The etm4_enable_trace_unit() function is almost identical to the restore flow, with a few differences listed below:
1) TRCQCTLR register
The TRCQCTLR register is saved and restored during CPU idle, but it is never touched in the normal flow. Given the Q element is not enabled (TRCCONFIGR.QE bits), it is acceptable to omit saving and restoring this register during idle.
2) TRCSSCSRn.STATUS bit
The restore flow does not explicitly clear the TRCSSCSRn.STATUS bit but instead directly loads the saved value. In contrast, the normal flow clears this bit to 0 when re-enabling single-shot control.
Therefore, the restore function passes the restart_ss argument as false to etm4_enable_hw() to avoid re-enabling single-shot mode.
3) Claim Tag Handling
The claim tag is acquired and released in normal flow, on the other hand, the claim protocol is not applied in CPU idle flow - it simply restores the saved value.
The claim bits serve two purpose:
* Exclusive access between the kernel driver and an external debugger. During CPU idle, the kernel driver locks the OS Lock, ensuring that the external debugger cannot access the trace unit. Therefore, it is safe to release the claim tag during idle.
* Notification to supervisory software to save/restore context for external debuggers. The kernel driver does not touch the external debugger's claim bit (ETMCLAIM[0]).
Based on this, it is safe to acquire and release claim tag in the idle sequence.
4) OS Lock Behavior
The OS Lock should be locked during CPU idle states. This differs from the normal flow, which unlock it. This special handling remains in the CPU save path.
This commit reuses the normal enable and disable logic in the CPU idle path. The only addition is locking the OS Lock upon entering idle to ensure exclusive access.
The save context in the driver data is no longer needed and has been removed.
Tested-by: James Clark james.clark@linaro.org Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 215 +-------------------- drivers/hwtracing/coresight/coresight-etm4x.h | 57 ------ 2 files changed, 5 insertions(+), 267 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 71a4fcbca44091d5f441d4bc502b3c5f4fd3c984..6cfcede7e87846727bc040069399f7f9bb2e1abc 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1856,8 +1856,7 @@ static int etm4_dying_cpu(unsigned int cpu)
static int __etm4_cpu_save(struct etmv4_drvdata *drvdata) { - int i, ret = 0; - struct etmv4_save_state *state; + int ret = 0; struct coresight_device *csdev = drvdata->csdev; struct csdev_access *csa; struct device *etm_dev; @@ -1887,100 +1886,11 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata) ret = -EBUSY; goto out; } + etm4_cs_lock(drvdata, csa);
- if (!drvdata->paused) - etm4_disable_trace_unit(drvdata); - - /* - * As recommended by section 4.3.7 (Synchronization of register updates) - * of ARM IHI 0064H.b, the self-hosted trace analyzer always executes an - * ISB instruction after programming the trace unit registers. - */ - isb(); - - state = drvdata->save_state; - - if (drvdata->nr_pe) - state->trcprocselr = etm4x_read32(csa, TRCPROCSELR); - state->trcconfigr = etm4x_read32(csa, TRCCONFIGR); - state->trcauxctlr = etm4x_read32(csa, TRCAUXCTLR); - state->trceventctl0r = etm4x_read32(csa, TRCEVENTCTL0R); - state->trceventctl1r = etm4x_read32(csa, TRCEVENTCTL1R); - if (drvdata->stallctl) - state->trcstallctlr = etm4x_read32(csa, TRCSTALLCTLR); - state->trctsctlr = etm4x_read32(csa, TRCTSCTLR); - state->trcsyncpr = etm4x_read32(csa, TRCSYNCPR); - state->trcccctlr = etm4x_read32(csa, TRCCCCTLR); - state->trcbbctlr = etm4x_read32(csa, TRCBBCTLR); - state->trctraceidr = etm4x_read32(csa, TRCTRACEIDR); - if (drvdata->q_filt) - state->trcqctlr = etm4x_read32(csa, TRCQCTLR); - - state->trcvictlr = etm4x_read32(csa, TRCVICTLR); - state->trcviiectlr = etm4x_read32(csa, TRCVIIECTLR); - state->trcvissctlr = etm4x_read32(csa, TRCVISSCTLR); - if (drvdata->nr_pe_cmp) - state->trcvipcssctlr = etm4x_read32(csa, TRCVIPCSSCTLR); - - for (i = 0; i < drvdata->nrseqstate - 1; i++) - state->trcseqevr[i] = etm4x_read32(csa, TRCSEQEVRn(i)); - - if (drvdata->nrseqstate) { - state->trcseqrstevr = etm4x_read32(csa, TRCSEQRSTEVR); - state->trcseqstr = etm4x_read32(csa, TRCSEQSTR); - } - - if (drvdata->numextinsel) - state->trcextinselr = etm4x_read32(csa, TRCEXTINSELR); - - for (i = 0; i < drvdata->nr_cntr; i++) { - state->trccntrldvr[i] = etm4x_read32(csa, TRCCNTRLDVRn(i)); - state->trccntctlr[i] = etm4x_read32(csa, TRCCNTCTLRn(i)); - state->trccntvr[i] = etm4x_read32(csa, TRCCNTVRn(i)); - } - - /* Resource selector pair 0 is reserved */ - for (i = 2; i < drvdata->nr_resource * 2; i++) - state->trcrsctlr[i] = etm4x_read32(csa, TRCRSCTLRn(i)); - - for (i = 0; i < drvdata->nr_ss_cmp; i++) { - state->trcssccr[i] = etm4x_read32(csa, TRCSSCCRn(i)); - state->trcsscsr[i] = etm4x_read32(csa, TRCSSCSRn(i)); - if (etm4x_sspcicrn_present(drvdata, i)) - state->trcsspcicr[i] = etm4x_read32(csa, TRCSSPCICRn(i)); - } - - for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) { - state->trcacvr[i] = etm4x_read64(csa, TRCACVRn(i)); - state->trcacatr[i] = etm4x_read64(csa, TRCACATRn(i)); - } - - /* - * Data trace stream is architecturally prohibited for A profile cores - * so we don't save (or later restore) trcdvcvr and trcdvcmr - As per - * section 1.3.4 ("Possible functional configurations of an ETMv4 trace - * unit") of ARM IHI 0064D. - */ - - for (i = 0; i < drvdata->numcidc; i++) - state->trccidcvr[i] = etm4x_read64(csa, TRCCIDCVRn(i)); - - for (i = 0; i < drvdata->numvmidc; i++) - state->trcvmidcvr[i] = etm4x_read64(csa, TRCVMIDCVRn(i)); - - state->trccidcctlr0 = etm4x_read32(csa, TRCCIDCCTLR0); - if (drvdata->numcidc > 4) - state->trccidcctlr1 = etm4x_read32(csa, TRCCIDCCTLR1); - - state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR0); - if (drvdata->numvmidc > 4) - state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR1); - - state->trcclaimset = etm4x_read32(csa, TRCCLAIMCLR); - - if (!drvdata->skip_power_up) - state->trcpdcr = etm4x_read32(csa, TRCPDCR); + etm4_disable_hw(drvdata);
+ etm4_cs_unlock(drvdata, csa); /* wait for TRCSTATR.IDLE to go up */ if (etm4x_wait_status(csa, TRCSTATR_IDLE_BIT, 1)) { dev_err(etm_dev, @@ -1990,14 +1900,6 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata) goto out; }
- /* - * Power can be removed from the trace unit now. We do this to - * potentially save power on systems that respect the TRCPDCR_PU - * despite requesting software to save/restore state. - */ - if (!drvdata->skip_power_up) - etm4x_relaxed_write32(csa, (state->trcpdcr & ~TRCPDCR_PU), - TRCPDCR); out: etm4_cs_lock(drvdata, csa); return ret; @@ -2021,110 +1923,10 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata) { - int i; - struct etmv4_save_state *state = drvdata->save_state; - struct csdev_access *csa = &drvdata->csdev->access; - if (WARN_ON(!drvdata->csdev)) return;
