platform: Update Nuclei ux600 platform support

Changes are made to support our FPGA evaluation board,
it has DDR memory(0xA0000000-0xB0000000).

* Adapt the config.mk to match FPGA evaluation board DDR memory address
* Since the RISC-V CPU core frequency of FPGA might change, so we use the
  fixed TIMER frequency to measure the real CPU core frequency.
* And the UART baudrate has to set to 57600bps for Nuclei FPGA evaluation
  board when CPU core frequency is about 8MHz, otherwise the UART input
  will not work correctly.

Signed-off-by: Huaqi Fang <578567190@qq.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

platform/nuclei/ux600/config.mk

@@ -19,12 +19,12 @@ platform-runcmd = xl_spike \
   $(build_dir)/platform/nuclei/ux600/firmware/fw_payload.elf
 
 # Blobs to build
-FW_TEXT_START=0x80000000
+FW_TEXT_START=0xA0000000
 FW_DYNAMIC=y
 FW_JUMP=y
 
-FW_JUMP_ADDR=0x80200000
-FW_JUMP_FDT_ADDR=0x88000000
+FW_JUMP_ADDR=0xA0200000
+FW_JUMP_FDT_ADDR=0xA8000000
 FW_PAYLOAD=y
 FW_PAYLOAD_OFFSET=0x200000
-FW_PAYLOAD_FDT_ADDR=0x88000000
+FW_PAYLOAD_FDT_ADDR=0xA8000000

platform/nuclei/ux600/platform.c

@@ -23,11 +23,12 @@
 /* clang-format off */
 
 #define UX600_HART_COUNT		1
-
-#define UX600_SYS_CLK			1000000000
+#define UX600_TIMER_FREQ		32768
 
 /* Nuclei timer base address */
 #define UX600_NUCLEI_TIMER_ADDR		0x2000000
+#define UX600_NUCLEI_TIMER_MSFTRST_OFS	0xFF0
+#define UX600_NUCLEI_TIMER_MSFTRST_KEY	0x80000A5F
 /* The clint compatiable timer offset is 0x1000 against nuclei timer */
 #define UX600_CLINT_TIMER_ADDR		(UX600_NUCLEI_TIMER_ADDR + 0x1000)
 
@@ -39,9 +40,20 @@
 #define UX600_UART1_ADDR		0x10023000
 
 #define UX600_DEBUG_UART		UX600_UART0_ADDR
-#define UX600_UART_BAUDRATE		115200
+
+#ifndef UX600_UART_BAUDRATE
+#define UX600_UART_BAUDRATE		57600
+#endif
+
+#define UX600_GPIO_ADDR			0x10012000
+#define UX600_GPIO_IOF_EN_OFS		0x38
+#define UX600_GPIO_IOF_SEL_OFS		0x3C
+#define UX600_GPIO_IOF_UART0_MASK	0x00030000
+
+#define UX600_TIMER_VALUE()		readl((void *)UX600_NUCLEI_TIMER_ADDR)
 
 /* clang-format on */
+static u32 ux600_clk_freq = 8000000;
 
 static struct plic_data plic = {
 	.addr = UX600_PLIC_ADDR,
@@ -54,6 +66,60 @@ static struct clint_data clint = {
 	.hart_count = UX600_HART_COUNT,
 	.has_64bit_mmio = TRUE,
 };
+static u32 measure_cpu_freq(u32 n)
+{
+	u32 start_mtime, delta_mtime;
+	u32 mtime_freq = UX600_TIMER_FREQ;
+	u32 tmp = (u32)UX600_TIMER_VALUE();
+	u32 start_mcycle, delta_mcycle, freq;
+
+	/* Don't start measuring until we see an mtime tick */
+	do {
+		start_mtime = (u32)UX600_TIMER_VALUE();
+	} while (start_mtime == tmp);
+
+	start_mcycle = csr_read(mcycle);
+
+	do {
+		delta_mtime = (u32)UX600_TIMER_VALUE() - start_mtime;
+	} while (delta_mtime < n);
+
+	delta_mcycle = csr_read(mcycle) - start_mcycle;
+
+	freq = (delta_mcycle / delta_mtime) * mtime_freq
+		+ ((delta_mcycle % delta_mtime) * mtime_freq) / delta_mtime;
+
+	return freq;
+}
+
+static u32 ux600_get_clk_freq(void)
+{
+	u32 cpu_freq;
+
+	/* warm up */
+	measure_cpu_freq(1);
+	/* measure for real */
+	cpu_freq = measure_cpu_freq(100);
+
+	return cpu_freq;
+}
+
+static int ux600_early_init(bool cold_boot)
+{
+	u32 regval;
+
+	/* Measure CPU Frequency using Timer */
+	ux600_clk_freq = ux600_get_clk_freq();
+
+	/* Init GPIO UART pinmux */
+	regval = readl((void *)(UX600_GPIO_ADDR + UX600_GPIO_IOF_SEL_OFS)) &
+		 ~UX600_GPIO_IOF_UART0_MASK;
+	writel(regval, (void *)(UX600_GPIO_ADDR + UX600_GPIO_IOF_SEL_OFS));
+	regval = readl((void *)(UX600_GPIO_ADDR + UX600_GPIO_IOF_EN_OFS)) |
+		UX600_GPIO_IOF_UART0_MASK;
+	writel(regval, (void *)(UX600_GPIO_ADDR + UX600_GPIO_IOF_EN_OFS));
+	return 0;
+}
 
 static void ux600_modify_dt(void *fdt)
 {
@@ -75,7 +141,7 @@ static int ux600_final_init(bool cold_boot)
 
 static int ux600_console_init(void)
 {
-	return sifive_uart_init(UX600_DEBUG_UART, UX600_SYS_CLK,
+	return sifive_uart_init(UX600_DEBUG_UART, ux600_clk_freq,
 				UX600_UART_BAUDRATE);
 }
 
@@ -122,11 +188,15 @@ static int ux600_timer_init(bool cold_boot)
 
 static int ux600_system_reset(u32 type)
 {
-	/* For now nothing to do. */
+	/* Reset system using MSFTRST register in Nuclei Timer. */
+	writel(UX600_NUCLEI_TIMER_MSFTRST_KEY, (void *)(UX600_NUCLEI_TIMER_ADDR
+					+ UX600_NUCLEI_TIMER_MSFTRST_OFS));
+	while(1);
 	return 0;
 }
 
 const struct sbi_platform_operations platform_ops = {
+	.early_init		= ux600_early_init,
 	.final_init		= ux600_final_init,
 	.console_putc		= sifive_uart_putc,
 	.console_getc		= sifive_uart_getc,