[PATCH v3 2/2] bsp/raspberrypi: Mini UART driver
Alan Cudmore
alan.cudmore at gmail.com
Sun Feb 16 16:28:42 UTC 2020
I tried running my raspberrypi BSP image that worked on the Pi Zero
and W, but it did not work on the Pi 3.
I built the raspberrypi2 BSP, used objcopy to copy the binary to my sd
card as kernel7.img, and it works on my Pi 3 and Pi3 A+ ( without
ethernet) . Note that my config.txt file does not specify the kernel
image, so the firmware defaults to kernel.img for the single core
models and kernel7.img for the 2 and 3.
I probably wont get a chance to try u-boot until later today or tomorrow.
But these patches are great for enabling the Pi Zero W and Pi 3 models!
Thanks,
Alan
On Sun, Feb 16, 2020 at 10:58 AM G. S. Niteesh <gsnb.gn at gmail.com> wrote:
>
> On Sun, Feb 16, 2020 at 8:37 PM Alan Cudmore <alan.cudmore at gmail.com> wrote:
>>
>> 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
>
> Hi Alan,
> First of all, thank you for taking this initiative.
> I have tried using the default bootloader in Pi3 to load RTEMS but it doesn't work,
> Can you try it?
> The currently use U-Boot in 32bit mode as the bootloader.
> You can use the below instructions to build U-Boot in 32bit mode
>
> git clone https://github.com/u-boot/u-boot.git u-boot
> cd u-boot
> git revert 995eab8b5b580b67394312b1621c60a71042cd18
> make CROSS_COMPILE=arm-linux-gnueabi- rpi_3_32b_defconfig
> make CROSS_COMPILE=arm-linux-gnueabi-
>
> This one uses an old version of U-Boot and I don't know if there is
> a new way to build in 32bit mode.
>
> To build the U-Boot image of RTEMS you can use the below instructions
>
> arm-rtems5-objcopy -Obinary hello.exe kernel.img
> mkimage -A arm -O linux -T kernel -a 0x200000 -e 0x200080 -d kernel.img -C none rtems.img
>
> To load and run in U-Boot
>
> fatload mmc 0 0x200000 rtems.img
> fatload mmc 0 0x1000 bcm2710-rpi-3-b.dtb
> bootm 0x200000 - 0x1000
>
> And to make your U-Boot build process simpler I have uploaded my u-boot.bin
> to my github, please use it :)
> https://github.com/gs-niteesh/rpi3_RTEMS
>
> And sorry for the delay, I tested all these instructions again before sending them.
>
> Thanks
> Niteesh.
>
> 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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>> > devel at rtems.org
>> > http://lists.rtems.org/mailman/listinfo/devel
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