linux/arch/arm/mach-tegra/reset-handler.S
Stephen Warren c34f30e588 ARM: tegra: add CPU errata WARs to Tegra reset handler
The CPU cores in Tegra contain some errata. Workarounds must be applied
for these every time a CPU boots. Implement those workarounds directly
in the Tegra-specific CPU reset vector.

Many of these workarounds duplicate code in the core ARM kernel.

However, the core ARM kernel cannot enable those workarounds when
building a multi-platform kernel, since they require writing to secure-
only registers, and a multi-platform kernel often does not run in secure
mode, and also cannot generically/architecturally detect whether it is
running in secure mode, and hence cannot either unconditionally or
conditionally apply these workarounds.

Instead, the workarounds must be applied in architecture-specific reset
code, which is able to have more direct knowledge of the secure/normal
state. On Tegra, we will be able to detect this using a non-architected
register in the future, although we currently assume the kernel runs only
in secure mode. Other SoCs may never run the kernel in secure mode, and
hence always rely on a secure monitor to enable the workarounds, and
hence never implement them in the kernel.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
2013-03-11 14:29:22 -06:00

273 lines
6.6 KiB
ArmAsm

/*
* Copyright (c) 2012, NVIDIA Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/cache.h>
#include <asm/asm-offsets.h>
#include <asm/hardware/cache-l2x0.h>
#include "flowctrl.h"
#include "iomap.h"
#include "reset.h"
#include "sleep.h"
#define APB_MISC_GP_HIDREV 0x804
#define PMC_SCRATCH41 0x140
#define RESET_DATA(x) ((TEGRA_RESET_##x)*4)
#ifdef CONFIG_PM_SLEEP
/*
* tegra_resume
*
* CPU boot vector when restarting the a CPU following
* an LP2 transition. Also branched to by LP0 and LP1 resume after
* re-enabling sdram.
*/
ENTRY(tegra_resume)
bl v7_invalidate_l1
/* Enable coresight */
mov32 r0, 0xC5ACCE55
mcr p14, 0, r0, c7, c12, 6
cpu_id r0
cmp r0, #0 @ CPU0?
bne cpu_resume @ no
#ifdef CONFIG_ARCH_TEGRA_3x_SOC
/* Are we on Tegra20? */
mov32 r6, TEGRA_APB_MISC_BASE
ldr r0, [r6, #APB_MISC_GP_HIDREV]
and r0, r0, #0xff00
cmp r0, #(0x20 << 8)
beq 1f @ Yes
/* Clear the flow controller flags for this CPU. */
mov32 r2, TEGRA_FLOW_CTRL_BASE + FLOW_CTRL_CPU0_CSR @ CPU0 CSR
ldr r1, [r2]
/* Clear event & intr flag */
orr r1, r1, \
#FLOW_CTRL_CSR_INTR_FLAG | FLOW_CTRL_CSR_EVENT_FLAG
movw r0, #0x0FFD @ enable, cluster_switch, immed, & bitmaps
bic r1, r1, r0
str r1, [r2]
1:
#endif
#ifdef CONFIG_HAVE_ARM_SCU
/* enable SCU */
mov32 r0, TEGRA_ARM_PERIF_BASE
ldr r1, [r0]
orr r1, r1, #1
str r1, [r0]
#endif
/* L2 cache resume & re-enable */
l2_cache_resume r0, r1, r2, l2x0_saved_regs_addr
b cpu_resume
ENDPROC(tegra_resume)
#endif
#ifdef CONFIG_CACHE_L2X0
.globl l2x0_saved_regs_addr
l2x0_saved_regs_addr:
.long 0
#endif
.align L1_CACHE_SHIFT
ENTRY(__tegra_cpu_reset_handler_start)
/*
* __tegra_cpu_reset_handler:
*
* Common handler for all CPU reset events.
*
* Register usage within the reset handler:
*
* Others: scratch
* R6 = SoC ID << 8
* R7 = CPU present (to the OS) mask
* R8 = CPU in LP1 state mask
* R9 = CPU in LP2 state mask
* R10 = CPU number
* R11 = CPU mask
* R12 = pointer to reset handler data
*
* NOTE: This code is copied to IRAM. All code and data accesses
* must be position-independent.
*/
.align L1_CACHE_SHIFT
ENTRY(__tegra_cpu_reset_handler)
cpsid aif, 0x13 @ SVC mode, interrupts disabled
mov32 r6, TEGRA_APB_MISC_BASE
ldr r6, [r6, #APB_MISC_GP_HIDREV]
