rp2/clocks_extra: Update runtime_clocks_init based on new pico-sdk.

Signed-off-by: Damien George <damien@micropython.org>

ports/rp2/CMakeLists.txt

@@ -181,6 +181,7 @@ set(PICO_SDK_COMPONENTS
     cmsis_core
     hardware_adc
     hardware_base
+    hardware_boot_lock
     hardware_clocks
     hardware_dma
     hardware_flash
@@ -487,7 +488,7 @@ target_compile_options(${MICROPY_TARGET} PRIVATE
 target_link_options(${MICROPY_TARGET} PRIVATE
     -Wl,--defsym=__micropy_c_heap_size__=${MICROPY_C_HEAP_SIZE}
     -Wl,--wrap=dcd_event_handler
-    -Wl,--wrap=clocks_init
+    -Wl,--wrap=runtime_init_clocks
 )
 
 # Apply optimisations to performance-critical source code.

ports/rp2/clocks_extra.c

@@ -13,22 +13,36 @@
 #include "hardware/xosc.h"
 #include "hardware/irq.h"
 #include "hardware/gpio.h"
+#include "hardware/ticks.h"
 
+#if PICO_RP2040
+// The RTC clock frequency is 48MHz divided by power of 2 (to ensure an integer
+// division ratio will be used in the clocks block).  A divisor of 1024 generates
+// an RTC clock tick of 46875Hz.  This frequency is relatively close to the
+// customary 32 or 32.768kHz 'slow clock' crystals and provides good timing resolution.
 #define RTC_CLOCK_FREQ_HZ       (USB_CLK_KHZ * KHZ / 1024)
+#endif
 
-// Wrap the SDK's clocks_init() function to save code size
-void __wrap_clocks_init(void) {
-    clocks_init_optional_usb(true);
+static void start_all_ticks(void) {
+    uint32_t cycles = clock_get_hz(clk_ref) / MHZ;
+    // Note RP2040 has a single tick generator in the watchdog which serves
+    // watchdog, system timer and M0+ SysTick; The tick generator is clocked from clk_ref
+    // but is now adapted by the hardware_ticks library for compatibility with RP2350
+    // npte: hardware_ticks library now provides an adapter for RP2040
+
+    for (int i = 0; i < (int)TICK_COUNT; ++i) {
+        tick_start((tick_gen_num_t)i, cycles);
+    }
 }
 
-// Copy of clocks_init() from pico-sdk, with USB
+// Wrap the SDK's clocks_init() function to save code size
+void __wrap_runtime_init_clocks(void) {
+    runtime_init_clocks_optional_usb(true);
+}
+
+// Copy of runtime_init_clocks() from pico-sdk, with USB
 // PLL and clock init made optional (for light sleep wakeup).
-void clocks_init_optional_usb(bool init_usb) {
-    // Start tick in watchdog, the argument is in 'cycles per microsecond' i.e. MHz
-    watchdog_start_tick(XOSC_KHZ / KHZ);
-
-    // Modification: removed FPGA check here
-
+void runtime_init_clocks_optional_usb(bool init_usb) {
     // Disable resus that may be enabled from previous software
     clocks_hw->resus.ctrl = 0;
 
@@ -46,14 +60,26 @@ void clocks_init_optional_usb(bool init_usb) {
     }
 
     /// \tag::pll_init[]
-    pll_init(pll_sys, PLL_COMMON_REFDIV, PLL_SYS_VCO_FREQ_KHZ * KHZ, PLL_SYS_POSTDIV1, PLL_SYS_POSTDIV2);
+    pll_init(pll_sys, PLL_COMMON_REFDIV, PLL_SYS_VCO_FREQ_HZ, PLL_SYS_POSTDIV1, PLL_SYS_POSTDIV2);
     if (init_usb) {
-        pll_init(pll_usb, PLL_COMMON_REFDIV, PLL_USB_VCO_FREQ_KHZ * KHZ, PLL_USB_POSTDIV1, PLL_USB_POSTDIV2);
+        pll_init(pll_usb, PLL_COMMON_REFDIV, PLL_USB_VCO_FREQ_HZ, PLL_USB_POSTDIV1, PLL_USB_POSTDIV2);
     }
     /// \end::pll_init[]
 
     // Configure clocks
-    // CLK_REF = XOSC (usually) 12MHz / 1 = 12MHz
+
+    // todo amy, what is this N1,2,4 meant to mean?
+    // RP2040 CLK_REF = XOSC (usually) 12MHz / 1 = 12MHz
+    // RP2350 CLK_REF = XOSC (XOSC_MHZ) / N (1,2,4) = 12MHz
+
+    // clk_ref aux select is 0 because:
+    //
+    // - RP2040: no aux mux on clk_ref, so this field is don't-care.
+    //
+    // - RP2350: there is an aux mux, but we are selecting one of the
+    //   non-aux inputs to the glitchless mux, so the aux select doesn't
+    //   matter. The value of 0 here happens to be the sys PLL.
+
     clock_configure(clk_ref,
         CLOCKS_CLK_REF_CTRL_SRC_VALUE_XOSC_CLKSRC,
         0,             // No aux mux
@@ -85,18 +111,32 @@ void clocks_init_optional_usb(bool init_usb) {
         USB_CLK_KHZ * KHZ,
         USB_CLK_KHZ * KHZ);
 
+    #if HAS_RP2040_RTC
     // CLK RTC = PLL USB 48MHz / 1024 = 46875Hz
     clock_configure(clk_rtc,
         0,             // No GLMUX
         CLOCKS_CLK_RTC_CTRL_AUXSRC_VALUE_CLKSRC_PLL_USB,
         USB_CLK_KHZ * KHZ,
         RTC_CLOCK_FREQ_HZ);
+    #endif
 
-    // CLK PERI = clk_sys. Used as reference clock for Peripherals. No dividers so just select and enable
-    // Normally choose clk_sys or clk_usb
+    // CLK PERI = clk_sys. Used as reference clock for UART and SPI serial.
     clock_configure(clk_peri,
         0,
         CLOCKS_CLK_PERI_CTRL_AUXSRC_VALUE_CLK_SYS,
         SYS_CLK_KHZ * KHZ,
         SYS_CLK_KHZ * KHZ);
+
+    #if PICO_RP2350
+    // CLK_HSTX = clk_sys. Transmit bit clock for the HSTX peripheral.
+    clock_configure(clk_hstx,
+        0,
+        CLOCKS_CLK_HSTX_CTRL_AUXSRC_VALUE_CLK_SYS,
+        SYS_CLK_KHZ * KHZ,
+        SYS_CLK_KHZ * KHZ);
+    #endif
+
+    // Finally, all clocks are configured so start the ticks
+    // The ticks use clk_ref so now that is configured we can start them
+    start_all_ticks();
 }

ports/rp2/clocks_extra.h

@@ -28,6 +28,6 @@
 
 #include "hardware/clocks.h"
 
-void clocks_init_optional_usb(bool init_usb);
+void runtime_init_clocks_optional_usb(bool init_usb);
 
 #endif // MICROPY_INCLUDED_RP2_CLOCKS_EXTRA_H

ports/rp2/modmachine.c

@@ -259,7 +259,7 @@ static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     rosc_hw->ctrl = ROSC_CTRL_ENABLE_VALUE_ENABLE << ROSC_CTRL_ENABLE_LSB;
 
     // Bring back all clocks.
-    clocks_init_optional_usb(disable_usb);
+    runtime_init_clocks_optional_usb(disable_usb);
     MICROPY_END_ATOMIC_SECTION(my_interrupts);
 }