u-boot/arch/arm/cpu/armv7/exynos/lowlevel_init.c
Doug Anderson 306f527eff Exynos: Fix L2 cache timings on Exynos5420 and Exynos5800
It was found that the L2 cache timings that we had before could cause
freezes and hangs.  We should make things more robust with better
timings.  Currently the production ChromeOS kernel applies these
timings, but it's nice to fixup firmware too (and upstream probably
won't take our kernel hacks).

This also provides a big cleanup of the L2 cache init code avoiding
some duplication.  The way things used to work:
* low_power_start() was installed by the SPL (both at boot and resume
  time) and left resident in iRAM for the kernel to use when bringing
  up additional CPUs.  It used configure_l2_ctlr() and
  configure_l2_actlr() when it detected it was on an A15.  This was
  needed (despite the L2 cache registers being shared among all A15s)
  because we might have been the first man in after the whole A15
  cluster was shutdown.
* secondary_cores_configure() was called on at boot time and at resume
  time.  Strangely this called configure_l2_ctlr() but not
  configure_l2_actlr() which was almost certainly wrong.  Given that
  we'll call both (see next bullet) later in the boot process it
  didn't matter for normal boot, but I guess this is how L2 cache
  settings got set on 5420/5800 (but not 5250?) at resume time.
* exynos5_set_l2cache_params() was called as part of cache enablement.
  This should happen at boot time (normally in the SPL except for USB
  boot where it happens in main U-Boot).

Note that the old code wasn't setting ECC/parity in the cache
enablement code but we happened to get it anyway because we'd call
secondary_cores_configure() at boot time.  For resume time we'd get it
anyway when the 2nd A15 core came up.

Let's make this a whole lot simpler.  Now we always set these
parameters in the same place for all boots and use the same code for
setting up secondary CPUs.

Intended net effects of this change (other than cleanup):
* Timings go from before:
    data: 0 cycle setup, 3 cycles (0x2) latency
    tag:  0 cycle setup, 3 cycles (0x2) latency
  after:
    data: 1 cycle setup, 4 cycles (0x3) latency
    tag:  1 cycle setup, 4 cycles (0x3) latency
* L2ACTLR is properly initted on 5420/5800 in all cases.

One note is that we're still relying on luck to keep low_power_start()
working.  The compiler is being nice and not storing anything on the
stack.

Another note is that on its own this patch won't help to fix cache
settings in an RW U-Boot update where we still have the RO SPL.  The
plan for that is:
* Have RW U-Boot re-init the cache right before calling the kernel
  (after it has turned the L2 cache off).  This is why the functions
  are in a header file instead of lowlevel_init.c.

* Have the kernel save the L2 cache settings of the boot CPU and apply
  them to all other CPUs.  We get a little lucky here because the old
  code was using "|=" to modify the registers and all of the bits that
  it's setting are also present in the new settings (!).  That means
  that when the 2nd CPU in the A15 cluster comes up it doesn't
  actually mess up the settings of the 1st CPU in the A15 cluster.  An
  alternative option is to have the kernel write its own
  low_power_start() code.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
2015-02-28 18:03:46 +09:00

