Full UART support for RPI

This adds PL011 UART support which is more plentiful.

It also:
* Fixes PI4 build by including .dtb files on the SD card.
* Enables the activity LED as the status LED on PI4 and CM4 I/O.
* Adds that LED as board.LED.

Fixes #5650 and progress on #5629

main.c

@@ -56,6 +56,7 @@
 #include "supervisor/shared/safe_mode.h"
 #include "supervisor/shared/stack.h"
 #include "supervisor/shared/status_leds.h"
+#include "supervisor/shared/tick.h"
 #include "supervisor/shared/traceback.h"
 #include "supervisor/shared/translate.h"
 #include "supervisor/shared/workflow.h"

ports/broadcom/Makefile

@@ -166,7 +166,7 @@ $(BUILD)/firmware.disk.img.zip: $(BUILD)/kernel8.img
 	$(Q)parted -s $(BUILD)/circuitpython-disk.img mkpart primary fat32 0% 100%
 	$(Q)mkfs.fat -F 32 -n BOOT --offset=2048 $(BUILD)/circuitpython-disk.img
 
-	$(Q)mcopy -i $(BUILD)/circuitpython-disk.img@@1M config.txt firmware/bootcode.bin firmware/fixup* firmware/start* ::
+	$(Q)mcopy -i $(BUILD)/circuitpython-disk.img@@1M config.txt firmware/bootcode.bin firmware/fixup* firmware/start* firmware/*.dtb ::
 	$(Q)mcopy -i $(BUILD)/circuitpython-disk.img@@1M $(BUILD)/kernel8.img ::
 	$(Q)zip $@ $(BUILD)/circuitpython-disk.img
 	$(Q)rm $(BUILD)/circuitpython-disk.img

ports/broadcom/boards/raspberrypi_cm4io/mpconfigboard.h

@@ -2,3 +2,5 @@
 
 #define DEFAULT_I2C_BUS_SCL         (&pin_GPIO3)
 #define DEFAULT_I2C_BUS_SDA         (&pin_GPIO2)
+
+#define MICROPY_HW_LED_STATUS       (&pin_GPIO42)

ports/broadcom/boards/raspberrypi_cm4io/pins.c

@@ -57,6 +57,8 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_D26), MP_ROM_PTR(&pin_GPIO26) },
     { MP_ROM_QSTR(MP_QSTR_D27), MP_ROM_PTR(&pin_GPIO27) },
 
+    { MP_ROM_QSTR(MP_QSTR_LED), MP_ROM_PTR(&pin_GPIO42) },
+
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_DISPLAY), MP_ROM_PTR(&displays[0].display)},
 };

ports/broadcom/boards/raspberrypi_pi4b/mpconfigboard.h

@@ -2,3 +2,5 @@
 
 #define DEFAULT_I2C_BUS_SCL         (&pin_GPIO3)
 #define DEFAULT_I2C_BUS_SDA         (&pin_GPIO2)
+
+#define MICROPY_HW_LED_STATUS       (&pin_GPIO42)

ports/broadcom/boards/raspberrypi_pi4b/mpconfigboard.mk

@@ -3,4 +3,4 @@ USB_PID = 0xF001
 USB_PRODUCT = "Raspberry Pi 4B"
 USB_MANUFACTURER = "Raspberry Pi"
 
-CHIP_VARIANT = bcm2711
+CHIP_VARIANT = "bcm2711"

ports/broadcom/boards/raspberrypi_pi4b/pins.c

@@ -57,6 +57,8 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_D26), MP_ROM_PTR(&pin_GPIO26) },
     { MP_ROM_QSTR(MP_QSTR_D27), MP_ROM_PTR(&pin_GPIO27) },
 
+    { MP_ROM_QSTR(MP_QSTR_LED), MP_ROM_PTR(&pin_GPIO42) },
+
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_DISPLAY), MP_ROM_PTR(&displays[0].display)},
 };

ports/broadcom/common-hal/busio/I2C.c

@@ -72,7 +72,8 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
     uint8_t sda_alt = 0;
     for (scl_alt = 0; scl_alt < 6; scl_alt++) {
         if (scl->functions[scl_alt].type != PIN_FUNCTION_I2C ||
-            i2c_in_use[scl->functions[scl_alt].index]) {
+            i2c_in_use[scl->functions[scl_alt].index] ||
+            scl->functions[scl_alt].function != I2C_FUNCTION_SCL) {
             continue;
         }
         for (sda_alt = 0; sda_alt < 6; sda_alt++) {

