[PATCH v3 2/2] bsp/raspberrypi: Mini UART driver
G. S. Niteesh
gsnb.gn at gmail.com
Sun Feb 16 15:58:42 UTC 2020
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
> >>
> > _______________________________________________
> > devel mailing list
> > devel at rtems.org
> > http://lists.rtems.org/mailman/listinfo/devel
>
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