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cpufreq: exynos: use relaxed IO accesors

PATCH New Ben Dooks 4 participants 7 messages Jun 22, 2016

Subsystems (2)
Arm Samsung Exynos CPU frequency scaling framework
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Ben Dooks

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#0 lore raw

PATCH 1/2 cpufreq: exynos: use relaxed IO accesors

The use of __raw IO accesors is not endian safe and should be used sparingly. The relaxed variants should be as lightweight and also are endian safe.

Signed-off-by Ben Dooks <[email protected]>

---
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: linux-pm at vger.kernel.org
Cc: linux-samsung-soc at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org

---
 drivers/cpufreq/exynos5440-cpufreq.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)
drivers/cpufreq/exynos5440-cpufreq.c +14 -14
index c0f3373..7a5707f 100644
@@ -155,7 +155,7 @@ static int init_div_table(void)
 		tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
 			| ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
 
-		__raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 *
+		writel_relaxed(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 *
 						(pos - freq_tbl));
 	}
 

@@ -169,17 +169,17 @@ static void exynos_enable_dvfs(unsigned int cur_frequency)
 	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
 	struct cpufreq_frequency_table *pos;
 	/* Disable DVFS */
-	__raw_writel(0,	dvfs_info->base + XMU_DVFS_CTRL);
+	writel_relaxed(0,	dvfs_info->base + XMU_DVFS_CTRL);
 
 	/* Enable PSTATE Change Event */
-	tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
+	tmp = readl_relaxed(dvfs_info->base + XMU_PMUEVTEN);
 	tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
-	 __raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
+	 writel_relaxed(tmp, dvfs_info->base + XMU_PMUEVTEN);
 
 	/* Enable PSTATE Change IRQ */
-	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
+	tmp = readl_relaxed(dvfs_info->base + XMU_PMUIRQEN);
 	tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
-	 __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
+	 writel_relaxed(tmp, dvfs_info->base + XMU_PMUIRQEN);
 
 	/* Set initial performance index */
 	cpufreq_for_each_entry(pos, freq_table)

@@ -197,14 +197,14 @@ static void exynos_enable_dvfs(unsigned int cur_frequency)
 						cur_frequency);
 
 	for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
-		tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
+		tmp = readl_relaxed(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
 		tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
 		tmp |= ((pos - freq_table) << C0_3_PSTATE_NEW_SHIFT);
-		__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
+		writel_relaxed(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
 	}
 
 	/* Enable DVFS */
-	__raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
+	writel_relaxed(1 << XMU_DVFS_CTRL_EN_SHIFT,
 				dvfs_info->base + XMU_DVFS_CTRL);
 }
 

@@ -223,11 +223,11 @@ static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
 
 	/* Set the target frequency in all C0_3_PSTATE register */
 	for_each_cpu(i, policy->cpus) {
-		tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
+		tmp = readl_relaxed(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
 		tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
 		tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
 
-		__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
+		writel_relaxed(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
 	}
 	mutex_unlock(&cpufreq_lock);
 	return 0;

@@ -246,7 +246,7 @@ static void exynos_cpufreq_work(struct work_struct *work)
 	mutex_lock(&cpufreq_lock);
 	freqs.old = policy->cur;
 
-	cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
+	cur_pstate = readl_relaxed(dvfs_info->base + XMU_P_STATUS);
 	if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
 		index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
 	else

@@ -270,9 +270,9 @@ static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
 {
 	unsigned int tmp;
 
-	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
+	tmp = readl_relaxed(dvfs_info->base + XMU_PMUIRQ);
 	if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
-		__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
+		writel_relaxed(tmp, dvfs_info->base + XMU_PMUIRQ);
 		disable_irq_nosync(irq);
 		schedule_work(&dvfs_info->irq_work);
 	}
Signature · 1 line
2.8.1
maintainer
#1 lore raw

PATCH 1/2 cpufreq: exynos: use relaxed IO accesors

Quoted 3 lines · Ben Dooks

The use of __raw IO accesors is not endian safe and should be used sparingly. The relaxed variants should be as lightweight and also are endian safe.

I am not sure if exynos's code is required to be endian safe at all or not, but this change wouldn't harm as well.

Acked-by Viresh Kumar <[email protected]>
Signature · 1 line
viresh
author
#2 lore raw

PATCH 1/2 cpufreq: exynos: use relaxed IO accesors

Quoted 9 lines · Viresh Kumar
Quoted 3 lines · Ben Dooks

The use of __raw IO accesors is not endian safe and should be used sparingly. The relaxed variants should be as lightweight and also are endian safe.

