From: Finn Thain fthain@telegraphics.com.au
[ Upstream commit 5e3119e15fed5b9a9a7e528665ff098a4a8dbdbc ]
According to Freescale's documentation, MPC74XX processors have an erratum that prevents the TAU interrupt from working, so don't try to use it when running on those processors.
Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2") Signed-off-by: Finn Thain fthain@telegraphics.com.au Tested-by: Stan Johnson userm57@yahoo.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/c281611544768e758bd58fe812cf702a5bd2d042.159926054... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/tau_6xx.c | 33 ++++++++++++++------------------- arch/powerpc/platforms/Kconfig | 5 ++--- 2 files changed, 16 insertions(+), 22 deletions(-)
diff --git a/arch/powerpc/kernel/tau_6xx.c b/arch/powerpc/kernel/tau_6xx.c index b8d7e7d498e0a..614b5b272d9c6 100644 --- a/arch/powerpc/kernel/tau_6xx.c +++ b/arch/powerpc/kernel/tau_6xx.c @@ -40,6 +40,8 @@ static struct tau_temp unsigned char grew; } tau[NR_CPUS];
+static bool tau_int_enable; + #undef DEBUG
/* TODO: put these in a /proc interface, with some sanity checks, and maybe @@ -54,22 +56,13 @@ static struct tau_temp
static void set_thresholds(unsigned long cpu) { -#ifdef CONFIG_TAU_INT - /* - * setup THRM1, - * threshold, valid bit, enable interrupts, interrupt when below threshold - */ - mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | THRM1_TIE | THRM1_TID); + u32 maybe_tie = tau_int_enable ? THRM1_TIE : 0;
- /* setup THRM2, - * threshold, valid bit, enable interrupts, interrupt when above threshold - */ - mtspr (SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V | THRM1_TIE); -#else - /* same thing but don't enable interrupts */ - mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | THRM1_TID); - mtspr(SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V); -#endif + /* setup THRM1, threshold, valid bit, interrupt when below threshold */ + mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | maybe_tie | THRM1_TID); + + /* setup THRM2, threshold, valid bit, interrupt when above threshold */ + mtspr(SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V | maybe_tie); }
static void TAUupdate(int cpu) @@ -142,9 +135,8 @@ static void tau_timeout(void * info) local_irq_save(flags); cpu = smp_processor_id();
-#ifndef CONFIG_TAU_INT - TAUupdate(cpu); -#endif + if (!tau_int_enable) + TAUupdate(cpu);
size = tau[cpu].high - tau[cpu].low; if (size > min_window && ! tau[cpu].grew) { @@ -225,6 +217,9 @@ static int __init TAU_init(void) return 1; }
+ tau_int_enable = IS_ENABLED(CONFIG_TAU_INT) && + !strcmp(cur_cpu_spec->platform, "ppc750"); + tau_workq = alloc_workqueue("tau", WQ_UNBOUND, 1, 0); if (!tau_workq) return -ENOMEM; @@ -234,7 +229,7 @@ static int __init TAU_init(void) queue_work(tau_workq, &tau_work);
pr_info("Thermal assist unit using %s, shrink_timer: %d ms\n", - IS_ENABLED(CONFIG_TAU_INT) ? "interrupts" : "workqueue", shrink_timer); + tau_int_enable ? "interrupts" : "workqueue", shrink_timer); tau_initialized = 1;
return 0; diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig index 14ef17e10ec9a..e094211c7206b 100644 --- a/arch/powerpc/platforms/Kconfig +++ b/arch/powerpc/platforms/Kconfig @@ -238,9 +238,8 @@ config TAU temperature within 2-4 degrees Celsius. This option shows the current on-die temperature in /proc/cpuinfo if the cpu supports it.
- Unfortunately, on some chip revisions, this sensor is very inaccurate - and in many cases, does not work at all, so don't assume the cpu - temp is actually what /proc/cpuinfo says it is. + Unfortunately, this sensor is very inaccurate when uncalibrated, so + don't assume the cpu temp is actually what /proc/cpuinfo says it is.
config TAU_INT bool "Interrupt driven TAU driver (DANGEROUS)"