jz4760: Explicitly disable UARTs at startup

(Bootloader uses UART1, and leaves it running when it hands it off to us)

Change-Id: Icde1d713574582f18e9f91b5c95f3917fe324b74

firmware/target/mips/ingenic_jz47xx/debug-jz4760.c

@@ -138,6 +138,8 @@ bool dbg_ports(void)
     return false;
 }
 
+extern uint32_t irqstackend,irqstackbegin;
+
 bool dbg_hw_info(void)
 {
     int btn = 0;
@@ -151,6 +153,12 @@ bool dbg_hw_info(void)
     {
         lcd_clear_display();
         line = 0;
+
+        uint32_t *ptr = &irqstackbegin;
+        for ( ; ptr < &irqstackend && *ptr == 0xDEADBEEF; ptr++) {}
+
+        lcd_putsf(0, line++, "IRQ stack max: %d", (uint32_t)&irqstackend - (uint32_t)ptr);
+
         display_clocks();
         display_enabled_clocks();
 #ifdef HAVE_TOUCHSCREEN
@@ -169,8 +177,7 @@ bool dbg_hw_info(void)
     return true;
 }
 
-#define CFG_UART_BASE           UART1_BASE      /* Base of the UART channel */
-
+#ifdef WITH_SERIAL
 void serial_putc (const char c)
 {
         volatile u8 *uart_lsr = (volatile u8 *)(CFG_UART_BASE + OFF_LSR);
@@ -271,3 +278,4 @@ void serial_dump_data(unsigned char* data, int len)
 
         serial_putc( '\n' );
 }
+#endif

firmware/target/mips/ingenic_jz47xx/system-jz4760.c

@@ -29,6 +29,9 @@
 #include "power.h"
 
 //#define USE_HW_UDELAY  // This is BROKEN.
+#ifdef BOOTLOADER
+#define WITH_SERIAL
+#endif
 
 static int irq;
 static void UIRQ(void)
@@ -535,6 +538,7 @@ void pll1_disable(void)
     REG_CPM_CPPCR1 &= ~CPPCR1_PLL1EN;
 }
 
+#ifdef WITH_SERIAL
 static void serial_setbrg(void)
 {
     volatile u8 *uart_lcr = (volatile u8 *)(CFG_UART_BASE + OFF_LCR);
@@ -589,6 +593,7 @@ int serial_preinit(void)
 
     return 0;
 }
+#endif
 
 #ifndef HAVE_ADJUSTABLE_CPU_FREQ
 #define cpu_frequency CPU_FREQ
@@ -698,7 +703,14 @@ void ICODE_ATTR system_main(void)
     pll0_init(CPUFREQ_DEFAULT); // PLL0 drives everything but audio
     pll1_disable();             // Leave PLL1 disabled until audio needs it
 
+    /* Make sure UARTs are off */
+    __cpm_stop_uart0();
+    __cpm_stop_uart1();
+    __cpm_stop_uart2();
+#ifdef WITH_SERIAL
     serial_preinit();
+#endif
+
     usb_preinit();
     dma_preinit();
 

firmware/target/mips/ingenic_jz47xx/system-target.h

@@ -32,6 +32,8 @@
 #define CACHE_LINE_SIZE  32
 #include "mmu-mips.h"
 
+#define CFG_UART_BASE    UART1_BASE      /* Base of the UART channel */
+
 /* no optimized byteswap functions implemented for mips, yet */
 #define NEED_GENERIC_BYTESWAPS