drivers: ti: uart: add a aarch32 variant

Rockchip re-uses the ti uart console driver and for aarch32 needs a
specific variant, so add it.
There are also aarch32 ti socs, so it may be useful for them as well
at some point.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Change-Id: I31ede7cc7b10347b3691cff051db2b985fd59e17

drivers/ti/uart/aarch32/16550_console.S

+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <assert_macros.S>
+#include <console_macros.S>
+#include <drivers/ti/uart/uart_16550.h>
+
+	/*
+	 * "core" functions are low-level implementations that don't require
+	 * writable memory and are thus safe to call in BL1 crash context.
+	 */
+	.globl console_16550_core_init
+	.globl console_16550_core_putc
+	.globl console_16550_core_getc
+	.globl console_16550_core_flush
+
+	.globl console_16550_putc
+	.globl console_16550_getc
+	.globl console_16550_flush
+
+	/* -----------------------------------------------
+	 * int console_16550_core_init(uintptr_t base_addr,
+	 * unsigned int uart_clk, unsigned int baud_rate)
+	 * Function to initialize the console without a
+	 * C Runtime to print debug information. This
+	 * function will be accessed by console_init and
+	 * crash reporting.
+	 * In: r0 - console base address
+	 *     r1 - Uart clock in Hz
+	 *     r2 - Baud rate
+	 * Out: return 1 on success, 0 on error
+	 * Clobber list : r1, r2, r3
+	 * -----------------------------------------------
+	 */
+func console_16550_core_init
+	/* Check the input base address */
+	cmp	r0, #0
+	beq	init_fail
+	/* Check baud rate and uart clock for sanity */
+	cmp	r1, #0
+	beq	init_fail
+	cmp	r2, #0
+	beq	init_fail
+
+	/* Program the baudrate */
+	/* Divisor =  Uart clock / (16 * baudrate) */
+	lsl	r2, r2, #4
+	udiv	r2, r1, r2
+	and	r1, r2, #0xff		/* w1 = DLL */
+	lsr	r2, r2, #8
+	and	r2, r2, #0xff		/* w2 = DLLM */
+	ldr	r3, [r0, #UARTLCR]
+	orr	r3, r3, #UARTLCR_DLAB
+	str	r3, [r0, #UARTLCR]	/* enable DLL, DLLM programming */
+	str	r1, [r0, #UARTDLL]	/* program DLL */
+	str	r2, [r0, #UARTDLLM]	/* program DLLM */
+	mov	r2, #~UARTLCR_DLAB
+	and	r3, r3, r2
+	str	r3, [r0, #UARTLCR]	/* disable DLL, DLLM programming */
+
+	/* 8n1 */
+	mov	r3, #3
+	str	r3, [r0, #UARTLCR]
+	/* no interrupt */
+	mov	r3, #0
+	str	r3, [r0, #UARTIER]
+#ifdef TI_16550_MDR_QUIRK
+	/* UART must be enabled on some platforms via the MDR register */
+	str	r3, [r0, #UARTMDR1]
+#endif /* TI_16550_MDR_QUIRK */
+	/* enable fifo, DMA */
+	mov	r3, #(UARTFCR_FIFOEN | UARTFCR_DMAEN)
+	str	r3, [r0, #UARTFCR]
+	/* DTR + RTS */
+	mov	r3, #3
+	str	r3, [r0, #UARTMCR]
+	mov	r0, #1
+	bx	lr
+init_fail:
+	mov	r0, #0
+	bx	lr
+endfunc console_16550_core_init
+
+	.globl console_16550_register
+
+	/* -------------------------------------------------------
+	 * int console_stm32_register(uintptr_t baseaddr,
+	 *     uint32_t clock, uint32_t baud,
+	 *     struct console_stm32 *console);
+	 * Function to initialize and register a new STM32
+	 * console. Storage passed in for the console struct
+	 * *must* be persistent (i.e. not from the stack).
+	 * In: r0 - UART register base address
+	 *     r1 - UART clock in Hz
+	 *     r2 - Baud rate
+	 *     r3 - pointer to empty console_stm32 struct
+	 * Out: return 1 on success, 0 on error
+	 * Clobber list : r0, r1, r2
+	 * -------------------------------------------------------
+	 */
+func console_16550_register
+	push	{r4, lr}
+	mov	r4, r3
+	cmp	r4, #0
+	beq	register_fail
+	str	r0, [r4, #CONSOLE_T_16550_BASE]
+
+	bl	console_16550_core_init
+	cmp	r0, #0
+	beq	register_fail
+
+	mov	r0, r4
+	pop	{r4, lr}
+	finish_console_register 16550 putc=1, getc=1, flush=1
+
+register_fail:
+	pop	{r4, pc}
+endfunc console_16550_register
+
+	/* --------------------------------------------------------
+	 * int console_16550_core_putc(int c, uintptr_t base_addr)
+	 * Function to output a character over the console. It
+	 * returns the character printed on success or -1 on error.
+	 * In : r0 - character to be printed
+	 *      r1 - console base address
+	 * Out : return -1 on error else return character.
