[PATCH v4 0/2] cacheinfo support to read no. of L2 cache ways enabled

[PATCH v4 0/2] cacheinfo support to read no. of L2 cache ways enabled

[Yash Shah]

The patchset includes 2 patches. Patch 1 implements cache_get_priv_group
which make use of a generic ops structure to return a private attribute
group for custom cacheinfo. Patch 2 implements a private attribute named
"number_of_ways_enabled" in the cacheinfo framework. Reading this
attribute returns the number of L2 cache ways enabled at runtime,

This patchset is based on Linux v5.5-rc6 and tested on HiFive Unleashed
board.

v4 vs v3:
- Rename "sifive_l2_largest_wayenabled" to "l2_largest_wayenabled" and
  make it a static function

v3 vs v2:
- As per Anup Patel's suggestion[0], implement a new approach which uses
  generic ops structure. Hence addition of patch 1 to this series and
  corresponding changes to patch 2.
- Dropped "riscv: dts: Add DT support for SiFive L2 cache controller"
  patch since it is already merged
- Rebased on Linux v5.5-rc6

Changes in v2:
- Rebase the series on v5.5-rc3
- Remove the reserved-memory node from DT

[0]: https://lore.kernel.org/linux-riscv/CAAhSdy0CXde5s_ya=4YvmA4UQ5f5gLU-Z_FaOr8LPni+s_615Q@mail.gmail.com/

Yash Shah (2):
  riscv: cacheinfo: Implement cache_get_priv_group with a generic ops
    structure
  riscv: Add support to determine no. of L2 cache way enabled

 arch/riscv/include/asm/cacheinfo.h   | 15 ++++++++++++++
 arch/riscv/kernel/cacheinfo.c        | 17 ++++++++++++++++
 drivers/soc/sifive/sifive_l2_cache.c | 38 ++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 arch/riscv/include/asm/cacheinfo.h

-- 
2.7.4

[PATCH v4 0/2] cacheinfo support to read no. of L2 cache ways enabled

[Yash Shah]

The patchset includes 2 patches. Patch 1 implements cache_get_priv_group
which make use of a generic ops structure to return a private attribute
group for custom cacheinfo. Patch 2 implements a private attribute named
"number_of_ways_enabled" in the cacheinfo framework. Reading this
attribute returns the number of L2 cache ways enabled at runtime,

This patchset is based on Linux v5.5-rc6 and tested on HiFive Unleashed
board.

v4 vs v3:
- Rename "sifive_l2_largest_wayenabled" to "l2_largest_wayenabled" and
  make it a static function

v3 vs v2:
- As per Anup Patel's suggestion[0], implement a new approach which uses
  generic ops structure. Hence addition of patch 1 to this series and
  corresponding changes to patch 2.
- Dropped "riscv: dts: Add DT support for SiFive L2 cache controller"
  patch since it is already merged
- Rebased on Linux v5.5-rc6

Changes in v2:
- Rebase the series on v5.5-rc3
- Remove the reserved-memory node from DT

[0]: https://lore.kernel.org/linux-riscv/CAAhSdy0CXde5s_ya=4YvmA4UQ5f5gLU-Z_FaOr8LPni+s_615Q@mail.gmail.com/

Yash Shah (2):
  riscv: cacheinfo: Implement cache_get_priv_group with a generic ops
    structure
  riscv: Add support to determine no. of L2 cache way enabled

 arch/riscv/include/asm/cacheinfo.h   | 15 ++++++++++++++
 arch/riscv/kernel/cacheinfo.c        | 17 ++++++++++++++++
 drivers/soc/sifive/sifive_l2_cache.c | 38 ++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 arch/riscv/include/asm/cacheinfo.h

-- 
2.7.4

[PATCH v4 1/2] riscv: cacheinfo: Implement cache_get_priv_group with a generic ops structure

[Yash Shah]

Implement cache_get_priv_group() that will make use of a generic ops
structure to return a private attribute group for custom cache info.

Using riscv_set_cacheinfo_ops() users can hook their own custom function
to return the private attribute group for cacheinfo. In future we can
add more ops to this generic ops structure for SOC specific cacheinfo.

Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/include/asm/cacheinfo.h | 15 +++++++++++++++
 arch/riscv/kernel/cacheinfo.c      | 17 +++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 arch/riscv/include/asm/cacheinfo.h

diff --git a/arch/riscv/include/asm/cacheinfo.h b/arch/riscv/include/asm/cacheinfo.h
new file mode 100644
index 0000000..5d9662e
--- /dev/null
+++ b/arch/riscv/include/asm/cacheinfo.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_RISCV_CACHEINFO_H
+#define _ASM_RISCV_CACHEINFO_H
+
+#include <linux/cacheinfo.h>
+
+struct riscv_cacheinfo_ops {
+	const struct attribute_group * (*get_priv_group)(struct cacheinfo
+							*this_leaf);
+};
+
+void riscv_set_cacheinfo_ops(struct riscv_cacheinfo_ops *ops);
+
+#endif /* _ASM_RISCV_CACHEINFO_H */
diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
index 4c90c07..bd0f122 100644
--- a/arch/riscv/kernel/cacheinfo.c
+++ b/arch/riscv/kernel/cacheinfo.c
@@ -7,6 +7,23 @@
 #include <linux/cpu.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <asm/cacheinfo.h>
+
+static struct riscv_cacheinfo_ops *rv_cache_ops;
+
+void riscv_set_cacheinfo_ops(struct riscv_cacheinfo_ops *ops)
+{
+	rv_cache_ops = ops;
+}
+EXPORT_SYMBOL_GPL(riscv_set_cacheinfo_ops);
+
+const struct attribute_group *
+cache_get_priv_group(struct cacheinfo *this_leaf)
+{
+	if (rv_cache_ops && rv_cache_ops->get_priv_group)
+		return rv_cache_ops->get_priv_group(this_leaf);
+	return NULL;
+}
 
 static void ci_leaf_init(struct cacheinfo *this_leaf,
 			 struct device_node *node,
-- 
2.7.4

[PATCH v4 1/2] riscv: cacheinfo: Implement cache_get_priv_group with a generic ops structure

[Yash Shah]

Implement cache_get_priv_group() that will make use of a generic ops
structure to return a private attribute group for custom cache info.

Using riscv_set_cacheinfo_ops() users can hook their own custom function
to return the private attribute group for cacheinfo. In future we can
add more ops to this generic ops structure for SOC specific cacheinfo.

Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/include/asm/cacheinfo.h | 15 +++++++++++++++
 arch/riscv/kernel/cacheinfo.c      | 17 +++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 arch/riscv/include/asm/cacheinfo.h

diff --git a/arch/riscv/include/asm/cacheinfo.h b/arch/riscv/include/asm/cacheinfo.h
new file mode 100644
index 0000000..5d9662e
--- /dev/null
+++ b/arch/riscv/include/asm/cacheinfo.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_RISCV_CACHEINFO_H
+#define _ASM_RISCV_CACHEINFO_H
+
+#include <linux/cacheinfo.h>
+
+struct riscv_cacheinfo_ops {
+	const struct attribute_group * (*get_priv_group)(struct cacheinfo
+							*this_leaf);
+};
+
+void riscv_set_cacheinfo_ops(struct riscv_cacheinfo_ops *ops);
+
+#endif /* _ASM_RISCV_CACHEINFO_H */
diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
index 4c90c07..bd0f122 100644
--- a/arch/riscv/kernel/cacheinfo.c
+++ b/arch/riscv/kernel/cacheinfo.c
@@ -7,6 +7,23 @@
 #include <linux/cpu.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <asm/cacheinfo.h>
+
+static struct riscv_cacheinfo_ops *rv_cache_ops;
+
+void riscv_set_cacheinfo_ops(struct riscv_cacheinfo_ops *ops)
+{
+	rv_cache_ops = ops;
+}
+EXPORT_SYMBOL_GPL(riscv_set_cacheinfo_ops);
+
+const struct attribute_group *
+cache_get_priv_group(struct cacheinfo *this_leaf)
+{
+	if (rv_cache_ops && rv_cache_ops->get_priv_group)
+		return rv_cache_ops->get_priv_group(this_leaf);
+	return NULL;
+}
 
 static void ci_leaf_init(struct cacheinfo *this_leaf,
 			 struct device_node *node,
-- 
2.7.4

[PATCH v4 2/2] riscv: Add support to determine no. of L2 cache way enabled

[Yash Shah]

In order to determine the number of L2 cache ways enabled at runtime,
implement a private attribute ("number_of_ways_enabled"). Reading this
attribute returns the number of enabled L2 cache ways at runtime.