ports/broadcom/common-hal/busio/UART.c

@@ -41,7 +41,14 @@
 
 #define NO_PIN 0xff
 
-#define UART_INST(uart) (((uart) ? uart1 : uart0))
+// UART1 is a different peripheral than the rest so it is hardcoded below.
+#if BCM_VERSION == 2711
+#define NUM_UART (6)
+STATIC ARM_UART_PL011_Type *uart[NUM_UART] = {UART0, NULL, UART2, UART3, UART4, UART5};
+#else
+#define NUM_UART (2)
+STATIC ARM_UART_PL011_Type *uart[NUM_UART] = {UART0, NULL};
+#endif
 
 typedef enum {
     STATUS_FREE = 0,
@@ -49,29 +56,62 @@ typedef enum {
     STATUS_NEVER_RESET
 } uart_status_t;
 
-// The Broadcom chips have two different types of UARTs. UART1 is the "mini-UART"
+static uart_status_t uart_status[NUM_UART];
-// that is most available so we've implemented it first. The ARM PL011 UART
+static busio_uart_obj_t *active_uart[NUM_UART];
-// support will be added later. We set NUM_UARTS to 2 here so that we can match
-// the indexing even though UART0 isn't supported yet. We currently use this
-// UART for debugging so we don't support user use of UART yet.
-#define NUM_UARTS 2
-
-static uart_status_t uart_status[NUM_UARTS];
 
 void reset_uart(void) {
-    for (uint8_t num = 0; num < NUM_UARTS; num++) {
+    bool any_pl011_active = false;
+    for (uint8_t num = 0; num < NUM_UART; num++) {
         if (uart_status[num] == STATUS_BUSY) {
+            if (num == 1) {
+                UART1->IER_b.DATA_READY = false;
+                UART1->CNTL = 0;
+                COMPLETE_MEMORY_READS;
+                AUX->ENABLES_b.UART_1 = false;
+            } else {
+                ARM_UART_PL011_Type *pl011 = uart[num];
+                pl011->CR = 0;
+            }
+            active_uart[num] = NULL;
             uart_status[num] = STATUS_FREE;
+        } else {
+            any_pl011_active = any_pl011_active || (num != 1 && uart_status[num] == STATUS_NEVER_RESET);
+        }
+    }
+    if (!any_pl011_active) {
+        BP_DisableIRQ(UART_IRQn);
+    }
+    COMPLETE_MEMORY_READS;
+    if (AUX->ENABLES == 0) {
+        BP_DisableIRQ(AUX_IRQn);
+    }
+}
+
+STATIC void fetch_all_from_fifo(busio_uart_obj_t *self) {
+    if (self->uart_id == 1) {
+        while (UART1->STAT_b.DATA_READY && ringbuf_num_empty(&self->ringbuf) > 0) {
+            int c = UART1->IO_b.DATA;
+            if (self->sigint_enabled && c == mp_interrupt_char) {
+                mp_sched_keyboard_interrupt();
+                continue;
+            }
+            ringbuf_put(&self->ringbuf, c);
+        }
+    } else {
+        ARM_UART_PL011_Type *pl011 = uart[self->uart_id];
+        while (!pl011->FR_b.RXFE && ringbuf_num_empty(&self->ringbuf) > 0) {
+            int c = pl011->DR_b.DATA;
+            if (self->sigint_enabled && c == mp_interrupt_char) {
+                mp_sched_keyboard_interrupt();
+                continue;
+            }
+            ringbuf_put(&self->ringbuf, c);
         }
     }
 }
 
-static busio_uart_obj_t *active_uarts[NUM_UARTS];
-
 void UART1_IRQHandler(void) {
-    while (UART1->STAT_b.DATA_READY && ringbuf_num_empty(&active_uarts[1]->ringbuf) > 0) {
+    fetch_all_from_fifo(active_uart[1]);
-        ringbuf_put(&active_uarts[1]->ringbuf, (uint8_t)UART1->IO_b.DATA);
-    }
     // We couldn't read all pending data (overrun) so clear the FIFO so that the interrupt
     // can finish.
     if (UART1->STAT_b.DATA_READY) {
@@ -79,6 +119,33 @@ void UART1_IRQHandler(void) {
     }
 }
 