224 lines
5.1 KiB
C

/*
* Lowlevel setup for EXYNOS5 based board
*
* Copyright (C) 2013 Samsung Electronics
* Rajeshwari Shinde <rajeshwari.s@samsung.com>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <config.h>
#include <asm/arch/cpu.h>
#include <asm/arch/dmc.h>
#include <asm/arch/power.h>
#include <asm/arch/tzpc.h>
#include <asm/arch/periph.h>
#include <asm/arch/pinmux.h>
#include <asm/arch/system.h>
#include <asm/armv7.h>
#include "common_setup.h"
#include "exynos5_setup.h"
/* These are the things we can do during low-level init */
enum {
DO_WAKEUP = 1 << 0,
DO_CLOCKS = 1 << 1,
DO_MEM_RESET = 1 << 2,
DO_UART = 1 << 3,
DO_POWER = 1 << 4,
};
#ifdef CONFIG_EXYNOS5420
/*
* Power up secondary CPUs.
*/
static void secondary_cpu_start(void)
{
v7_enable_smp(EXYNOS5420_INFORM_BASE);
svc32_mode_en();
branch_bx(CONFIG_EXYNOS_RELOCATE_CODE_BASE);
}
/*
* This is the entry point of hotplug-in and
* cluster switching.
*/
static void low_power_start(void)
{
uint32_t val, reg_val;
reg_val = readl(EXYNOS5420_SPARE_BASE);
if (reg_val != CPU_RST_FLAG_VAL) {
writel(0x0, CONFIG_LOWPOWER_FLAG);
branch_bx(0x0);
}
reg_val = readl(CONFIG_PHY_IRAM_BASE + 0x4);
if (reg_val != (uint32_t)&low_power_start) {
/* Store jump address as low_power_start if not present */
writel((uint32_t)&low_power_start, CONFIG_PHY_IRAM_BASE + 0x4);
dsb();
sev();
}
/* Set the CPU to SVC32 mode */
svc32_mode_en();
#ifndef CONFIG_SYS_L2CACHE_OFF
/* Read MIDR for Primary Part Number */
mrc_midr(val);
val = (val >> 4);
val &= 0xf;
if (val == 0xf) {
configure_l2_ctlr();
configure_l2_actlr();
v7_enable_l2_hazard_detect();
}
#endif
/* Invalidate L1 & TLB */
val = 0x0;
mcr_tlb(val);
mcr_icache(val);
/* Disable MMU stuff and caches */
mrc_sctlr(val);
val &= ~((0x2 << 12) | 0x7);
val |= ((0x1 << 12) | (0x8 << 8) | 0x2);
mcr_sctlr(val);
/* CPU state is hotplug or reset */
secondary_cpu_start();
/* Core should not enter into WFI here */
wfi();
}
/*
* Pointer to this function is stored in iRam which is used
* for jump and power down of a specific core.
*/
static void power_down_core(void)
{
uint32_t tmp, core_id, core_config;
/* Get the unique core id */
/*
* Multiprocessor Affinity Register
* [11:8] Cluster ID
* [1:0] CPU ID
*/
mrc_mpafr(core_id);
tmp = core_id & 0x3;
core_id = (core_id >> 6) & ~3;
core_id |= tmp;
core_id &= 0x3f;
/* Set the status of the core to low */
core_config = (core_id * CPU_CONFIG_STATUS_OFFSET);
core_config += EXYNOS5420_CPU_CONFIG_BASE;
writel(0x0, core_config);
/* Core enter WFI */
wfi();
}
/*
* Configurations for secondary cores are inapt at this stage.
* Reconfigure secondary cores. Shutdown and change the status
* of all cores except the primary core.
*/
static void secondary_cores_configure(void)
{
/* Clear secondary boot iRAM base */
writel(0x0, (CONFIG_EXYNOS_RELOCATE_CODE_BASE + 0x1C));
/* set lowpower flag and address */
writel(CPU_RST_FLAG_VAL, CONFIG_LOWPOWER_FLAG);
writel((uint32_t)&low_power_start, CONFIG_LOWPOWER_ADDR);
writel(CPU_RST_FLAG_VAL, EXYNOS5420_SPARE_BASE);
/* Store jump address for power down */
writel((uint32_t)&power_down_core, CONFIG_PHY_IRAM_BASE + 0x4);
/* Need all core power down check */
dsb();
sev();
}
extern void relocate_wait_code(void);
#endif
int do_lowlevel_init(void)
{
uint32_t reset_status;
int actions = 0;
arch_cpu_init();
#ifndef CONFIG_SYS_L2CACHE_OFF
/*
* Init L2 cache parameters here for use by boot and resume
*
* These are here instead of in v7_outer_cache_enable() so that the
* L2 cache settings get properly set even at resume time or if we're
* running U-Boot with the cache off. The kernel still needs us to
* set these for it.
*/
configure_l2_ctlr();
configure_l2_actlr();
dsb();
isb();
#endif
#ifdef CONFIG_EXYNOS5420
relocate_wait_code();
/* Reconfigure secondary cores */
secondary_cores_configure();
#endif
reset_status = get_reset_status();
switch (reset_status) {
case S5P_CHECK_SLEEP:
actions = DO_CLOCKS | DO_WAKEUP;
break;
case S5P_CHECK_DIDLE:
case S5P_CHECK_LPA:
actions = DO_WAKEUP;
break;
default:
/* This is a normal boot (not a wake from sleep) */
actions = DO_CLOCKS | DO_MEM_RESET | DO_POWER;
}
if (actions & DO_POWER)
set_ps_hold_ctrl();
if (actions & DO_CLOCKS) {
system_clock_init();
mem_ctrl_init(actions & DO_MEM_RESET);
tzpc_init();
}
return actions & DO_WAKEUP;
}