From 7aa0557fae5ce26dddc877869c7ad934e71f30db Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 29 Apr 2014 00:24:09 +0530 Subject: [PATCH 1/5] cpufreq: longhaul: Fix double invocation of cpufreq_freq_transition_begin/end During frequency transitions, the cpufreq core takes the responsibility of invoking cpufreq_freq_transition_begin() and cpufreq_freq_transition_end() for those cpufreq drivers that define the ->target_index callback but don't set the ASYNC_NOTIFICATION flag. The longhaul cpufreq driver falls under this category, but this driver was invoking the _begin() and _end() APIs itself around frequency transitions, which led to double invocation of the _begin() API. The _begin API makes contending callers wait until the previous invocation is complete. Hence, the longhaul driver ended up waiting on itself, leading to system hangs during boot. Fix this by removing the calls to the _begin() and _end() APIs from the longhaul driver, since they rightly belong to the cpufreq core. (Note that during module_exit(), the longhaul driver sets the frequency without any help from the cpufreq core. So add explicit calls to the _begin() and _end() APIs around that frequency transition alone, to take care of that special case.) Fixes: 12478cf0c55e (cpufreq: Make sure frequency transitions are serialized) Reported-and-tested-by: Meelis Roos Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/longhaul.c | 36 ++++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c index d00e5d1abd25..5c4369b5d834 100644 --- a/drivers/cpufreq/longhaul.c +++ b/drivers/cpufreq/longhaul.c @@ -242,7 +242,7 @@ static void do_powersaver(int cx_address, unsigned int mults_index, * Sets a new clock ratio. */ -static void longhaul_setstate(struct cpufreq_policy *policy, +static int longhaul_setstate(struct cpufreq_policy *policy, unsigned int table_index) { unsigned int mults_index; @@ -258,10 +258,12 @@ static void longhaul_setstate(struct cpufreq_policy *policy, /* Safety precautions */ mult = mults[mults_index & 0x1f]; if (mult == -1) - return; + return -EINVAL; + speed = calc_speed(mult); if ((speed > highest_speed) || (speed < lowest_speed)) - return; + return -EINVAL; + /* Voltage transition before frequency transition? */ if (can_scale_voltage && longhaul_index < table_index) dir = 1; @@ -269,8 +271,6 @@ static void longhaul_setstate(struct cpufreq_policy *policy, freqs.old = calc_speed(longhaul_get_cpu_mult()); freqs.new = speed; - cpufreq_freq_transition_begin(policy, &freqs); - pr_debug("Setting to FSB:%dMHz Mult:%d.%dx (%s)\n", fsb, mult/10, mult%10, print_speed(speed/1000)); retry_loop: @@ -385,12 +385,14 @@ retry_loop: goto retry_loop; } } - /* Report true CPU frequency */ - cpufreq_freq_transition_end(policy, &freqs, 0); - if (!bm_timeout) + if (!bm_timeout) { printk(KERN_INFO PFX "Warning: Timeout while waiting for " "idle PCI bus.\n"); + return -EBUSY; + } + + return 0; } /* @@ -631,9 +633,10 @@ static int longhaul_target(struct cpufreq_policy *policy, unsigned int i; unsigned int dir = 0; u8 vid, current_vid; + int retval = 0; if (!can_scale_voltage) - longhaul_setstate(policy, table_index); + retval = longhaul_setstate(policy, table_index); else { /* On test system voltage transitions exceeding single * step up or down were turning motherboard off. Both @@ -648,7 +651,7 @@ static int longhaul_target(struct cpufreq_policy *policy, while (i != table_index) { vid = (longhaul_table[i].driver_data >> 8) & 0x1f; if (vid != current_vid) { - longhaul_setstate(policy, i); + retval = longhaul_setstate(policy, i); current_vid = vid; msleep(200); } @@ -657,10 +660,11 @@ static int longhaul_target(struct cpufreq_policy *policy, else i--; } - longhaul_setstate(policy, table_index); + retval = longhaul_setstate(policy, table_index); } + longhaul_index = table_index; - return 