[rp20xx] quick and dirty early init using pico-sdk driver code

- pull in headers for essential modules
- init clocks, gpios, uart0 out of platform_early_init
- wire up debug getc/putc to uart0
- comment out "native" uart impl

platform/rp20xx/debug.c

@@ -1,31 +1,25 @@
-// Copyright (c) 2012 Travis Geiselbrecht
+// Copyright (c) 2020 Brian Swetland
 //
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT
 
-#include <stdarg.h>
-#include <lk/reg.h>
-#include <lk/debug.h>
-#include <stdio.h>
-#include <kernel/thread.h>
 #include <platform/debug.h>
-#include <arch/ops.h>
-#include <dev/uart.h>
-#include <target/debugconfig.h>
-#include <arch/arm/cm.h>
+
+#include <hardware/uart.h>
+
+#include <stdio.h>
 
 void platform_dputc(char c) {
     if (c == '\n')
-        uart_putc(DEBUG_UART, '\r');
-    uart_putc(DEBUG_UART, c);
+        uart_putc(uart0, '\r');
+    uart_putc(uart0, c);
 }
 
 int platform_dgetc(char *c, bool wait) {
-    int ret = uart_getc(DEBUG_UART, wait);
-    if (ret == -1)
+    if (!wait && !uart_is_readable(uart0))
         return -1;
-    *c = ret;
+    *c = uart_getc(uart0);
     return 0;
 }
 

platform/rp20xx/init.c

@@ -7,9 +7,23 @@
 #include <platform.h>
 #include <arch/arm/cm.h>
 
+#include <hardware/clocks.h>
+#include <hardware/gpio.h>
+#include <hardware/uart.h>
+#include <hardware/resets.h>
+
 extern void* vectab;
 
 void platform_early_init(void) {
+    clocks_init();
+
+    unreset_block_wait(RESETS_RESET_BITS);
+
+    uart_init(uart0, 1000000);
+    gpio_set_function(0, GPIO_FUNC_UART);
+    gpio_set_function(1, GPIO_FUNC_UART);
+    uart_puts(uart0, "Hello World!\n");
+
     // arch/arm/arm-m/arch.c does this but only for M3 and above...
     SCB->VTOR = (uint32_t) &vectab;
 
@@ -18,3 +32,8 @@ void platform_early_init(void) {
 
 void platform_init(void) {
 }
+
+
+bool running_on_fpga(void) {
+	return false;
+}

platform/rp20xx/rules.mk

@@ -13,6 +13,7 @@ ARM_CPU := cortex-m0plus
 
 GLOBAL_DEFINES += \
 	MEMSIZE=$(MEMSIZE) \
+	PICO_ON_DEVICE=1 \
 	PICO_NO_BINARY_INFO=1
 
 MODULE_SRCS += \
@@ -22,6 +23,32 @@ MODULE_SRCS += \
 	$(LOCAL_DIR)/uart.c \
 	$(LOCAL_DIR)/vectab.c
 
+MODULE_SRCS += \
+	external/platform/pico/rp2_common/hardware_clocks/clocks.c \
+	external/platform/pico/rp2_common/hardware_gpio/gpio.c \
+	external/platform/pico/rp2_common/hardware_pll/pll.c \
+	external/platform/pico/rp2_common/hardware_uart/uart.c \
+	external/platform/pico/rp2_common/hardware_watchdog/watchdog.c \
+	external/platform/pico/rp2_common/hardware_xosc/xosc.c
+
+GLOBAL_INCLUDES += \
+	external/platform/pico/common/pico_base/include \
+	external/platform/pico/common/pico_binary_info/include \
+	external/platform/pico/rp2040/hardware_regs/include \
+	external/platform/pico/rp2040/hardware_structs/include \
+	external/platform/pico/rp2_common/pico_platform/include \
+	external/platform/pico/rp2_common/hardware_base/include \
+	external/platform/pico/rp2_common/hardware_clocks/include \
+	external/platform/pico/rp2_common/hardware_gpio/include \
+	external/platform/pico/rp2_common/hardware_irq/include \
+	external/platform/pico/rp2_common/hardware_pll/include \
+	external/platform/pico/rp2_common/hardware_sync/include \
+	external/platform/pico/rp2_common/hardware_resets/include \
+	external/platform/pico/rp2_common/hardware_timer/include \
+	external/platform/pico/rp2_common/hardware_uart/include \
+	external/platform/pico/rp2_common/hardware_watchdog/include \
+	external/platform/pico/rp2_common/hardware_xosc/include
+
 # use a two segment memory layout, where all of the read-only sections
 # of the binary reside in rom, and the read/write are in memory. The
 # ROMBASE, MEMBASE, and MEMSIZE make variables are required to be set

platform/rp20xx/uart.c

@@ -7,6 +7,7 @@
 #include <lk/reg.h>
 #include <lib/cbuf.h>
 
+#if 0
 void uart_init_early(void) {
 	for (;;) ;
 }
@@ -28,3 +29,4 @@ void uart_flush_rx(int port) {}
 
 void uart_init_port(int port, uint baud) {}
 
+#endif