[PATCH v3 2/2] bsp/raspberrypi: Mini UART driver
G S Niteesh
gsnb.gn at gmail.com
Sun Feb 9 19:21:44 UTC 2020
This patch adds driver for Mini UART present in Raspberry Pi 3
and above, this UART is currently used as the primary UART in
these models.
The Mini UART is similar to ns16550, this driver is built
upon libchip/ns16550.
---
bsps/arm/raspberrypi/console/console-config.c | 118 ++++++++++++++++--
bsps/arm/raspberrypi/include/bsp/usart.h | 1 +
2 files changed, 110 insertions(+), 9 deletions(-)
diff --git a/bsps/arm/raspberrypi/console/console-config.c b/bsps/arm/raspberrypi/console/console-config.c
index 48c4c6a3ec..62196786dd 100644
--- a/bsps/arm/raspberrypi/console/console-config.c
+++ b/bsps/arm/raspberrypi/console/console-config.c
@@ -24,6 +24,7 @@
#include <libchip/serial.h>
#include <libfdt.h>
+#include <libchip/ns16550.h>
#include <bspopts.h>
#include <bsp/usart.h>
@@ -34,35 +35,103 @@
#include <bsp/console-termios.h>
#include <bsp/fdt.h>
#include <bsp/fatal.h>
+#include <bsp/gpio.h>
+#include <bsp/rpi-gpio.h>
-
-#define UART0 "/dev/ttyS0"
+/**
+ * UART0 - PL011
+ * UART1 - Mini UART
+ */
+#define PL011 "/dev/ttyAMA0"
+#define MINIUART "/dev/ttyS0"
#define FBCONS "/dev/fbcons"
arm_pl011_context pl011_context;
+ns16550_context mini_uart_context;
rpi_fb_context fb_context;
-static void output_char_serial(char c)
+static void output_char_pl011(char c)
{
arm_pl011_write_polled(&pl011_context.base, c);
}
+static void output_char_mini_uart(char c)
+{
+ ns16550_polled_putchar(&mini_uart_context.base, c);
+}
+
void output_char_fb(char c)
{
fbcons_write_polled(&fb_context.base, c);
}
+static uint8_t mini_uart_get_reg(uintptr_t port, uint8_t index)
+{
+ volatile uint32_t *val = (volatile uint32_t *)port + index;
+ return (uint8_t) *val;
+}
+
+static void mini_uart_set_reg(uintptr_t port, uint8_t index, uint8_t val)
+{
+ volatile uint32_t *reg = (volatile uint32_t *)port + index;
+ *reg = val;
+}
+
static void init_ctx_arm_pl011(
const void *fdt,
int node
)
{
arm_pl011_context *ctx = &pl011_context;
- rtems_termios_device_context_initialize(&ctx->base, "UART");
+ rtems_termios_device_context_initialize(&ctx->base, "PL011UART");
ctx->regs = raspberrypi_get_reg_of_node(fdt, node);
}
+static uint32_t calculate_baud_divisor(
+ ns16550_context *ctx,
+ uint32_t baud
+)
+{
+ uint32_t baudDivisor = (ctx->clock / (8 * baud)) - 1;
+ return baudDivisor;
+}
+
+static void init_ctx_mini_uart(
+ const void *fdt,
+ int node
+)
+{
+ const char *status;
+ int len;
+ ns16550_context *ctx;
+
+ memset(&mini_uart_context, 0, sizeof(mini_uart_context));
+ ctx = &mini_uart_context;
+
+ rtems_termios_device_context_initialize(&ctx->base, "MiniUART");
+
+ status = fdt_getprop(fdt, node, "status", &len);
+ if ( status == NULL || strcmp(status, "disabled" ) == 0){
+ return ;
+ }
+
+ ctx->port = (uintptr_t) raspberrypi_get_reg_of_node(fdt, node);
+ ctx->initial_baud = MINI_UART_DEFAULT_BAUD;
