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![Patrice Chotard](/assets/img/avatar_default.png)
On linux kernel side, on STM32F7 and STM32H7 SoCs, DMA requires uncachable regions. These regions are defined in DT. Since kernel linux v4.15, on ARMv7-M Cortex, kernel is able to configure MPU regions depending on DT settings. As kernel is able to configure MPU, this allows to remove MPU region settings in bootloader. On Cortex M processors, MPU allows to use a default memory map. (see B3.5.4 MPU Control Register, MPU_CTRL in https://developer.arm.com/products/architecture/m-profile/docs/ddi0403/latest/armv7-m-architecture-reference-manual) Use the default memory map as background region for all STM32 SoCs family with an additional MPU region corresponding to the SDRAM area. Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
43 lines
916 B
C
43 lines
916 B
C
/*
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* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
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* Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <asm/io.h>
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#include <asm/armv7m_mpu.h>
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int arch_cpu_init(void)
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{
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int i;
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struct mpu_region_config stm32_region_config[] = {
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/*
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* Make SDRAM area cacheable & executable.
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*/
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#if defined(CONFIG_STM32F4)
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{ 0x00000000, REGION_0, XN_DIS, PRIV_RW_USR_RW,
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O_I_WB_RD_WR_ALLOC, REGION_16MB },
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#endif
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#if defined(CONFIG_STM32F7)
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{ 0xC0000000, REGION_0, XN_DIS, PRIV_RW_USR_RW,
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O_I_WB_RD_WR_ALLOC, REGION_16MB },
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#endif
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#if defined(CONFIG_STM32H7)
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{ 0xD0000000, REGION_0, XN_DIS, PRIV_RW_USR_RW,
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O_I_WB_RD_WR_ALLOC, REGION_32MB },
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#endif
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};
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disable_mpu();
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for (i = 0; i < ARRAY_SIZE(stm32_region_config); i++)
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mpu_config(&stm32_region_config[i]);
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enable_mpu();
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return 0;
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}
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