blob, node,
+		"dcache-size", 0);
+	gd->arch.icache_size = fdtdec_get_int(blob, node,
+		"icache-size", 0);
+	gd->arch.reset_addr = fdtdec_get_int(blob, node,
+		"altr,reset-addr", 0);
+	gd->arch.exception_addr = fdtdec_get_int(blob, node,
+		"altr,exception-addr", 0);
+	gd->arch.has_initda = fdtdec_get_int(blob, node,
+		"altr,has-initda", 0);
+	gd->arch.has_mmu = fdtdec_get_int(blob, node,
+		"altr,has-mmu", 0);
+	gd->arch.io_region_base = gd->arch.has_mmu ? 0xe0000000 : 0x8000000;
+
+	return 0;
+}
+
+static const struct cpu_ops altera_nios2_ops = {
+	.get_desc	= altera_nios2_get_desc,
+	.get_info	= altera_nios2_get_info,
+	.get_count	= altera_nios2_get_count,
+};
+
+static const struct udevice_id altera_nios2_ids[] = {
+	{ .compatible = "altr,nios2-1.0" },
+	{ .compatible = "altr,nios2-1.1" },
+	{ }
+};
+
+U_BOOT_DRIVER(altera_nios2) = {
+	.name		= "altera_nios2",
+	.id		= UCLASS_CPU,
+	.of_match	= altera_nios2_ids,
+	.probe		= altera_nios2_probe,
+	.ops		= &altera_nios2_ops,
+	.flags		= DM_FLAG_PRE_RELOC,
+};

arch/nios2/include/asm/global_data.h

@@ -9,6 +9,15 @@
 
 /* Architecture-specific global data */
 struct arch_global_data {
+	u32 dcache_line_size;
+	u32 icache_line_size;
+	u32 dcache_size;
+	u32 icache_size;
+	u32 reset_addr;
+	u32 exception_addr;
+	int has_initda;
+	int has_mmu;
+	u32 io_region_base;
 };
 
 #include <asm-generic/global_data.h>

configs/nios2-generic_defconfig

@@ -4,6 +4,7 @@ CONFIG_DM_GPIO=y
 CONFIG_TARGET_NIOS2_GENERIC=y
 CONFIG_DEFAULT_DEVICE_TREE="3c120_devboard"
 CONFIG_HUSH_PARSER=y
+CONFIG_CMD_CPU=y
 # CONFIG_CMD_BOOTD is not set
 # CONFIG_CMD_IMLS is not set
 # CONFIG_CMD_XIMG is not set
@@ -13,9 +14,7 @@ CONFIG_HUSH_PARSER=y
 CONFIG_CMD_DHCP=y
 # CONFIG_CMD_NFS is not set
 CONFIG_CMD_PING=y
-CONFIG_OF_CONTROL=y
 CONFIG_NET_RANDOM_ETHADDR=y
-CONFIG_DM=y
 CONFIG_ALTERA_PIO=y
 CONFIG_ALTERA_JTAG_UART=y
 CONFIG_ALTERA_JTAG_UART_BYPASS=y

doc/device-tree-bindings/cpu/nios2.txt

@@ -0,0 +1,54 @@
+* Nios II Processor Binding
+
+This binding specifies what properties available in the device tree
+representation of a Nios II Processor Core.
+
+Users can use sopc2dts tool for generating device tree sources (dts) from a
+Qsys system. See more detail in: http://www.alterawiki.com/wiki/Sopc2dts
+
+Required properties:
+
+- compatible: Compatible property value should be "altr,nios2-1.0" or
+  "altr,nios2-1.1".
+- reg: Contains CPU index.
+- clock-frequency: Contains the clock frequency for CPU, in Hz.
+- dcache-line-size: Contains data cache line size.
+- icache-line-size: Contains instruction line size.
+- dcache-size: Contains data cache size.
+- icache-size: Contains instruction cache size.
+- altr,reset-addr: Specifies CPU reset address
+- altr,exception-addr: Specifies CPU exception address
+
+Optional properties:
+- altr,has-initda: Specifies CPU support initda instruction, should be 1.
+- altr,has-mmu: Specifies CPU support MMU support.
+- altr,has-mul: Specifies CPU hardware multipy support.
+- altr,has-div: Specifies CPU hardware divide support
+- altr,implementation: Nios II core implementation, this should be "fast";
+
+Example:
+
+cpu@0x0 {
+	device_type = "cpu";
+	compatible = "altr,nios2-1.0";
+	reg = <0>;
+	interrupt-controller;
+	#interrupt-cells = <1>;
+	clock-frequency = <125000000>;
+	dcache-line-size = <32>;
+	icache-line-size = <32>;
+	dcache-size = <32768>;
+	icache-size = <32768>;
+	altr,implementation = "fast";
+	altr,pid-num-bits = <8>;
+	altr,tlb-num-ways = <16>;
+	altr,tlb-num-entries = <128>;
+	altr,tlb-ptr-sz = <7>;
+	altr,has-div = <1>;
+	altr,has-mul = <1>;
+	altr,reset-addr = <0xc2800000>;
+	altr,fast-tlb-miss-addr = <0xc7fff400>;
+	altr,exception-addr = <0xd0000020>;
+	altr,has-initda = <1>;
+	altr,has-mmu = <1>;
+};