+	 * Clobber list : r2
+	 * --------------------------------------------------------
+	 */
+func console_16550_core_putc
+#if ENABLE_ASSERTIONS
+	cmp	r1, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+
+	/* Prepend '\r' to '\n' */
+	cmp	r0, #0xA
+	bne	2f
+	/* Check if the transmit FIFO is full */
+1:	ldr	r2, [r1, #UARTLSR]
+	and	r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE)
+	cmp	r2, #(UARTLSR_TEMT | UARTLSR_THRE)
+	bne	1b
+	mov	r2, #0xD		/* '\r' */
+	str	r2, [r1, #UARTTX]
+
+	/* Check if the transmit FIFO is full */
+2:	ldr	r2, [r1, #UARTLSR]
+	and	r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE)
+	cmp	r2, #(UARTLSR_TEMT | UARTLSR_THRE)
+	bne	2b
+	str	r0, [r1, #UARTTX]
+	bx	lr
+endfunc console_16550_core_putc
+
+	/* --------------------------------------------------------
+	 * int console_16550_putc(int c, console_16550_t *console)
+	 * Function to output a character over the console. It
+	 * returns the character printed on success or -1 on error.
+	 * In : r0 - character to be printed
+	 *      r1 - pointer to console_t structure
+	 * Out : return -1 on error else return character.
+	 * Clobber list : r2
+	 * --------------------------------------------------------
+	 */
+func console_16550_putc
+#if ENABLE_ASSERTIONS
+	cmp	r1, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+	ldr	r1, [r1, #CONSOLE_T_16550_BASE]
+	b	console_16550_core_putc
+endfunc console_16550_putc
+
+	/* ---------------------------------------------
+	 * int console_16550_core_getc(uintptr_t base_addr)
+	 * Function to get a character from the console.
+	 * It returns the character grabbed on success
+	 * or -1 on if no character is available.
+	 * In :  r0 - console base address
+	 * Clobber list : r0, r1
+	 * ---------------------------------------------
+	 */
+func console_16550_core_getc
+#if ENABLE_ASSERTIONS
+	cmp	r0, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+
+	/* Check if the receive FIFO is empty */
+1:	ldr	r1, [r0, #UARTLSR]
+	tst	r1, #UARTLSR_RDR_BIT
+	beq	no_char
+	ldr	r1, [r0, #UARTRX]
+	mov	r0, r1
+	bx	lr
+no_char:
+	mov	r0, #ERROR_NO_PENDING_CHAR
+	bx	lr
+endfunc console_16550_core_getc
+
+	/* ---------------------------------------------
+	 * int console_16550_getc(console_16550_t *console)
+	 * Function to get a character from the console.
+	 * It returns the character grabbed on success
+	 * or -1 on if no character is available.
+	 * In :  r0 - pointer to console_t stucture
+	 * Out : r0 - character if available, else -1
+	 * Clobber list : r0, r1
+	 * ---------------------------------------------
+	 */
+func console_16550_getc
+#if ENABLE_ASSERTIONS
+	cmp	r0, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+	ldr	r0, [r0, #CONSOLE_T_16550_BASE]
+	b	console_16550_core_getc
+endfunc console_16550_getc
+
+	/* ---------------------------------------------
+	 * int console_16550_core_flush(uintptr_t base_addr)
+	 * Function to force a write of all buffered
+	 * data that hasn't been output.
+	 * In : r0 - console base address
+	 * Out : return -1 on error else return 0.
+	 * Clobber list : r0, r1
+	 * ---------------------------------------------
+	 */
+func console_16550_core_flush
+#if ENABLE_ASSERTIONS
+	cmp	r0, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+
+	/* Loop until the transmit FIFO is empty */
+1:	ldr	r1, [r0, #UARTLSR]
+	and	r1, r1, #(UARTLSR_TEMT | UARTLSR_THRE)
+	cmp	r1, #(UARTLSR_TEMT | UARTLSR_THRE)
+	bne	1b
+
+	mov	r0, #0
+	bx	lr
+endfunc console_16550_core_flush
+
+	/* ---------------------------------------------
+	 * int console_16550_flush(console_pl011_t *console)
+	 * Function to force a write of all buffered
+	 * data that hasn't been output.
+	 * In : r0 - pointer to console_t structure
+	 * Out : return -1 on error else return 0.
+	 * Clobber list : r0, r1
+	 * ---------------------------------------------
+	 */
+func console_16550_flush
+#if ENABLE_ASSERTIONS
+	cmp	r0, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+	ldr	r0, [r0, #CONSOLE_T_16550_BASE]
+	b	console_16550_core_flush
+endfunc console_16550_flush