- etm4_cs_unlock(drvdata, csa); - etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET); - - if (drvdata->nr_pe) - etm4x_relaxed_write32(csa, state->trcprocselr, TRCPROCSELR); - etm4x_relaxed_write32(csa, state->trcconfigr, TRCCONFIGR); - etm4x_relaxed_write32(csa, state->trcauxctlr, TRCAUXCTLR); - etm4x_relaxed_write32(csa, state->trceventctl0r, TRCEVENTCTL0R); - etm4x_relaxed_write32(csa, state->trceventctl1r, TRCEVENTCTL1R); - if (drvdata->stallctl) - etm4x_relaxed_write32(csa, state->trcstallctlr, TRCSTALLCTLR); - etm4x_relaxed_write32(csa, state->trctsctlr, TRCTSCTLR); - etm4x_relaxed_write32(csa, state->trcsyncpr, TRCSYNCPR); - etm4x_relaxed_write32(csa, state->trcccctlr, TRCCCCTLR); - etm4x_relaxed_write32(csa, state->trcbbctlr, TRCBBCTLR); - etm4x_relaxed_write32(csa, state->trctraceidr, TRCTRACEIDR); - if (drvdata->q_filt) - etm4x_relaxed_write32(csa, state->trcqctlr, TRCQCTLR); - - etm4x_relaxed_write32(csa, state->trcvictlr, TRCVICTLR); - etm4x_relaxed_write32(csa, state->trcviiectlr, TRCVIIECTLR); - etm4x_relaxed_write32(csa, state->trcvissctlr, TRCVISSCTLR); - if (drvdata->nr_pe_cmp) - etm4x_relaxed_write32(csa, state->trcvipcssctlr, TRCVIPCSSCTLR); - - for (i = 0; i < drvdata->nrseqstate - 1; i++) - etm4x_relaxed_write32(csa, state->trcseqevr[i], TRCSEQEVRn(i)); - - if (drvdata->nrseqstate) { - etm4x_relaxed_write32(csa, state->trcseqrstevr, TRCSEQRSTEVR); - etm4x_relaxed_write32(csa, state->trcseqstr, TRCSEQSTR); - } - if (drvdata->numextinsel) - etm4x_relaxed_write32(csa, state->trcextinselr, TRCEXTINSELR); - - for (i = 0; i < drvdata->nr_cntr; i++) { - etm4x_relaxed_write32(csa, state->trccntrldvr[i], TRCCNTRLDVRn(i)); - etm4x_relaxed_write32(csa, state->trccntctlr[i], TRCCNTCTLRn(i)); - etm4x_relaxed_write32(csa, state->trccntvr[i], TRCCNTVRn(i)); - } - - /* Resource selector pair 0 is reserved */ - for (i = 2; i < drvdata->nr_resource * 2; i++) - etm4x_relaxed_write32(csa, state->trcrsctlr[i], TRCRSCTLRn(i)); - - for (i = 0; i < drvdata->nr_ss_cmp; i++) { - etm4x_relaxed_write32(csa, state->trcssccr[i], TRCSSCCRn(i)); - etm4x_relaxed_write32(csa, state->trcsscsr[i], TRCSSCSRn(i)); - if (etm4x_sspcicrn_present(drvdata, i)) - etm4x_relaxed_write32(csa, state->trcsspcicr[i], TRCSSPCICRn(i)); - } - - for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) { - etm4x_relaxed_write64(csa, state->trcacvr[i], TRCACVRn(i)); - etm4x_relaxed_write64(csa, state->trcacatr[i], TRCACATRn(i)); - } - - for (i = 0; i < drvdata->numcidc; i++) - etm4x_relaxed_write64(csa, state->trccidcvr[i], TRCCIDCVRn(i)); - - for (i = 0; i < drvdata->numvmidc; i++) - etm4x_relaxed_write64(csa, state->trcvmidcvr[i], TRCVMIDCVRn(i)); - - etm4x_relaxed_write32(csa, state->trccidcctlr0, TRCCIDCCTLR0); - if (drvdata->numcidc > 4) - etm4x_relaxed_write32(csa, state->trccidcctlr1, TRCCIDCCTLR1); - - etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR0); - if (drvdata->numvmidc > 4) - etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR1); - - etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET); - - if (!drvdata->skip_power_up) - etm4x_relaxed_write32(csa, state->trcpdcr, TRCPDCR); - - /* - * As recommended by section 4.3.7 ("Synchronization when using the - * memory-mapped interface") of ARM IHI 0064D - */ - dsb(sy); - isb(); - - /* Unlock the OS lock to re-enable trace and external debug access */ - etm4_os_unlock(drvdata); - - if (!drvdata->paused) - etm4_enable_trace_unit(drvdata); - - /* - * As recommended by section 4.3.7 (Synchronization of register updates) - * of ARM IHI 0064H.b, the self-hosted trace analyzer always executes an - * ISB instruction after programming the trace unit registers. - */ - isb(); - - etm4_cs_lock(drvdata, csa); + etm4_enable_hw(drvdata, false); }
static void etm4_cpu_restore(struct etmv4_drvdata *drvdata) @@ -2311,13 +2113,6 @@ static int etm4_probe(struct device *dev) pm_save_enable = coresight_loses_context_with_cpu(dev) ? PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER;
- if (pm_save_enable != PARAM_PM_SAVE_NEVER) { - drvdata->save_state = devm_kmalloc(dev, - sizeof(struct etmv4_save_state), GFP_KERNEL); - if (!drvdata->save_state) - return -ENOMEM; - } - raw_spin_lock_init(&drvdata->spinlock);
drvdata->cpu = coresight_get_cpu(dev); diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index 012c52fd19338133129752d35523dc102df24604..9dfdcfc2b16748bedc278ba2ceaa7e39b29cc351 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -862,61 +862,6 @@ struct etmv4_config { u8 s_ex_level; };
-/** - * struct etm4_save_state - state to be preserved when ETM is without power - */ -struct etmv4_save_state { - u32 trcprocselr; - u32 trcconfigr; - u32 trcauxctlr; - u32 trceventctl0r; - u32 trceventctl1r; - u32 trcstallctlr; - u32 trctsctlr; - u32 trcsyncpr; - u32 trcccctlr; - u32 trcbbctlr; - u32 trctraceidr; - u32 trcqctlr; - - u32 trcvictlr; - u32 trcviiectlr; - u32 trcvissctlr; - u32 trcvipcssctlr; - - u32 trcseqevr[ETM_MAX_SEQ_STATES]; - u32 trcseqrstevr; - u32 trcseqstr; - u32 trcextinselr; - u32 trccntrldvr[ETMv4_MAX_CNTR]; - u32 trccntctlr[ETMv4_MAX_CNTR]; - u32 trccntvr[ETMv4_MAX_CNTR]; - - u32 trcrsctlr[ETM_MAX_RES_SEL]; - - u32 trcssccr[ETM_MAX_SS_CMP]; - u32 trcsscsr[ETM_MAX_SS_CMP]; - u32 trcsspcicr[ETM_MAX_SS_CMP]; - - u64 trcacvr[ETM_MAX_SINGLE_ADDR_CMP]; - u64 trcacatr[ETM_MAX_SINGLE_ADDR_CMP]; - u64 trccidcvr[ETMv4_MAX_CTXID_CMP]; - u64 trcvmidcvr[ETM_MAX_VMID_CMP]; - u32 trccidcctlr0; - u32 trccidcctlr1; - u32 trcvmidcctlr0; - u32 trcvmidcctlr1; - - u32 trcclaimset; - - u32 cntr_val[ETMv4_MAX_CNTR]; - u32 seq_state; - u32 vinst_ctrl; - u32 ss_status[ETM_MAX_SS_CMP]; - - u32 trcpdcr; -}; - /** * struct etm4_drvdata - specifics associated to an ETM component * @pclk: APB clock if present, otherwise NULL @@ -979,7 +924,6 @@ struct etmv4_save_state { * at runtime, due to the additional setting of TRFCR_CX when * in EL2. Otherwise, 0. * @config: structure holding configuration parameters. - * @save_state: State to be preserved across power loss * @skip_power_up: Indicates if an implementation can skip powering up * the trace unit. * @paused: Indicates if the trace unit is paused. @@ -1034,7 +978,6 @@ struct etmv4_drvdata { bool lpoverride; u64 trfcr; struct etmv4_config config; - struct etmv4_save_state *save_state; bool skip_power_up; bool paused; DECLARE_BITMAP(arch_features, ETM4_IMPDEF_FEATURE_MAX);