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https://github.com/ARM-software/arm-trusted-firmware.git
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9400b40ea4
The PL011 TRM (ARM DDI 0183G) specifies that the UART must be disabled before any of the control registers are programmed. The PL011 driver included in TF does not disable the UART, so the initialization in BL2 and BL31 is violating this requirement (and potentially in BL1 if the UART is enabled after reset). This patch modifies the initialization function in the PL011 console driver to disable the UART before programming the control registers. Register clobber list and documentation updated. Fixes ARM-software/tf-issues#300 Change-Id: I839b2d681d48b03f821ac53663a6a78e8b30a1a1
113 lines
4 KiB
ArmAsm
113 lines
4 KiB
ArmAsm
/*
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* Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of ARM nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <asm_macros.S>
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.globl console_init
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.globl console_uninit
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.globl console_putc
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.globl console_getc
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/*
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* The console base is in the data section and not in .bss
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* even though it is zero-init. In particular, this allows
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* the console functions to start using this variable before
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* the runtime memory is initialized for images which do not
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* need to copy the .data section from ROM to RAM.
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*/
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.section .data.console_base ; .align 3
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console_base: .quad 0x0
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/* -----------------------------------------------
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* int console_init(uintptr_t base_addr,
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* unsigned int uart_clk, unsigned int baud_rate)
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* Function to initialize the console without a
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* C Runtime to print debug information. It saves
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* the console base to the data section.
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* In: x0 - console base address
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* w1 - Uart clock in Hz
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* w2 - Baud rate
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* out: return 1 on success else 0 on error
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* Clobber list : x1 - x4
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* -----------------------------------------------
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*/
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func console_init
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/* Check the input base address */
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cbz x0, init_fail
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adrp x3, console_base
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str x0, [x3, :lo12:console_base]
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b console_core_init
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init_fail:
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ret
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endfunc console_init
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/* -----------------------------------------------
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* void console_uninit(void)
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* Function to finish the use of console driver.
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* It sets the console_base as NULL so that any
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* further invocation of `console_putc` or
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* `console_getc` APIs would return error.
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* -----------------------------------------------
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*/
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func console_uninit
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mov x0, #0
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adrp x3, console_base
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str x0, [x3, :lo12:console_base]
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ret
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endfunc console_uninit
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/* ---------------------------------------------
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* int console_putc(int c)
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* Function to output a character over the
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* console. It returns the character printed on
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* success or -1 on error.
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* In : x0 - character to be printed
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* Out : return -1 on error else return character.
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* Clobber list : x1, x2
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* ---------------------------------------------
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*/
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func console_putc
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adrp x2, console_base
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ldr x1, [x2, :lo12:console_base]
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b console_core_putc
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endfunc console_putc
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/* ---------------------------------------------
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* int console_getc(void)
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* Function to get a character from the console.
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* It returns the character grabbed on success
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* or -1 on error.
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* Clobber list : x0, x1
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* ---------------------------------------------
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*/
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func console_getc
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adrp x1, console_base
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ldr x0, [x1, :lo12:console_base]
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b console_core_getc
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endfunc console_getc
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