0; + return retval; } @@ -968,7 +972,15 @@ static void __exit longhaul_exit(void) for (i = 0; i < numscales; i++) { if (mults[i] == maxmult) { + struct cpufreq_freqs freqs; + + freqs.old = policy->cur; + freqs.new = longhaul_table[i].frequency; + freqs.flags = 0; + + cpufreq_freq_transition_begin(policy, &freqs); longhaul_setstate(policy, i); + cpufreq_freq_transition_end(policy, &freqs, 0); break; } } From 237ede16ba5bcd4d6c612ea280518c48ca31986c Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 29 Apr 2014 00:24:27 +0530 Subject: [PATCH 2/5] cpufreq: powernow-k6: Fix incorrect comparison with max_multipler The value of 'max_multiplier' is meant to be used for comparison with clock_ratio[index].driver_data, not the index itself! Fix the code in powernow_k6_cpu_exit() that has this bug. Also, while at it, make the for-loop condition look for CPUFREQ_TABLE_END, instead of hard-coding the loop count to 8. Reported-by: Viresh Kumar Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/powernow-k6.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c index 49f120e1bc7b..695a68cfdcd4 100644 --- a/drivers/cpufreq/powernow-k6.c +++ b/drivers/cpufreq/powernow-k6.c @@ -227,8 +227,9 @@ have_busfreq: static int powernow_k6_cpu_exit(struct cpufreq_policy *policy) { unsigned int i; - for (i = 0; i < 8; i++) { - if (i == max_multiplier) + + for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) { + if (clock_ratio[i].driver_data == max_multiplier) powernow_k6_target(policy, i); } return 0; From 3221e55b72359c44ed75afbcf707710af5bc2d59 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 29 Apr 2014 00:24:42 +0530 Subject: [PATCH 3/5] cpufreq: powernow-k6: Fix double invocation of cpufreq_freq_transition_begin/end During frequency transitions, the cpufreq core takes the responsibility of invoking cpufreq_freq_transition_begin() and cpufreq_freq_transition_end() for those cpufreq drivers that define the ->target_index callback but don't set the ASYNC_NOTIFICATION flag. The powernow-k6 cpufreq driver falls under this category, but this driver was invoking the _begin() and _end() APIs itself around frequency transitions, which led to double invocation of the _begin() API. The _begin API makes contending callers wait until the previous invocation is complete. Hence, the powernow-k6 driver ended up waiting on itself, leading to system hangs during boot. Fix this by removing the calls to the _begin() and _end() APIs from the powernow-k6 driver, since they rightly belong to the cpufreq core. (Note that during ->exit(), the powernow-k6 driver sets the frequency without any help from the cpufreq core. So add explicit calls to the _begin() and _end() APIs around that frequency transition alone, to take care of that special case. Also, add a missing 'break' statement there.) Fixes: 12478cf0c55e (cpufreq: Make sure frequency transitions are serialized) Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/powernow-k6.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c index 695a68cfdcd4..78904e6ca4a0 100644 --- a/drivers/cpufreq/powernow-k6.c +++ b/drivers/cpufreq/powernow-k6.c @@ -138,22 +138,14 @@ static void powernow_k6_set_cpu_multiplier(unsigned int best_i) static int powernow_k6_target(struct cpufreq_policy *policy, unsigned int best_i) { - struct cpufreq_freqs freqs; if (clock_ratio[best_i].driver_data > max_multiplier) { printk(KERN_ERR PFX "invalid target frequency\n"); return -EINVAL; } - freqs.old = busfreq * powernow_k6_get_cpu_multiplier(); - freqs.new = busfreq * clock_ratio[best_i].driver_data; - - cpufreq_freq_transition_begin(policy, &freqs); - powernow_k6_set_cpu_multiplier(best_i); - cpufreq_freq_transition_end(policy, &freqs, 0); - return 0; } @@ -229,8 +221,18 @@ static int powernow_k6_cpu_exit(struct cpufreq_policy *policy) unsigned int i; for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) { - if (clock_ratio[i].driver_data == max_multiplier) + if (clock_ratio[i].driver_data == max_multiplier) { + struct cpufreq_freqs freqs; + + freqs.old = policy->cur; + freqs.new = clock_ratio[i].frequency; + freqs.flags = 0; + + cpufreq_freq_transition_begin(policy, &freqs); powernow_k6_target(policy, i); + cpufreq_freq_transition_end(policy, &freqs, 0); + break; + } } return 0; } From 8997b185119966c62c6e95e7b010b4060407e358 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 29 Apr 2014 00:24:58 +0530 Subject: [PATCH 4/5] cpufreq: powernow-k7: Fix double invocation of cpufreq_freq_transition_begin/end During frequency transitions, the cpufreq core takes the responsibility of invoking cpufreq_freq_transition_begin() and cpufreq_freq_transition_end() for those cpufreq drivers that define the ->target_index callback but don't set the ASYNC_NOTIFICATION flag. The powernow-k7 cpufreq driver falls under this category, but this driver was invoking the _begin() and _end() APIs itself around frequency transitions, which led to double invocation of the _begin() API. The _begin API makes contending callers wait until the previous invocation is complete. Hence, the powernow-k7 driver ended up waiting on itself, leading to system hangs during boot. Fix this by removing the calls to the _begin() and _end() APIs from the powernow-k7 driver, since they rightly belong to the cpufreq core. Fixes: 12478cf0c55e (cpufreq: Make sure frequency transitions are serialized) Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/powernow-k7.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/cpufreq/powernow-k7.c b/drivers/cpufreq/powernow-k7.c index f911645c3f6d..e61e224475ad 100644 --- a/drivers/cpufreq/powernow-k7.c +++ b/drivers/cpufreq/powernow-k7.c @@ -269,8 +269,6 @@ static int powernow_target(struct cpufreq_policy *policy, unsigned int index) freqs.new = powernow_table[index].frequency; - cpufreq_freq_transition_begin(policy, &freqs); - /* Now do the magic poking into the MSRs. */ if (have_a0 == 1) /* A0 errata 5 */ @@ -290,8 +288,6 @@ static int powernow_target(struct cpufreq_policy *policy, unsigned int index) if (have_a0 == 1) local_irq_enable(); - cpufreq_freq_transition_end(policy, &freqs, 0); - return 0; } From 6712d2931933ada259b82f06c03a855b19937074 Mon Sep 17 00:00:00 2001 From: Tim Gardner Date: Mon, 28 Apr 2014 10:18:18 -0600 Subject: [PATCH 5/5] cpufreq: ppc-corenet-cpufreq: Fix __udivdi3 modpost error bfa709bc823fc32ee8dd5220d1711b46078235d8 (cpufreq: powerpc: add cpufreq transition latency for FSL e500mc SoCs) introduced a modpost error: ERROR: "__udivdi3" [drivers/cpufreq/ppc-corenet-cpufreq.ko] undefined! make[1]: *** [__modpost] Error 1 Fix this by avoiding 64 bit integer division. gcc version 4.8.2 Fixes: bfa709bc823f (cpufreq: powerpc: add cpufreq transition latency for FSL e500mc SoCs) Signed-off-by: Tim Gardner Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/ppc-corenet-cpufreq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c index a1ca3dd04a8e..0af618abebaf 100644 --- a/drivers/cpufreq/ppc-corenet-cpufreq.c +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c @@ -138,6 +138,7 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy) struct cpufreq_frequency_table *table; struct cpu_data *data; unsigned int cpu = policy->cpu; + u64 transition_latency_hz; np = of_get_cpu_node(cpu, NULL); if (!np) @@ -205,8 +206,10 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy) for_each_cpu(i, per_cpu(cpu_mask, cpu)) per_cpu(cpu_data, i) = data; + transition_latency_hz = 12ULL * NSEC_PER_SEC; policy->cpuinfo.transition_latency = - (12ULL * NSEC_PER_SEC) / fsl_get_sys_freq(); + do_div(transition_latency_hz, fsl_get_sys_freq()); + of_node_put(np); return 0;