+void pl011_IRQHandler(uint8_t index) {
+    fetch_all_from_fifo(active_uart[index]);
+    // Clear the interrupt in case we weren't able to clear it by emptying the
+    // FIFO. (This won't clear the FIFO.)
+    ARM_UART_PL011_Type *pl011 = uart[index];
+    pl011->ICR = UART0_ICR_RXIC_Msk;
+}
+
+void UART0_IRQHandler(void) {
+    pl011_IRQHandler(0);
+}
+
+#if BCM_VERSION == 2711
+void UART2_IRQHandler(void) {
+    pl011_IRQHandler(2);
+}
+void UART3_IRQHandler(void) {
+    pl011_IRQHandler(3);
+}
+void UART4_IRQHandler(void) {
+    pl011_IRQHandler(4);
+}
+void UART5_IRQHandler(void) {
+    pl011_IRQHandler(5);
+}
+#endif
+
 void common_hal_busio_uart_never_reset(busio_uart_obj_t *self) {
     uart_status[self->uart_id] = STATUS_NEVER_RESET;
 }
@@ -103,14 +170,43 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
         mp_raise_NotImplementedError(translate("RS485 Not yet supported on this device"));
     }
 
-    if (tx == &pin_GPIO14) {
+    size_t instance_index = NUM_UART;
-        if (rx == &pin_GPIO15) {
+    BP_Function_Enum tx_alt = 0;
-            self->uart_id = 1;
+    BP_Function_Enum rx_alt = 0;
+    BP_Function_Enum rts_alt = 0;
+    BP_Function_Enum cts_alt = 0;
+    for (size_t i = 0; i < NUM_UART; i++) {
+        if (uart_status[i] != STATUS_FREE) {
+            continue;
         }
+        if (tx != NULL) {
+            if (!pin_find_alt(tx, PIN_FUNCTION_UART, i, UART_FUNCTION_TXD, &tx_alt)) {
+                continue;
+            }
+            if (rts != NULL && !pin_find_alt(rts, PIN_FUNCTION_UART, i, UART_FUNCTION_RTS, &rts_alt)) {
+                continue;
+            }
+        }
+        if (rx != NULL) {
+            if (!pin_find_alt(rx, PIN_FUNCTION_UART, i, UART_FUNCTION_RXD, &rx_alt)) {
+                continue;
+            }
+            if (cts != NULL && !pin_find_alt(cts, PIN_FUNCTION_UART, i, UART_FUNCTION_CTS, &cts_alt)) {
+                continue;
+            }
+        }
+        instance_index = i;
+        break;
+    }
+    if (instance_index == NUM_UART) {
+        mp_raise_ValueError(translate("Invalid pins"));
     }
 
     self->rx_pin = rx;
     self->tx_pin = tx;
+    self->rts_pin = rts;
+    self->cts_pin = cts;
+    self->sigint_enabled = sigint_enabled;
 
     if (rx != NULL) {
         if (receiver_buffer != NULL) {
@@ -129,8 +225,11 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
         }
     }
 
+    active_uart[self->uart_id] = self;
+
+    ARM_UART_PL011_Type *pl011 = uart[self->uart_id];
+
     if (self->uart_id == 1) {
-        active_uarts[1] = self;
         AUX->ENABLES_b.UART_1 = true;
 
         UART1->IER = 0;
@@ -145,22 +244,80 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
 