Using riscv_set_cacheinfo_ops() hook a custom function, that returns
this private attribute, to the generic ops structure which is used by
cache_get_priv_group() in cacheinfo framework.

Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 drivers/soc/sifive/sifive_l2_cache.c | 38 ++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/soc/sifive/sifive_l2_cache.c b/drivers/soc/sifive/sifive_l2_cache.c
index a506939..3fb6404 100644
--- a/drivers/soc/sifive/sifive_l2_cache.c
+++ b/drivers/soc/sifive/sifive_l2_cache.c
@@ -9,6 +9,8 @@
 #include <linux/interrupt.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/device.h>
+#include <asm/cacheinfo.h>
 #include <soc/sifive/sifive_l2_cache.h>
 
 #define SIFIVE_L2_DIRECCFIX_LOW 0x100
@@ -31,6 +33,7 @@
 
 static void __iomem *l2_base;
 static int g_irq[SIFIVE_L2_MAX_ECCINTR];
+static struct riscv_cacheinfo_ops l2_cache_ops;
 
 enum {
 	DIR_CORR = 0,
@@ -107,6 +110,38 @@ int unregister_sifive_l2_error_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);
 
+static int l2_largest_wayenabled(void)
+{
+	return readl(l2_base + SIFIVE_L2_WAYENABLE);
+}
+
+static ssize_t number_of_ways_enabled_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	return sprintf(buf, "%u\n", l2_largest_wayenabled());
+}
+
+static DEVICE_ATTR_RO(number_of_ways_enabled);
+
+static struct attribute *priv_attrs[] = {
+	&dev_attr_number_of_ways_enabled.attr,
+	NULL,
+};
+
+static const struct attribute_group priv_attr_group = {
+	.attrs = priv_attrs,
+};
+
+const struct attribute_group *l2_get_priv_group(struct cacheinfo *this_leaf)
+{
+	/* We want to use private group for L2 cache only */
+	if (this_leaf->level == 2)
+		return &priv_attr_group;
+	else
+		return NULL;
+}
+
 static irqreturn_t l2_int_handler(int irq, void *device)
 {
 	unsigned int add_h, add_l;
@@ -170,6 +205,9 @@ static int __init sifive_l2_init(void)
 
 	l2_config_read();
 
+	l2_cache_ops.get_priv_group = l2_get_priv_group;
+	riscv_set_cacheinfo_ops(&l2_cache_ops);
+
 #ifdef CONFIG_DEBUG_FS
 	setup_sifive_debug();
 #endif
-- 
2.7.4

[PATCH v4 2/2] riscv: Add support to determine no. of L2 cache way enabled

[Yash Shah]

In order to determine the number of L2 cache ways enabled at runtime,
implement a private attribute ("number_of_ways_enabled"). Reading this
attribute returns the number of enabled L2 cache ways at runtime.

Using riscv_set_cacheinfo_ops() hook a custom function, that returns
this private attribute, to the generic ops structure which is used by
cache_get_priv_group() in cacheinfo framework.

Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 drivers/soc/sifive/sifive_l2_cache.c | 38 ++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/soc/sifive/sifive_l2_cache.c b/drivers/soc/sifive/sifive_l2_cache.c
index a506939..3fb6404 100644
--- a/drivers/soc/sifive/sifive_l2_cache.c
+++ b/drivers/soc/sifive/sifive_l2_cache.c
@@ -9,6 +9,8 @@
 #include <linux/interrupt.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/device.h>
+#include <asm/cacheinfo.h>
 #include <soc/sifive/sifive_l2_cache.h>
 
