[PATCH v3 2/2] bsp/raspberrypi: Mini UART driver
G. S. Niteesh
gsnb.gn at gmail.com
Sun Feb 16 07:35:14 UTC 2020
Hii,
This is a reminder message since this patch has been unnoticed for a while.
I have tested it on Raspberry Pi 3 and it works fine. There is also another
patch
https://lists.rtems.org/pipermail/devel/2020-February/057194.html, please
do have a look at these.
Thank you.
Niteesh
On Mon, Feb 10, 2020 at 12:52 AM G S Niteesh <gsnb.gn at gmail.com> wrote:
> 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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