| Message ID | 1310053830-23779-13-git-send-email-lorenzo.pieralisi@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 7/7/2011 8:50 AM, Lorenzo Pieralisi wrote: > When a CLUSTER is powered down the SCU must be reinitialized on > warm-boot. > This patch adds a hook to reset the SCU, which implies invalidating > TAG RAMs and renabling it. > > The scu virtual address is saved in a static variable when the SCU > is first enabled at boot; this allows common idle code to be > generic and avoid relying on platform code to get the address at > run-time. > On warm-boot the SCU TAG RAM is invalidated and the SCU enabled if > it is not already enabled. > > The reset can be skipped altogether thanks to save/restore > framework flags. > > Flushing D$ cache is cumbersome since the system just comes out of > reset, which invalidates caches in the process if needed (A9), that > is why the scu_enable function is not reused as it is to reset the SCU. > > If the init function is extended, there might not be a need for > a SCU specific hook, since the init function can be reused to > reinitialize the SCU at boot provided it is removed from the init > section and kept in memory. > > Signed-off-by: Lorenzo Pieralisi<lorenzo.pieralisi@arm.com> > --- > arch/arm/include/asm/smp_scu.h | 3 ++- > arch/arm/kernel/smp_scu.c | 33 ++++++++++++++++++++++++++++++--- > 2 files changed, 32 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h > index 4eb6d00..cfaa68e 100644 > --- a/arch/arm/include/asm/smp_scu.h > +++ b/arch/arm/include/asm/smp_scu.h > @@ -8,7 +8,8 @@ > #ifndef __ASSEMBLER__ > unsigned int scu_get_core_count(void __iomem *); > void scu_enable(void __iomem *); > -int scu_power_mode(void __iomem *, unsigned int); > +int scu_power_mode(unsigned int); > +void scu_reset(void); > #endif > > #endif > diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c > index a1e757c..980ced9 100644 > --- a/arch/arm/kernel/smp_scu.c > +++ b/arch/arm/kernel/smp_scu.c > @@ -20,6 +20,7 @@ > #define SCU_INVALIDATE 0x0c > #define SCU_FPGA_REVISION 0x10 > > +static void __iomem *scu_va; Change log and patch doesn't seems to match. I remember suggesting this change to Russell when "scu_power_mode()" was introduced. His preference was to have scu_base passed as part of the API. > /* > * Get the number of CPU cores from the SCU configuration > */ > @@ -36,6 +37,7 @@ void __init scu_enable(void __iomem *scu_base) > { > u32 scu_ctrl; > > + scu_va = scu_base; > scu_ctrl = __raw_readl(scu_base + SCU_CTRL); > /* already enabled? */ > if (scu_ctrl& 1) > @@ -59,7 +61,7 @@ void __init scu_enable(void __iomem *scu_base) > * has the side effect of disabling coherency, caches must have been > * flushed. Interrupts must also have been disabled. > */ > -int scu_power_mode(void __iomem *scu_base, unsigned int mode) > +int scu_power_mode(unsigned int mode) > { > unsigned int val; > int cpu = smp_processor_id(); > @@ -67,9 +69,34 @@ int scu_power_mode(void __iomem *scu_base, unsigned int mode) > if (mode> 3 || mode == 1 || cpu> 3) > return -EINVAL; > > - val = __raw_readb(scu_base + SCU_CPU_STATUS + cpu)& ~0x03; > + val = __raw_readb(scu_va + SCU_CPU_STATUS + cpu)& ~0x03; > val |= mode; > - __raw_writeb(val, scu_base + SCU_CPU_STATUS + cpu); > + __raw_writeb(val, scu_va + SCU_CPU_STATUS + cpu); > > return 0; > } > + > +/* > + * Reinitialise the SCU after power-down > + */ > + > +void scu_reset(void) > +{ > + u32 scu_ctrl; > + > + scu_ctrl = __raw_readl(scu_va + SCU_CTRL); > + /* already enabled? */ > + if (scu_ctrl& 1) > + return; > + /* > + * SCU TAGS should be invalidated on boot-up > + */ > + __raw_writel(0xffff, scu_va + SCU_INVALIDATE); > + /* > + * Coming out of reset, dcache invalidated > + * no need to go through the whole hog again > + * just enable the SCU and pop out > + */ > + scu_ctrl |= 1; > + __raw_writel(scu_ctrl, scu_va + SCU_CTRL); > +}
diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h index 4eb6d00..cfaa68e 100644 --- a/arch/arm/include/asm/smp_scu.h +++ b/arch/arm/include/asm/smp_scu.h @@ -8,7 +8,8 @@ #ifndef __ASSEMBLER__ unsigned int scu_get_core_count(void __iomem *); void scu_enable(void __iomem *); -int scu_power_mode(void __iomem *, unsigned int); +int scu_power_mode(unsigned int); +void scu_reset(void); #endif #endif diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c index a1e757c..980ced9 100644 --- a/arch/arm/kernel/smp_scu.c +++ b/arch/arm/kernel/smp_scu.c @@ -20,6 +20,7 @@ #define SCU_INVALIDATE 0x0c #define SCU_FPGA_REVISION 0x10 +static void __iomem *scu_va; /* * Get the number of CPU cores from the SCU configuration */ @@ -36,6 +37,7 @@ void __init scu_enable(void __iomem *scu_base) { u32 scu_ctrl; + scu_va = scu_base; scu_ctrl = __raw_readl(scu_base + SCU_CTRL); /* already enabled? */ if (scu_ctrl & 1) @@ -59,7 +61,7 @@ void __init scu_enable(void __iomem *scu_base) * has the side effect of disabling coherency, caches must have been * flushed. Interrupts must also have been disabled. */ -int scu_power_mode(void __iomem *scu_base, unsigned int mode) +int scu_power_mode(unsigned int mode) { unsigned int val; int cpu = smp_processor_id(); @@ -67,9 +69,34 @@ int scu_power_mode(void __iomem *scu_base, unsigned int mode) if (mode > 3 || mode == 1 || cpu > 3) return -EINVAL; - val = __raw_readb(scu_base + SCU_CPU_STATUS + cpu) & ~0x03; + val = __raw_readb(scu_va + SCU_CPU_STATUS + cpu) & ~0x03; val |= mode; - __raw_writeb(val, scu_base + SCU_CPU_STATUS + cpu); + __raw_writeb(val, scu_va + SCU_CPU_STATUS + cpu); return 0; } + +/* + * Reinitialise the SCU after power-down + */ + +void scu_reset(void) +{ + u32 scu_ctrl; + + scu_ctrl = __raw_readl(scu_va + SCU_CTRL); + /* already enabled? */ + if (scu_ctrl & 1) + return; + /* + * SCU TAGS should be invalidated on boot-up + */ + __raw_writel(0xffff, scu_va + SCU_INVALIDATE); + /* + * Coming out of reset, dcache invalidated + * no need to go through the whole hog again + * just enable the SCU and pop out + */ + scu_ctrl |= 1; + __raw_writel(scu_ctrl, scu_va + SCU_CTRL); +}
When a CLUSTER is powered down the SCU must be reinitialized on warm-boot. This patch adds a hook to reset the SCU, which implies invalidating TAG RAMs and renabling it. The scu virtual address is saved in a static variable when the SCU is first enabled at boot; this allows common idle code to be generic and avoid relying on platform code to get the address at run-time. On warm-boot the SCU TAG RAM is invalidated and the SCU enabled if it is not already enabled. The reset can be skipped altogether thanks to save/restore framework flags. Flushing D$ cache is cumbersome since the system just comes out of reset, which invalidates caches in the process if needed (A9), that is why the scu_enable function is not reused as it is to reset the SCU. If the init function is extended, there might not be a need for a SCU specific hook, since the init function can be reused to reinitialize the SCU at boot provided it is removed from the init section and kept in memory. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> --- arch/arm/include/asm/smp_scu.h | 3 ++- arch/arm/kernel/smp_scu.c | 33 ++++++++++++++++++++++++++++++--- 2 files changed, 32 insertions(+), 4 deletions(-)