[PATCH v3 2/2] bsp/raspberrypi: Mini UART driver
Alan Cudmore
alan.cudmore at gmail.com
Sun Feb 16 15:07:45 UTC 2020
Hi Niteesh,
I can try this patch on my Pi 3. Which BSP should I use? Is there any
special setup or BSP configuration needed?
Thanks,
Alan
On Sun, Feb 16, 2020 at 2:35 AM G. S. Niteesh <gsnb.gn at gmail.com> wrote:
>
> 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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