u-boot/arch/arm/mach-mvebu/lowlevel.S
Pali Rohár 5818198e6a arm: mvebu: Fix moving internal registers
Commit 5bb2c550b1 ("arm: mvebu: Move internal registers in
arch_very_early_init() function") moved code from file cpu.c to lowlevel.c,
which moves Marvell internal registers from address INTREG_BASE_ADDR_REG to
SOC_REGS_PHY_BASE.

But the steps describing how to do it correctly were documented only in
older U-Boot versions and commit cefd764222 ("arm: mvebu: Fix internal
register config on A38x") probably unintentionally removed important
details about MMU from code comments around.

Commit 5bb2c550b1 ("arm: mvebu: Move internal registers in
arch_very_early_init() function") implemented code movement according to
(now incomplete) comments which resulted in semi-broken code.

The result is that I-cache is currently disabled for all Armada 38x boards
and maybe there are some other (unreported / undetected) issues.

Reimplement it correctly. First flush all caches, then disable MMU and L2
cache and then move Marvell internal registers. There is no need to
explicitly disable I-cache.

After this change lzmadec command with lzma image of 0x7000000 bytes is
doing decompression just 5 seconds. Before this change it was 30 seconds.

To make lowlevel.S code more readable, extend asm/pl310.h header file to be
compatible with assembler and use macros from this file.

Fixes: 5bb2c550b1 ("arm: mvebu: Move internal registers in arch_very_early_init() function")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
2022-09-13 09:04:22 +02:00

55 lines
1.5 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0+ */
#include <config.h>
#include <linux/linkage.h>
#include <asm/system.h>
#include <asm/pl310.h>
ENTRY(arch_very_early_init)
#ifdef CONFIG_ARMADA_38X
/*
* Only with disabled MMU its possible to switch the base
* register address on Armada 38x. Without this the SDRAM
* located at >= 0x4000.0000 is also not accessible, as its
* still locked to cache.
*
* So to fully release / unlock this area from cache, we need
* to first flush all caches, then disable the MMU and
* disable the L2 cache.
*/
/* Invalidate L1 I/D */
mov r0, #0 @ set up for MCR
mcr p15, 0, r0, c8, c7, 0 @ invalidate TLBs
mcr p15, 0, r0, c7, c5, 0 @ invalidate icache
mcr p15, 0, r0, c7, c5, 6 @ invalidate BP array
mcr p15, 0, r0, c7, c10, 4 @ DSB
mcr p15, 0, r0, c7, c5, 4 @ ISB
/* Disable MMU */
mrc p15, 0, r0, c1, c0, 0
bic r0, #CR_M
mcr p15, 0, r0, c1, c0, 0
/*
* Disable L2 cache
*
* NOTE: Internal registers are still at address INTREG_BASE_ADDR_REG
* but CONFIG_SYS_PL310_BASE is already calculated from base
* address SOC_REGS_PHY_BASE.
*/
ldr r1, =(CONFIG_SYS_PL310_BASE - SOC_REGS_PHY_BASE + INTREG_BASE_ADDR_REG)
ldr r0, [r1, #L2X0_CTRL_OFF]
bic r0, #L2X0_CTRL_EN
str r0, [r1, #L2X0_CTRL_OFF]
#endif
/* Move internal registers from INTREG_BASE_ADDR_REG to SOC_REGS_PHY_BASE */
ldr r0, =SOC_REGS_PHY_BASE
ldr r1, =INTREG_BASE_ADDR_REG
str r0, [r1]
add r0, r0, #0xC000
mcr p15, 4, r0, c15, c0
bx lr
ENDPROC(arch_very_early_init)