 #define SIFIVE_L2_DIRECCFIX_LOW 0x100
@@ -31,6 +33,7 @@
 
 static void __iomem *l2_base;
 static int g_irq[SIFIVE_L2_MAX_ECCINTR];
+static struct riscv_cacheinfo_ops l2_cache_ops;
 
 enum {
 	DIR_CORR = 0,
@@ -107,6 +110,38 @@ int unregister_sifive_l2_error_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);
 
+static int l2_largest_wayenabled(void)
+{
+	return readl(l2_base + SIFIVE_L2_WAYENABLE);
+}
+
+static ssize_t number_of_ways_enabled_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	return sprintf(buf, "%u\n", l2_largest_wayenabled());
+}
+
+static DEVICE_ATTR_RO(number_of_ways_enabled);
+
+static struct attribute *priv_attrs[] = {
+	&dev_attr_number_of_ways_enabled.attr,
+	NULL,
+};
+
+static const struct attribute_group priv_attr_group = {
+	.attrs = priv_attrs,
+};
+
+const struct attribute_group *l2_get_priv_group(struct cacheinfo *this_leaf)
+{
+	/* We want to use private group for L2 cache only */
+	if (this_leaf->level == 2)
+		return &priv_attr_group;
+	else
+		return NULL;
+}
+
 static irqreturn_t l2_int_handler(int irq, void *device)
 {
 	unsigned int add_h, add_l;
@@ -170,6 +205,9 @@ static int __init sifive_l2_init(void)
 
 	l2_config_read();
 
+	l2_cache_ops.get_priv_group = l2_get_priv_group;
+	riscv_set_cacheinfo_ops(&l2_cache_ops);
+
 #ifdef CONFIG_DEBUG_FS
 	setup_sifive_debug();
 #endif
-- 
2.7.4

Re: [PATCH v4 2/2] riscv: Add support to determine no. of L2 cache way enabled

[Palmer Dabbelt]

On Thu, 16 Jan 2020 23:43:38 PST (-0800), yash.shah@sifive.com wrote:
> In order to determine the number of L2 cache ways enabled at runtime,
> implement a private attribute ("number_of_ways_enabled"). Reading this
> attribute returns the number of enabled L2 cache ways at runtime.
>
> Using riscv_set_cacheinfo_ops() hook a custom function, that returns
> this private attribute, to the generic ops structure which is used by
> cache_get_priv_group() in cacheinfo framework.
>
> Signed-off-by: Yash Shah <yash.shah@sifive.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> ---
>  drivers/soc/sifive/sifive_l2_cache.c | 38 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
>
> diff --git a/drivers/soc/sifive/sifive_l2_cache.c b/drivers/soc/sifive/sifive_l2_cache.c
> index a506939..3fb6404 100644
> --- a/drivers/soc/sifive/sifive_l2_cache.c
> +++ b/drivers/soc/sifive/sifive_l2_cache.c
> @@ -9,6 +9,8 @@
>  #include <linux/interrupt.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_address.h>
> +#include <linux/device.h>
> +#include <asm/cacheinfo.h>
>  #include <soc/sifive/sifive_l2_cache.h>
>
>  #define SIFIVE_L2_DIRECCFIX_LOW 0x100
> @@ -31,6 +33,7 @@
>
>  static void __iomem *l2_base;
>  static int g_irq[SIFIVE_L2_MAX_ECCINTR];
> +static struct riscv_cacheinfo_ops l2_cache_ops;
>
>  enum {
>  	DIR_CORR = 0,
> @@ -107,6 +110,38 @@ int unregister_sifive_l2_error_notifier(struct notifier_block *nb)
>  }
>  EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);
>
> +static int l2_largest_wayenabled(void)
> +{
> +	return readl(l2_base + SIFIVE_L2_WAYENABLE);
> +}

WayEnable is 8 bits.

