diff options
author | Brian Norris <computersforpeace@gmail.com> | 2014-12-16 19:13:50 -0800 |
---|---|---|
committer | Florian Fainelli <f.fainelli@gmail.com> | 2015-01-12 14:59:29 -0800 |
commit | a1ad3b94a7661b643fef2efbc6fc217bd148f462 (patch) | |
tree | a4521ca95d0be701ab8ee4c92d5e0bcbaa0e1414 /arch/arm/mach-bcm | |
parent | 97bf6af1f928216fd6c5a66e8a57bfa95a659672 (diff) | |
download | blackbird-op-linux-a1ad3b94a7661b643fef2efbc6fc217bd148f462.tar.gz blackbird-op-linux-a1ad3b94a7661b643fef2efbc6fc217bd148f462.zip |
ARM: brcmstb: update CPU power management sequence
The automatic CPU power state machine for B15 CPUs does not work
reliably as-is. This patch implements a manual sequence in software to
replace it.
This was tested successfully with over 10,000 hotplug cycles of
something like this:
echo 0 > /sys/devices/system/cpu/cpu1/online
echo 1 > /sys/devices/system/cpu/cpu1/online
whereas the existing sequence often locks up after a few hundred cycles.
Fixes: 62639c2f5332 ("ARM: brcmstb: reintroduce SMP support")
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Diffstat (limited to 'arch/arm/mach-bcm')
-rw-r--r-- | arch/arm/mach-bcm/platsmp-brcmstb.c | 85 |
1 files changed, 63 insertions, 22 deletions
diff --git a/arch/arm/mach-bcm/platsmp-brcmstb.c b/arch/arm/mach-bcm/platsmp-brcmstb.c index 31c87a284a34..e209e6fc7caf 100644 --- a/arch/arm/mach-bcm/platsmp-brcmstb.c +++ b/arch/arm/mach-bcm/platsmp-brcmstb.c @@ -17,6 +17,7 @@ #include <linux/errno.h> #include <linux/init.h> #include <linux/io.h> +#include <linux/jiffies.h> #include <linux/of_address.h> #include <linux/of_platform.h> #include <linux/printk.h> @@ -94,10 +95,35 @@ static u32 pwr_ctrl_rd(u32 cpu) return readl_relaxed(base); } -static void pwr_ctrl_wr(u32 cpu, u32 val) +static void pwr_ctrl_set(unsigned int cpu, u32 val, u32 mask) { void __iomem *base = pwr_ctrl_get_base(cpu); - writel(val, base); + writel((readl(base) & mask) | val, base); +} + +static void pwr_ctrl_clr(unsigned int cpu, u32 val, u32 mask) +{ + void __iomem *base = pwr_ctrl_get_base(cpu); + writel((readl(base) & mask) & ~val, base); +} + +#define POLL_TMOUT_MS 500 +static int pwr_ctrl_wait_tmout(unsigned int cpu, u32 set, u32 mask) +{ + const unsigned long timeo = jiffies + msecs_to_jiffies(POLL_TMOUT_MS); + u32 tmp; + + do { + tmp = pwr_ctrl_rd(cpu) & mask; + if (!set == !tmp) + return 0; + } while (time_before(jiffies, timeo)); + + tmp = pwr_ctrl_rd(cpu) & mask; + if (!set == !tmp) + return 0; + + return -ETIMEDOUT; } static void cpu_rst_cfg_set(u32 cpu, int set) @@ -139,15 +165,22 @@ static void brcmstb_cpu_power_on(u32 cpu) * The secondary cores power was cut, so we must go through * power-on initialization. */ - u32 tmp; + pwr_ctrl_set(cpu, ZONE_MAN_ISO_CNTL_MASK, 0xffffff00); + pwr_ctrl_set(cpu, ZONE_MANUAL_CONTROL_MASK, -1); + pwr_ctrl_set(cpu, ZONE_RESERVED_1_MASK, -1); - /* Request zone power up */ - pwr_ctrl_wr(cpu, ZONE_PWR_UP_REQ_MASK); + pwr_ctrl_set(cpu, ZONE_MAN_MEM_PWR_MASK, -1); - /* Wait for the power up FSM to complete */ - do { - tmp = pwr_ctrl_rd(cpu); - } while (!(tmp & ZONE_PWR_ON_STATE_MASK)); + if (pwr_ctrl_wait_tmout(cpu, 1, ZONE_MEM_PWR_STATE_MASK)) + panic("ZONE_MEM_PWR_STATE_MASK set timeout"); + + pwr_ctrl_set(cpu, ZONE_MAN_CLKEN_MASK, -1); + + if (pwr_ctrl_wait_tmout(cpu, 1, ZONE_DPG_PWR_STATE_MASK)) + panic("ZONE_DPG_PWR_STATE_MASK set timeout"); + + pwr_ctrl_clr(cpu, ZONE_MAN_ISO_CNTL_MASK, -1); + pwr_ctrl_set(cpu, ZONE_MAN_RESET_CNTL_MASK, -1); } static int brcmstb_cpu_get_power_state(u32 cpu) @@ -174,25 +207,33 @@ static void brcmstb_cpu_die(u32 cpu) static int brcmstb_cpu_kill(u32 cpu) { - u32 tmp; + /* + * Ordinarily, the hardware forbids power-down of CPU0 (which is good + * because it is the boot CPU), but this is not true when using BPCM + * manual mode. Consequently, we must avoid turning off CPU0 here to + * ensure that TI2C master reset will work. + */ + if (cpu == 0) { + pr_warn("SMP: refusing to power off CPU0\n"); + return 1; + } while (per_cpu_sw_state_rd(cpu)) ; - /* Program zone reset */ - pwr_ctrl_wr(cpu, ZONE_RESET_STATE_MASK | ZONE_BLK_RST_ASSERT_MASK | - ZONE_PWR_DN_REQ_MASK); + pwr_ctrl_set(cpu, ZONE_MANUAL_CONTROL_MASK, -1); + pwr_ctrl_clr(cpu, ZONE_MAN_RESET_CNTL_MASK, -1); + pwr_ctrl_clr(cpu, ZONE_MAN_CLKEN_MASK, -1); + pwr_ctrl_set(cpu, ZONE_MAN_ISO_CNTL_MASK, -1); + pwr_ctrl_clr(cpu, ZONE_MAN_MEM_PWR_MASK, -1); - /* Verify zone reset */ - tmp = pwr_ctrl_rd(cpu); - if (!(tmp & ZONE_RESET_STATE_MASK)) - pr_err("%s: Zone reset bit for CPU %d not asserted!\n", - __func__, cpu); + if (pwr_ctrl_wait_tmout(cpu, 0, ZONE_MEM_PWR_STATE_MASK)) + panic("ZONE_MEM_PWR_STATE_MASK clear timeout"); - /* Wait for power down */ - do { - tmp = pwr_ctrl_rd(cpu); - } while (!(tmp & ZONE_PWR_OFF_STATE_MASK)); + pwr_ctrl_clr(cpu, ZONE_RESERVED_1_MASK, -1); + + if (pwr_ctrl_wait_tmout(cpu, 0, ZONE_DPG_PWR_STATE_MASK)) + panic("ZONE_DPG_PWR_STATE_MASK clear timeout"); /* Flush pipeline before resetting CPU */ mb(); |