         // Clear interrupts
         UART1->IIR = 0xff;
-        uint32_t source_clock = vcmailbox_get_clock_rate_measured(VCMAILBOX_CLOCK_CORE);
+        common_hal_busio_uart_set_baudrate(self, baudrate);
-        UART1->BAUD = ((source_clock / (baudrate * 8)) - 1);
         if (tx != NULL) {
             UART1->CNTL |= UART1_CNTL_TX_ENABLE_Msk;
-            gpio_set_pull(14, BP_PULL_NONE);
-            gpio_set_function(14, GPIO_GPFSEL1_FSEL14_TXD1);
         }
         if (rx != NULL) {
             UART1->CNTL |= UART1_CNTL_RX_ENABLE_Msk;
-            gpio_set_pull(15, BP_PULL_NONE);
-            gpio_set_function(15, GPIO_GPFSEL1_FSEL15_RXD1);
         }
+    } else {
+        // Ensure the UART is disabled as we configure it.
+        pl011->CR_b.UARTEN = false;
+        pl011->IMSC = 0;
+        pl011->ICR = 0x3ff;
+
+        common_hal_busio_uart_set_baudrate(self, baudrate);
+
+        uint32_t line_control = UART0_LCR_H_FEN_Msk;
+        line_control |= (bits - 5) << UART0_LCR_H_WLEN_Pos;
+        if (stop == 2) {
+            line_control |= UART0_LCR_H_STP2_Msk;
+        }
+        if (parity != BUSIO_UART_PARITY_NONE) {
+            line_control |= UART0_LCR_H_PEN_Msk;
+        }
+        if (parity == BUSIO_UART_PARITY_EVEN) {
+            line_control |= UART0_LCR_H_EPS_Msk;
+        }
+        pl011->LCR_H = line_control;
+
+        uint32_t control = UART0_CR_UARTEN_Msk;
+        if (tx != NULL) {
+            control |= UART0_CR_TXE_Msk;
+        }
+        if (rx != NULL) {
+            control |= UART0_CR_RXE_Msk;
+        }
+        if (cts != NULL) {
+            control |= UART0_CR_CTSEN_Msk;
+        }
+        if (rts != NULL) {
+            control |= UART0_CR_RTSEN_Msk;
+        }
+        pl011->CR = control;
+    }
+
+    // Setup the pins after waiting for UART stuff
+    COMPLETE_MEMORY_READS;
+    if (tx != NULL) {
+        gpio_set_pull(tx->number, BP_PULL_NONE);
+        gpio_set_function(tx->number, tx_alt);
+    }
+    if (rx != NULL) {
+        gpio_set_pull(rx->number, BP_PULL_NONE);
+        gpio_set_function(rx->number, rx_alt);
+    }
+    if (rts != NULL) {
+        gpio_set_pull(rts->number, BP_PULL_NONE);
+        gpio_set_function(rts->number, rts_alt);
+    }
+    if (cts != NULL) {
+        gpio_set_pull(cts->number, BP_PULL_NONE);
+        gpio_set_function(cts->number, cts_alt);
+    }
+
+    // Turn on interrupts
+    COMPLETE_MEMORY_READS;
+    if (self->uart_id == 1) {
         UART1->IER_b.DATA_READY = true;
         // Never disable this in case the SPIs are used. They can each be
         // disabled at the peripheral itself.
         BP_EnableIRQ(AUX_IRQn);
+    } else {
+        pl011->IMSC_b.RXIM = true;
+        // Never disable this in case the other PL011 UARTs are used.
+        BP_EnableIRQ(UART_IRQn);
     }
 }
 
@@ -176,8 +333,11 @@ void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {
         UART1->IER_b.DATA_READY = false;
         UART1->CNTL = 0;
         AUX->ENABLES_b.UART_1 = false;
-        active_uarts[1] = NULL;
+    } else {
+        ARM_UART_PL011_Type *pl011 = uart[self->uart_id];
+        pl011->CR = 0;
     }
+    active_uart[self->uart_id] = NULL;
     ringbuf_free(&self->ringbuf);
     uart_status[self->uart_id] = STATUS_FREE;
     common_hal_reset_pin(self->tx_pin);
@@ -196,20 +356,46 @@ size_t common_hal_busio_uart_write(busio_uart_obj_t *self, const uint8_t *data,
         mp_raise_ValueError(translate("No TX pin"));
     }
 
-    if (self->uart_id == 1) {
+    COMPLETE_MEMORY_READS;
-        COMPLETE_MEMORY_READS;
+    ARM_UART_PL011_Type *pl011 = uart[self->uart_id];
-        for (size_t i = 0; i < len; i++) {
+    for (size_t i = 0; i < len; i++) {
+        if (self->uart_id == 1) {
             // Wait for the FIFO to have space.
             while (!UART1->STAT_b.TX_READY) {
                 RUN_BACKGROUND_TASKS;
             }
             UART1->IO = data[i];
+        } else {
+            while (pl011->FR_b.TXFF) {
+                RUN_BACKGROUND_TASKS;
+            }
+            pl011->DR_b.DATA = data[i];
         }
-        COMPLETE_MEMORY_READS;
-        return len;
     }
+    // Wait for the data to be shifted out
+    if (self->uart_id == 1) {
+        while (!UART1->STAT_b.TX_DONE) {
+            RUN_BACKGROUND_TASKS;
+        }
+    } else {
+        while (pl011->FR_b.BUSY) {
+            RUN_BACKGROUND_TASKS;
+        }
+    }
+    COMPLETE_MEMORY_READS;
+    return len;
+}
 
-    return 0;
+STATIC void disable_interrupt(busio_uart_obj_t *self) {
+    if (self->uart_id == 1) {
+        UART1->IER_b.DATA_READY = false;
+    }
+}
+
+STATIC void enable_interrupt(busio_uart_obj_t *self) {
+    if (self->uart_id == 1) {
+        UART1->IER_b.DATA_READY = true;
+    }
 }
 
 // Read characters.
@@ -225,9 +411,7 @@ size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t
     COMPLETE_MEMORY_READS;
 
     // Prevent conflict with uart irq.
-    if (self->uart_id == 1) {
+    disable_interrupt(self);
-        UART1->IER_b.DATA_READY = false;
-    }
 
