forked from Minki/linux
b2aa7f7741
STM32F429 allows to remap FMC SDRAM Bank 1 from 0xc0000000 to 0x0, by writing 0x4 to SYSCFG_MEMRMP register. As mentionned in the reference manual (see chapter 9.3.1), the performance gain is really interresting: "In remap mode at address 0x0000 0000, the CPU can access the external memory via ICode bus instead of System bus which boosts up the performance." These are the dhrystone results with and without the remap enabled: Default (SDRAM in 0xc0000000): --------------------------------- Microseconds for one run through Dhrystone: 31.8 Dhrystones per Second: 31416.9 Remap (SDRAM in 0x0000000): ----------------------------- Microseconds for one run through Dhrystone: 20.6 Dhrystones per Second: 48520.1 This patch first change the SDRAM start address to 0x0 for STM32429i-EVAL board, and also set the dma-range property as the other masters than the M4 CPU still see SDRAM in 0xc0000000. Note that the Discovery board cannot benefit from this feature, since the SDRAM is connected to Bank 2. Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
95 lines
2.9 KiB
Plaintext
95 lines
2.9 KiB
Plaintext
/*
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* Copyright 2015 - Maxime Coquelin <mcoquelin.stm32@gmail.com>
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*
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* This file is dual-licensed: you can use it either under the terms
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* of the GPL or the X11 license, at your option. Note that this dual
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* licensing only applies to this file, and not this project as a
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* whole.
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*
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* a) This file is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this file; if not, write to the Free
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* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*
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* Or, alternatively,
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*
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* b) Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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/dts-v1/;
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#include "stm32f429.dtsi"
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/ {
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model = "STMicroelectronics STM32429i-EVAL board";
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compatible = "st,stm32429i-eval", "st,stm32f429";
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chosen {
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bootargs = "root=/dev/ram rdinit=/linuxrc";
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stdout-path = "serial0:115200n8";
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};
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memory {
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reg = <0x00000000 0x2000000>;
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};
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aliases {
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serial0 = &usart1;
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};
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leds {
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compatible = "gpio-leds";
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green {
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gpios = <&gpiog 6 1>;
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linux,default-trigger = "heartbeat";
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};
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orange {
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gpios = <&gpiog 7 1>;
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};
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red {
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gpios = <&gpiog 10 1>;
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};
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blue {
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gpios = <&gpiog 12 1>;
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};
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};
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};
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&clk_hse {
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clock-frequency = <25000000>;
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};
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&usart1 {
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pinctrl-0 = <&usart1_pins_a>;
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pinctrl-names = "default";
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status = "okay";
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};
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