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powerpc: Hook up doorbells on server

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This patch actually hooks up doorbell interrupts on POWER8:

- Select the PPC_DOORBELL Kconfig option from PPC_PSERIES

- Add the doorbell CPU feature bit to POWER8

- We define a new pSeries_cause_ipi_mux() function that issues a
  doorbell interrupt if the recipient is another thread within the same
  core as the sender. If the recipient is in a different core it falls
  back to using XICS to deliver the IPI as before.

- During pSeries_smp_probe() at boot, we check if doorbell interrupts
  are supported. If they are we set the cause_ipi function pointer to
  the above mentioned function, otherwise we leave it as whichever XICS
  cause_ipi function was determined by xics_smp_probe().

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Tested-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Ian Munsie 2012-11-14 18:49:50 +00:00 committed by Benjamin Herrenschmidt
parent 440bc68553
commit e5e84f0a66
3 changed files with 34 additions and 3 deletions
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3
arch/powerpc/include/asm/cputable.h
View File

@ -408,7 +408,8 @@ extern const char *powerpc_base_platform;
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
CPU_FTR_DSCR | CPU_FTR_SAO | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_ICSWX | CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY)
CPU_FTR_ICSWX | CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL)
#define CPU_FTRS_CELL (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \
CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \

1
arch/powerpc/platforms/pseries/Kconfig
View File

@ -17,6 +17,7 @@ config PPC_PSERIES
select PPC_NATIVE
select PPC_PCI_CHOICE if EXPERT
select ZLIB_DEFLATE
select PPC_DOORBELL
default y
config PPC_SPLPAR

33
arch/powerpc/platforms/pseries/smp.c
View File

@ -42,6 +42,7 @@
#include <asm/vdso_datapage.h>
#include <asm/cputhreads.h>
#include <asm/xics.h>
#include <asm/dbell.h>
#include "plpar_wrappers.h"
#include "pseries.h"
@ -54,6 +55,11 @@
*/
static cpumask_var_t of_spin_mask;
/*
* If we multiplex IPI mechanisms, store the appropriate XICS IPI mechanism here
*/
static void (*xics_cause_ipi)(int cpu, unsigned long data);
/* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */
int smp_query_cpu_stopped(unsigned int pcpu)
{
@ -137,6 +143,8 @@ static void smp_xics_setup_cpu(int cpu)
{
if (cpu != boot_cpuid)
xics_setup_cpu();
if (cpu_has_feature(CPU_FTR_DBELL))
doorbell_setup_this_cpu();
if (firmware_has_feature(FW_FEATURE_SPLPAR))
vpa_init(cpu);
@ -195,6 +203,27 @@ static int smp_pSeries_cpu_bootable(unsigned int nr)
return 1;
}
/* Only used on systems that support multiple IPI mechanisms */
static void pSeries_cause_ipi_mux(int cpu, unsigned long data)
{
if (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id())))
doorbell_cause_ipi(cpu, data);
else
xics_cause_ipi(cpu, data);
}
static __init int pSeries_smp_probe(void)
{
int ret = xics_smp_probe();
if (cpu_has_feature(CPU_FTR_DBELL)) {
xics_cause_ipi = smp_ops->cause_ipi;
smp_ops->cause_ipi = pSeries_cause_ipi_mux;
}
return ret;
}
static struct smp_ops_t pSeries_mpic_smp_ops = {
.message_pass = smp_mpic_message_pass,
.probe = smp_mpic_probe,
@ -204,8 +233,8 @@ static struct smp_ops_t pSeries_mpic_smp_ops = {
static struct smp_ops_t pSeries_xics_smp_ops = {
.message_pass = NULL, /* Use smp_muxed_ipi_message_pass */
.cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */
.probe = xics_smp_probe,
.cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */
.probe = pSeries_smp_probe,
.kick_cpu = smp_pSeries_kick_cpu,
.setup_cpu = smp_xics_setup_cpu,
.cpu_bootable = smp_pSeries_cpu_bootable,