and r6, r6, #0xff00
#ifdef CONFIG_ARCH_TEGRA_2x_SOC
t20_check:
cmp r6, #(0x20 << 8)
bne after_t20_check
t20_errata:
# Tegra20 is a Cortex-A9 r1p1
mrc p15, 0, r0, c1, c0, 0 @ read system control register
orr r0, r0, #1 << 14 @ erratum 716044
mcr p15, 0, r0, c1, c0, 0 @ write system control register
mrc p15, 0, r0, c15, c0, 1 @ read diagnostic register
orr r0, r0, #1 << 4 @ erratum 742230
orr r0, r0, #1 << 11 @ erratum 751472
mcr p15, 0, r0, c15, c0, 1 @ write diagnostic register
b after_errata
after_t20_check:
#endif
#ifdef CONFIG_ARCH_TEGRA_3x_SOC
t30_check:
cmp r6, #(0x30 << 8)
bne after_t30_check
t30_errata:
# Tegra30 is a Cortex-A9 r2p9
mrc p15, 0, r0, c15, c0, 1 @ read diagnostic register
orr r0, r0, #1 << 6 @ erratum 743622
orr r0, r0, #1 << 11 @ erratum 751472
mcr p15, 0, r0, c15, c0, 1 @ write diagnostic register
b after_errata
after_t30_check:
#endif
after_errata:
mrc p15, 0, r10, c0, c0, 5 @ MPIDR
and r10, r10, #0x3 @ R10 = CPU number
mov r11, #1
mov r11, r11, lsl r10 @ R11 = CPU mask
adr r12, __tegra_cpu_reset_handler_data
#ifdef CONFIG_SMP
/* Does the OS know about this CPU? */
ldr r7, [r12, #RESET_DATA(MASK_PRESENT)]
tst r7, r11 @ if !present
bleq __die @ CPU not present (to OS)
#endif
#ifdef CONFIG_ARCH_TEGRA_2x_SOC
/* Are we on Tegra20? */
cmp r6, #(0x20 << 8)
bne 1f
/* If not CPU0, don't let CPU0 reset CPU1 now that CPU1 is coming up. */
mov32 r5, TEGRA_PMC_BASE
mov r0, #0
cmp r10, #0
strne r0, [r5, #PMC_SCRATCH41]
1:
#endif
/* Waking up from LP2? */
ldr r9, [r12, #RESET_DATA(MASK_LP2)]
tst r9, r11 @ if in_lp2
beq __is_not_lp2
ldr lr, [r12, #RESET_DATA(STARTUP_LP2)]
cmp lr, #0
bleq __die @ no LP2 startup handler
bx lr
__is_not_lp2:
#ifdef CONFIG_SMP
/*
* Can only be secondary boot (initial or hotplug) but CPU 0
* cannot be here.
*/
cmp r10, #0
bleq __die @ CPU0 cannot be here
ldr lr, [r12, #RESET_DATA(STARTUP_SECONDARY)]
cmp lr, #0
bleq __die @ no secondary startup handler
bx lr
#endif
/*
* We don't know why the CPU reset. Just kill it.
* The LR register will contain the address we died at + 4.
*/
__die:
sub lr, lr, #4
mov32 r7, TEGRA_PMC_BASE
str lr, [r7, #PMC_SCRATCH41]
mov32 r7, TEGRA_CLK_RESET_BASE
/* Are we on Tegra20? */
mov32 r6, TEGRA_APB_MISC_BASE
ldr r0, [r6, #APB_MISC_GP_HIDREV]
and r0, r0, #0xff00
cmp r0, #(0x20 << 8)
bne 1f
#ifdef CONFIG_ARCH_TEGRA_2x_SOC
mov32 r0, 0x1111
mov r1, r0, lsl r10
str r1, [r7, #0x340] @ CLK_RST_CPU_CMPLX_SET
#endif
1:
#ifdef CONFIG_ARCH_TEGRA_3x_SOC
mov32 r6, TEGRA_FLOW_CTRL_BASE
cmp r10, #0
moveq r1, #FLOW_CTRL_HALT_CPU0_EVENTS
moveq r2, #FLOW_CTRL_CPU0_CSR
movne r1, r10, lsl #3
addne r2, r1, #(FLOW_CTRL_CPU1_CSR-8)
addne r1, r1, #(FLOW_CTRL_HALT_CPU1_EVENTS-8)
/* Clear CPU "event" and "interrupt" flags and power gate
it when halting but not before it is in the "WFI" state. */
ldr r0, [r6, +r2]
orr r0, r0, #FLOW_CTRL_CSR_INTR_FLAG | FLOW_CTRL_CSR_EVENT_FLAG
orr r0, r0, #FLOW_CTRL_CSR_ENABLE
str r0, [r6, +r2]
/* Unconditionally halt this CPU */
mov r0, #FLOW_CTRL_WAITEVENT
str r0, [r6, +r1]
ldr r0, [r6, +r1] @ memory barrier
dsb
isb
wfi @ CPU should be power gated here
/* If the CPU didn't power gate above just kill it's clock. */
mov r0, r11, lsl #8
str r0, [r7, #348] @ CLK_CPU_CMPLX_SET
#endif
/* If the CPU still isn't dead, just spin here. */
b .
ENDPROC(__tegra_cpu_reset_handler)
.align L1_CACHE_SHIFT
.type __tegra_cpu_reset_handler_data, %object
.globl __tegra_cpu_reset_handler_data
__tegra_cpu_reset_handler_data:
.rept TEGRA_RESET_DATA_SIZE
.long 0
.endr
.align L1_CACHE_SHIFT
ENTRY(__tegra_cpu_reset_handler_end)