I am not sure if exynos's code is required to be endian safe at all or not, but this change wouldn't harm as well.

Acked-by Viresh Kumar <[email protected]>

It is better for any of the ARMv7 and later to do this. We've been fixing some of the exynos and other code to be endian safe.

Signature · 2 lines
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius
#3 lore raw

PATCH 1/2 cpufreq: exynos: use relaxed IO accesors

In reply to Ben Dooks
Quoted 6 lines · CEST Ben Dooks

The use of __raw IO accesors is not endian safe and should be used sparingly. The relaxed variants should be as lightweight and also are endian safe.

Signed-off-by Ben Dooks <[email protected]>

Why not use the normal readl/writel() here instead of the relaxed version?

Either one should work here, but in general I'd recommend using the non-relaxed version unless code is particularly performance sensitive.

The main argument for that is to not let people get used to using _relaxed() all the time because it causes some very hard to debug problems in the cases where you actually need the barriers.

Arnd

#4 lore raw

PATCH 1/2 cpufreq: exynos: use relaxed IO accesors

Quoted 8 lines · Arnd Bergmann
Quoted 6 lines · CEST Ben Dooks

The use of __raw IO accesors is not endian safe and should be used sparingly. The relaxed variants should be as lightweight and also are endian safe.

Signed-off-by Ben Dooks <[email protected]>
Quoted 8 lines

Why not use the normal readl/writel() here instead of the relaxed version?

Either one should work here, but in general I'd recommend using the non-relaxed version unless code is particularly performance sensitive.

The main argument for that is to not let people get used to using _relaxed() all the time because it causes some very hard to debug problems in the cases where you actually need the barriers.

I think that would be actually different patch, not endian related. The concurrent operations here are excluded by mutexes so this looks safe.

Viresh,
I saw your ack. Do you prefer me to take the set through samsung-soc?

Best regards,
Krzysztof

maintainer
#5 lore raw

PATCH 1/2 cpufreq: exynos: use relaxed IO accesors

Quoted 18 lines · Krzysztof Kozlowski
Quoted 8 lines · Arnd Bergmann
Quoted 6 lines · CEST Ben Dooks

The use of __raw IO accesors is not endian safe and should be used sparingly. The relaxed variants should be as lightweight and also are endian safe.

Signed-off-by Ben Dooks <[email protected]>
Quoted 8 lines

Why not use the normal readl/writel() here instead of the relaxed version?

Either one should work here, but in general I'd recommend using the non-relaxed version unless code is particularly performance sensitive.

The main argument for that is to not let people get used to using _relaxed() all the time because it causes some very hard to debug problems in the cases where you actually need the barriers.

Quoted 6 lines

I think that would be actually different patch, not endian related. The concurrent operations here are excluded by mutexes so this looks safe.

Viresh,
I saw your ack. Do you prefer me to take the set through samsung-soc?

Sure.

Signature · 1 line
viresh
#6 lore raw

PATCH 1/2 cpufreq: exynos: use relaxed IO accesors

In reply to Ben Dooks
Quoted 29 lines · Ben Dooks

The use of __raw IO accesors is not endian safe and should be used sparingly. The relaxed variants should be as lightweight and also are endian safe.

Signed-off-by Ben Dooks <[email protected]>

---
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: linux-pm at vger.kernel.org
Cc: linux-samsung-soc at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org

---
 drivers/cpufreq/exynos5440-cpufreq.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)
drivers/cpufreq/exynos5440-cpufreq.c +1 -1
index c0f3373..7a5707f 100644
@@ -155,7 +155,7 @@ static int init_div_table(void)
                tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
                        | ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
 
-               __raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 *
+               writel_relaxed(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 *
                                                (pos - freq_tbl));
        }

drivers/cpufreq/exynos5440-cpufreq.c static void exynos_enable_dvfs(unsigned int cur_frequency) · line 172

Quoted 5 lines
drivers/cpufreq/exynos5440-cpufreq.c +1 -1
@@ -169,17 +169,17 @@ static void exynos_enable_dvfs(unsigned int cur_frequency)
        struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
        struct cpufreq_frequency_table *pos;
        /* Disable DVFS */
-       __raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);
+       writel_relaxed(0,       dvfs_info->base + XMU_DVFS_CTRL);

Please fix the whitespace.

Rest looks good but this patch appeared twice. I suspect they are the same?

Best regards,
Krzysztof