diff options
author | Lokesh Vutla <lokeshvutla@ti.com> | 2018-04-26 15:51:30 +0300 |
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committer | Tom Rini <trini@konsulko.com> | 2018-05-07 22:53:29 +0300 |
commit | f2ef204312480bfba7700f47c8ce9fb975c26557 (patch) | |
tree | 3fd338e772be2cbec3c1a6b4a847d7d6ae673eae /arch/arm/cpu/armv7/mpu_v7r.c | |
parent | 4bbd6b1d946ab6165bff8aeae6f252faa07ce85a (diff) | |
download | u-boot-f2ef204312480bfba7700f47c8ce9fb975c26557.tar.xz |
arm: v7R: Add support for MPU
The Memory Protection Unit(MPU) allows to partition memory into regions
and set individual protection attributes for each region. In absence
of MPU a default map[1] will take effect. Add support for configuring
MPU on Cortex-R, by reusing the existing support for Cortex-M processor.
[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0460d/I1002400.html
Tested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Diffstat (limited to 'arch/arm/cpu/armv7/mpu_v7r.c')
-rw-r--r-- | arch/arm/cpu/armv7/mpu_v7r.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/mpu_v7r.c b/arch/arm/cpu/armv7/mpu_v7r.c new file mode 100644 index 0000000000..567d913414 --- /dev/null +++ b/arch/arm/cpu/armv7/mpu_v7r.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Cortex-R Memory Protection Unit specific code + * + * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/ + * Lokesh Vutla <lokeshvutla@ti.com> + */ + +#include <common.h> +#include <command.h> +#include <asm/armv7.h> +#include <asm/system.h> +#include <asm/barriers.h> +#include <linux/compiler.h> + +#include <asm/armv7_mpu.h> + +/* MPU Type register definitions */ +#define MPUIR_S_SHIFT 0 +#define MPUIR_S_MASK BIT(MPUIR_S_SHIFT) +#define MPUIR_DREGION_SHIFT 8 +#define MPUIR_DREGION_MASK (0xff << 8) + +/** + * Note: + * The Memory Protection Unit(MPU) allows to partition memory into regions + * and set individual protection attributes for each region. In absence + * of MPU a default map[1] will take effect. make sure to run this code + * from a region which has execution permissions by default. + * [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0460d/I1002400.html + */ + +void disable_mpu(void) +{ + u32 reg; + + reg = get_cr(); + reg &= ~CR_M; + dsb(); + set_cr(reg); + isb(); +} + +void enable_mpu(void) +{ + u32 reg; + + reg = get_cr(); + reg |= CR_M; + dsb(); + set_cr(reg); + isb(); +} + +int mpu_enabled(void) +{ + return get_cr() & CR_M; +} + +void mpu_config(struct mpu_region_config *rgn) +{ + u32 attr, val; + + attr = get_attr_encoding(rgn->mr_attr); + + /* MPU Region Number Register */ + asm volatile ("mcr p15, 0, %0, c6, c2, 0" : : "r" (rgn->region_no)); + + /* MPU Region Base Address Register */ + asm volatile ("mcr p15, 0, %0, c6, c1, 0" : : "r" (rgn->start_addr)); + + /* MPU Region Size and Enable Register */ + if (rgn->reg_size) + val = (rgn->reg_size << REGION_SIZE_SHIFT) | ENABLE_REGION; + else + val = DISABLE_REGION; + asm volatile ("mcr p15, 0, %0, c6, c1, 2" : : "r" (val)); + + /* MPU Region Access Control Register */ + val = rgn->xn << XN_SHIFT | rgn->ap << AP_SHIFT | attr; + asm volatile ("mcr p15, 0, %0, c6, c1, 4" : : "r" (val)); +} + +void setup_mpu_regions(struct mpu_region_config *rgns, u32 num_rgns) +{ + u32 num, i; + + asm volatile ("mrc p15, 0, %0, c0, c0, 4" : "=r" (num)); + num = (num & MPUIR_DREGION_MASK) >> MPUIR_DREGION_SHIFT; + /* Regions to be configured cannot be greater than available regions */ + if (num < num_rgns) + num_rgns = num; + /** + * Assuming dcache might not be enabled at this point, disabling + * and invalidating only icache. + */ + icache_disable(); + invalidate_icache_all(); + + disable_mpu(); + + for (i = 0; i < num_rgns; i++) + mpu_config(&rgns[i]); + + enable_mpu(); + + icache_enable(); +} |