+ ctx->clock = BCM2835_CLOCK_FREQ;
+ ctx->calculate_baud_divisor = calculate_baud_divisor;
+ ctx->get_reg = mini_uart_get_reg;
+ ctx->set_reg = mini_uart_set_reg;
+
+ rtems_gpio_bsp_select_specific_io(0, 14, RPI_ALT_FUNC_5, NULL);
+ rtems_gpio_bsp_select_specific_io(0, 15, RPI_ALT_FUNC_5, NULL);
+ rtems_gpio_bsp_set_resistor_mode(0, 14, NO_PULL_RESISTOR);
+ rtems_gpio_bsp_set_resistor_mode(0, 15, NO_PULL_RESISTOR);
+
+ BCM2835_REG(AUX_ENABLES) |= 0x1;
+ ns16550_probe(&ctx->base);
+}
+
static void register_fb( void )
{
if (fbcons_probe(&fb_context.base) == true) {
@@ -87,16 +156,28 @@ static void console_select( void )
link(FBCONS, CONSOLE_DEVICE_NAME);
return ;
}
+ } else if ( strncmp( opt, MINIUART, sizeof(MINIUART) - 1 ) == 0) {
+ BSP_output_char = output_char_mini_uart;
+ link(MINIUART, CONSOLE_DEVICE_NAME);
+ } else if ( strncmp( opt, PL011, sizeof(PL011) - 1 ) == 0) {
+ BSP_output_char = output_char_pl011;
+ link(PL011, CONSOLE_DEVICE_NAME);
}
+ }else {
+ /**
+ * If no command line option was given, default to PL011.
+ */
+ BSP_output_char = output_char_pl011;
+ link(PL011, CONSOLE_DEVICE_NAME);
}
- BSP_output_char = output_char_serial;
- link(UART0, CONSOLE_DEVICE_NAME);
}
static void uart_probe(void)
{
static bool initialized = false;
const void *fdt;
+ const char *console;
+ int len;
int node;
if ( initialized ) {
@@ -104,17 +185,29 @@ static void uart_probe(void)
}
fdt = bsp_fdt_get();
- node = fdt_node_offset_by_compatible(fdt, -1, "brcm,bcm2835-pl011");
+ node = fdt_node_offset_by_compatible(fdt, -1, "brcm,bcm2835-pl011");
init_ctx_arm_pl011(fdt, node);
+ node = fdt_node_offset_by_compatible(fdt, -1, "brcm,bcm2835-aux-uart");
+ init_ctx_mini_uart(fdt, node);
+
+ node = fdt_path_offset(fdt, "/aliases");
+ console = fdt_getprop(fdt, node, "serial0", &len);
+
+ if ( strcmp(console, "/soc/serial at 7e215040" ) == 0) {
+ BSP_output_char = output_char_mini_uart;
+ }else {
+ BSP_output_char = output_char_pl011;
+ }
+
initialized = true;
}
static void output_char(char c)
{
uart_probe();
- output_char_serial(c);
+ (*BSP_output_char)(c);
}
rtems_status_code console_initialize(
@@ -127,12 +220,19 @@ rtems_status_code console_initialize(
uart_probe();
rtems_termios_device_install(
- UART0,
+ PL011,
&arm_pl011_fns,
NULL,
&pl011_context.base
);
+ rtems_termios_device_install(
+ MINIUART,
+ &ns16550_handler_polled,
+ NULL,
+ &mini_uart_context.base
+ );
+
register_fb();
console_select();
diff --git a/bsps/arm/raspberrypi/include/bsp/usart.h b/bsps/arm/raspberrypi/include/bsp/usart.h
index abbf53626c..6af1844b3c 100644
--- a/bsps/arm/raspberrypi/include/bsp/usart.h
+++ b/bsps/arm/raspberrypi/include/bsp/usart.h
@@ -33,6 +33,7 @@ extern "C" {
#endif /* __cplusplus */
#define PL011_DEFAULT_BAUD 115000
+#define MINI_UART_DEFAULT_BAUD 115200
#define BCM2835_PL011_BASE (RPI_PERIPHERAL_BASE + 0x201000)
#ifdef __cplusplus
--
2.17.1
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