     // Copy as much received data as available, up to len bytes.
     size_t total_read = ringbuf_get_n(&self->ringbuf, data, len);
@@ -238,14 +422,11 @@ size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t
         uint64_t start_ticks = supervisor_ticks_ms64();
         // Busy-wait until timeout or until we've read enough chars.
         while (len > 0 && (supervisor_ticks_ms64() - start_ticks < self->timeout_ms)) {
-            if (UART1->STAT_b.DATA_READY) {
+            fetch_all_from_fifo(self);
-                // Read and advance.
+            size_t additional_read = ringbuf_get_n(&self->ringbuf, data + total_read, len);
-                data[total_read] = UART1->IO_b.DATA;
+            len -= additional_read;
-
+            total_read += additional_read;
-                // Adjust the counters.
+            if (additional_read > 0) {
-                len--;
-                total_read++;
-
                 // Reset the timeout on every character read.
                 start_ticks = supervisor_ticks_ms64();
             }
@@ -260,14 +441,10 @@ size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t
     // Now that we've emptied the ringbuf some, fill it up with anything in the
     // FIFO. This ensures that we'll empty the FIFO as much as possible and
     // reset the interrupt when we catch up.
-    while (UART1->STAT_b.DATA_READY && ringbuf_num_empty(&self->ringbuf) > 0) {
+    fetch_all_from_fifo(self);
-        ringbuf_put(&self->ringbuf, (uint8_t)UART1->IO_b.DATA);
-    }
 
     // Re-enable irq.
-    if (self->uart_id == 1) {
+    enable_interrupt(self);
-        UART1->IER_b.DATA_READY = true;
-    }
 
     COMPLETE_MEMORY_READS;
     if (total_read == 0) {
@@ -283,6 +460,31 @@ uint32_t common_hal_busio_uart_get_baudrate(busio_uart_obj_t *self) {
 }
 
 void common_hal_busio_uart_set_baudrate(busio_uart_obj_t *self, uint32_t baudrate) {
+    if (self->uart_id == 1) {
+        uint32_t source_clock = vcmailbox_get_clock_rate_measured(VCMAILBOX_CLOCK_CORE);
+        UART1->BAUD = ((source_clock / (baudrate * 8)) - 1);
+    } else {
+        ARM_UART_PL011_Type *pl011 = uart[self->uart_id];
+        bool reenable = false;
+        if (pl011->CR_b.UARTEN) {
+            pl011->CR_b.UARTEN = false;
+            reenable = true;
+        }
+        uint32_t source_clock = vcmailbox_get_clock_rate_measured(VCMAILBOX_CLOCK_UART);
+        uint32_t divisor = 16 * baudrate;
+        pl011->IBRD = source_clock / divisor;
+        // The fractional divisor is 64ths.
+        uint32_t remainder = source_clock % divisor;
+        uint32_t per_tick = (divisor / 64) + 1;
+        uint32_t adjust = 0;
+        if (remainder % per_tick > 0) {
+            adjust = 1;
+        }
+        pl011->FBRD = remainder / per_tick + adjust;
+        if (reenable) {
+            pl011->CR_b.UARTEN = true;
+        }
+    }
     self->baudrate = baudrate;
 }
 
@@ -295,6 +497,7 @@ void common_hal_busio_uart_set_timeout(busio_uart_obj_t *self, mp_float_t timeou
 }
 
 uint32_t common_hal_busio_uart_rx_characters_available(busio_uart_obj_t *self) {
+    fetch_all_from_fifo(self);
     return ringbuf_num_filled(&self->ringbuf);
 }
 
@@ -309,5 +512,5 @@ bool common_hal_busio_uart_ready_to_tx(busio_uart_obj_t *self) {
     if (self->uart_id == 1) {
         return UART1->STAT_b.TX_READY;
     }
-    return false;
+    return !uart[self->uart_id]->FR_b.TXFF;
 }

ports/broadcom/common-hal/busio/UART.h

@@ -39,6 +39,7 @@ typedef struct {
     uint8_t uart_id;
     uint32_t baudrate;
     uint32_t timeout_ms;
+    bool sigint_enabled;
     ringbuf_t ringbuf;
 } busio_uart_obj_t;
 

ports/broadcom/firmware

@@ -1 +1 @@
-Subproject commit 6a5207946edcd45813d1dd1572ca8bd8101b68b6
+Subproject commit bf96d0eda5952595d717fedb797aeb168483e9fa

ports/broadcom/peripherals

@@ -1 +1 @@
-Subproject commit 2e7b56bbe941311e54fba66f0b32336bfea4388d
+Subproject commit a0666ce987ae96a58e587a04b9f89c7c5707dd13