Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-10-30 08:42:47 +00:00
Code Issues Packages Projects Releases Wiki Activity

MIPS: smp-cps: Add support for CPU hotplug of MIPSr6 processors

Browse Source 
Introduce support for hotplug of Virtual Processors in MIPSr6 systems.
The method is simpler than the VPE parallel from the now-deprecated MT
ASE, it can now simply write the VP_STOP register with the mask of VPs
to halt, and use the VP_RUNNING register to determine when the VP has
halted.

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13752/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Matt Redfearn 2016-07-07 08:50:39 +01:00 committed by Ralf Baechle
parent 9736c6152e
commit 0d2808f338
1 changed files with 27 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
arch/mips/kernel/smp-cps.c
View File

@ -412,14 +412,16 @@ static enum {
void play_dead(void)
{
unsigned cpu, core;
unsigned int cpu, core, vpe_id;
local_irq_disable();
idle_task_exit();
cpu = smp_processor_id();
cpu_death = CPU_DEATH_POWER;
if (cpu_has_mipsmt) {
pr_debug("CPU%d going offline\n", cpu);
if (cpu_has_mipsmt || cpu_has_vp) {
core = cpu_data[cpu].core;
/* Look for another online VPE within the core */
@ -440,10 +442,21 @@ void play_dead(void)
complete(&cpu_death_chosen);
if (cpu_death == CPU_DEATH_HALT) {
/* Halt this TC */
write_c0_tchalt(TCHALT_H);
instruction_hazard();
vpe_id = cpu_vpe_id(&cpu_data[cpu]);
pr_debug("Halting core %d VP%d\n", core, vpe_id);
if (cpu_has_mipsmt) {
/* Halt this TC */
write_c0_tchalt(TCHALT_H);
instruction_hazard();
} else if (cpu_has_vp) {
write_cpc_cl_vp_stop(1 << vpe_id);
/* Ensure that the VP_STOP register is written */
wmb();
}
} else {
pr_debug("Gating power to core %d\n", core);
/* Power down the core */
cps_pm_enter_state(CPS_PM_POWER_GATED);
}
@ -470,6 +483,7 @@ static void wait_for_sibling_halt(void *ptr_cpu)
static void cps_cpu_die(unsigned int cpu)
{
unsigned core = cpu_data[cpu].core;
unsigned int vpe_id = cpu_vpe_id(&cpu_data[cpu]);
unsigned stat;
int err;
@ -498,10 +512,12 @@ static void cps_cpu_die(unsigned int cpu)
* in which case the CPC will refuse to power down the core.
*/
do {
mips_cm_lock_other(core, vpe_id);
mips_cpc_lock_other(core);
stat = read_cpc_co_stat_conf();
stat &= CPC_Cx_STAT_CONF_SEQSTATE_MSK;
mips_cpc_unlock_other();
mips_cm_unlock_other();
} while (stat != CPC_Cx_STAT_CONF_SEQSTATE_D0 &&
stat != CPC_Cx_STAT_CONF_SEQSTATE_D2 &&
stat != CPC_Cx_STAT_CONF_SEQSTATE_U2);
@ -518,6 +534,12 @@ static void cps_cpu_die(unsigned int cpu)
(void *)(unsigned long)cpu, 1);
if (err)
panic("Failed to call remote sibling CPU\n");
} else if (cpu_has_vp) {
do {
mips_cm_lock_other(core, vpe_id);
stat = read_cpc_co_vp_running();
mips_cm_unlock_other();
} while (stat & (1 << vpe_id));
}
}