embox

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/**
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 * @file
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 * @brief Raspberry Pi 16550-like Mini UART driver
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 * Mini UART is the default console device on Raspberry Pi models with
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 * Bluetooth and WiFi. But some registers are different. For example,
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 * we need enable manually the mini UART by writting into base_address
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 * + 0x04 Auxiliary Enable Register.
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 * There are Extra Control Register and Extra Status Register as well,
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 * in purpose to provide a more intelligent way to manage RX/TX. But
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 * up to now, the driver adopts a full 16550-like solution.
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 * There is a Baudrate Register as a shortcut to get and set Baudrate.
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 *
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 * @author  Weixuan XIAO
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 * @date    09.11.2020
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 */
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#include <hal/reg.h>
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#include <drivers/common/memory.h>
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#include <drivers/diag.h>
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#include <embox/unit.h>
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#include <framework/mod/options.h>
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#include <hal/mmu.h>
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#include <mem/vmem.h>
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#include <util/binalign.h>
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#include <drivers/serial/uart_dev.h>
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#include <drivers/serial/diag_serial.h>
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#include <kernel/printk.h>
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#define REG_WIDTH    OPTION_GET(NUMBER,reg_width)
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#define COM0_IRQ_NUM OPTION_GET(NUMBER, irq_num)
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#define AUX_ENABLE ((volatile unsigned int*)(OPTION_GET(NUMBER, base_addr) + 0x04))
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#define AUX_MU_IO_OFFSET 0x40
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#define COM_BASE (OPTION_GET(NUMBER, base_addr) + AUX_MU_IO_OFFSET)
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#define MINI_UART_IER_RX_IRQ 0x01
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#define UART_REG(x)													\
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        unsigned char x;											\
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        unsigned char postpad_##x[REG_WIDTH - 1];
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struct com {
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        UART_REG(io);          	/* Mini Uart I/O Data */
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        UART_REG(ier);          /* Mini Uart Interrupt Enable */
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        UART_REG(iir);          /* Mini Uart Interrupt Identify */
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        UART_REG(lcr);          /* Mini Uart Line Control */
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        UART_REG(mcr);          /* Mini Uart Modem Control */
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        UART_REG(lsr);          /* Mini Uart Line Status */
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        UART_REG(msr);          /* Mini Uart Modem Status */
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        UART_REG(scr);          /* Mini Uart Scratch */
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        UART_REG(cntl);         /* Mini Uart Extra Control */
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        UART_REG(stat);         /* Mini Uart Extra Status */
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        UART_REG(baud);         /* Mini Uart Baudrate */
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};
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#define COM3 ((volatile struct com *)COM_BASE)
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#define COM3_LSR (COM3->lsr)
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#define COM3_IER (COM3->ier)
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#define COM3_IO (COM3->io)
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#define COM3_CNTL (COM3->cntl)
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EMBOX_UNIT_INIT(rpi_mini_uart_init);
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static int rpi_mini_uart_setup(struct uart *dev, const struct uart_params *params) {
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	*AUX_ENABLE |= 0x01;	/* enable mini uart */
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	if (params->uart_param_flags & UART_PARAM_FLAGS_USE_IRQ) {
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		COM3_IER |= MINI_UART_IER_RX_IRQ;
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	}
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	COM3_CNTL = 0x03;		/* enable tx and rx */
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	return 0;
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}
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static int rpi_mini_uart_irq_en(struct uart *dev, const struct uart_params *params) {
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	COM3_IER |= MINI_UART_IER_RX_IRQ;
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	return 0;
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}
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static int rpi_mini_uart_irq_dis(struct uart *dev, const struct uart_params *params) {
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	COM3_IER &= ~MINI_UART_IER_RX_IRQ;
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	return 0;
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}
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static int rpi_mini_uart_putc(struct uart *dev, int ch) {
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	while ((COM3_LSR & 0x20) == 0);	/* wait until we can send */
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	COM3_IO = ch;
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	return 0;
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}
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static int rpi_mini_uart_getc(struct uart *dev) {
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	return COM3_IO;
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}
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static int rpi_mini_uart_has_symbol(struct uart *dev) {
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	return COM3_LSR & 0x01;
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}
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static const struct uart_ops rpi_mini_uart_ops = {
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		.uart_getc = rpi_mini_uart_getc,
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		.uart_putc = rpi_mini_uart_putc,
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		.uart_hasrx = rpi_mini_uart_has_symbol,
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		.uart_setup = rpi_mini_uart_setup,
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		.uart_irq_en = rpi_mini_uart_irq_en,
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		.uart_irq_dis = rpi_mini_uart_irq_dis,
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};
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static struct uart uart0 = {
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		.uart_ops = &rpi_mini_uart_ops,
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		.irq_num = COM0_IRQ_NUM,
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		.base_addr = COM_BASE,
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};
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static const struct uart_params uart_defparams = {
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		.baud_rate = OPTION_GET(NUMBER,baud_rate),
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		.uart_param_flags = UART_PARAM_FLAGS_8BIT_WORD | UART_PARAM_FLAGS_USE_IRQ,
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};
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static const struct uart_params uart_diag_params = {
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		.baud_rate = OPTION_GET(NUMBER,baud_rate),
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		.uart_param_flags = UART_PARAM_FLAGS_8BIT_WORD,
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};
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DIAG_SERIAL_DEF(&uart0, &uart_diag_params);
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static int rpi_mini_uart_init(void) {
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	return uart_register(&uart0, &uart_defparams);
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}
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PERIPH_MEMORY_DEFINE(rpi_mini_uart, COM_BASE, 0x1000);
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