> +
> +static ssize_t number_of_ways_enabled_show(struct device *dev,
> +					   struct device_attribute *attr,
> +					   char *buf)
> +{
> +	return sprintf(buf, "%u\n", l2_largest_wayenabled());
> +}
> +
> +static DEVICE_ATTR_RO(number_of_ways_enabled);
> +
> +static struct attribute *priv_attrs[] = {
> +	&dev_attr_number_of_ways_enabled.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group priv_attr_group = {
> +	.attrs = priv_attrs,
> +};
> +
> +const struct attribute_group *l2_get_priv_group(struct cacheinfo *this_leaf)
> +{
> +	/* We want to use private group for L2 cache only */
> +	if (this_leaf->level == 2)
> +		return &priv_attr_group;
> +	else
> +		return NULL;
> +}
> +
>  static irqreturn_t l2_int_handler(int irq, void *device)
>  {
>  	unsigned int add_h, add_l;
> @@ -170,6 +205,9 @@ static int __init sifive_l2_init(void)
>
>  	l2_config_read();
>
> +	l2_cache_ops.get_priv_group = l2_get_priv_group;
> +	riscv_set_cacheinfo_ops(&l2_cache_ops);
> +
>  #ifdef CONFIG_DEBUG_FS
>  	setup_sifive_debug();
>  #endif

Re: [PATCH v4 2/2] riscv: Add support to determine no. of L2 cache way enabled

[Palmer Dabbelt]

On Thu, 16 Jan 2020 23:43:38 PST (-0800), yash.shah@sifive.com wrote:
> In order to determine the number of L2 cache ways enabled at runtime,
> implement a private attribute ("number_of_ways_enabled"). Reading this
> attribute returns the number of enabled L2 cache ways at runtime.
>
> Using riscv_set_cacheinfo_ops() hook a custom function, that returns
> this private attribute, to the generic ops structure which is used by
> cache_get_priv_group() in cacheinfo framework.
>
> Signed-off-by: Yash Shah <yash.shah@sifive.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> ---
>  drivers/soc/sifive/sifive_l2_cache.c | 38 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
>
> diff --git a/drivers/soc/sifive/sifive_l2_cache.c b/drivers/soc/sifive/sifive_l2_cache.c
> index a506939..3fb6404 100644
> --- a/drivers/soc/sifive/sifive_l2_cache.c
> +++ b/drivers/soc/sifive/sifive_l2_cache.c
> @@ -9,6 +9,8 @@
>  #include <linux/interrupt.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_address.h>
> +#include <linux/device.h>
> +#include <asm/cacheinfo.h>
>  #include <soc/sifive/sifive_l2_cache.h>
>
>  #define SIFIVE_L2_DIRECCFIX_LOW 0x100
> @@ -31,6 +33,7 @@
>
>  static void __iomem *l2_base;
>  static int g_irq[SIFIVE_L2_MAX_ECCINTR];
> +static struct riscv_cacheinfo_ops l2_cache_ops;
>
>  enum {
>  	DIR_CORR = 0,
> @@ -107,6 +110,38 @@ int unregister_sifive_l2_error_notifier(struct notifier_block *nb)
>  }
>  EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);
>
> +static int l2_largest_wayenabled(void)
> +{
> +	return readl(l2_base + SIFIVE_L2_WAYENABLE);
> +}

WayEnable is 8 bits.

> +
> +static ssize_t number_of_ways_enabled_show(struct device *dev,
> +					   struct device_attribute *attr,
> +					   char *buf)
> +{
> +	return sprintf(buf, "%u\n", l2_largest_wayenabled());
> +}
> +
> +static DEVICE_ATTR_RO(number_of_ways_enabled);
> +
> +static struct attribute *priv_attrs[] = {
> +	&dev_attr_number_of_ways_enabled.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group priv_attr_group = {
> +	.attrs = priv_attrs,
> +};
> +
> +const struct attribute_group *l2_get_priv_group(struct cacheinfo *this_leaf)
> +{
> +	/* We want to use private group for L2 cache only */
> +	if (this_leaf->level == 2)
> +		return &priv_attr_group;
> +	else
> +		return NULL;
> +}
> +
>  static irqreturn_t l2_int_handler(int irq, void *device)
>  {
>  	unsigned int add_h, add_l;
> @@ -170,6 +205,9 @@ static int __init sifive_l2_init(void)
>
>  	l2_config_read();
>
> +	l2_cache_ops.get_priv_group = l2_get_priv_group;
> +	riscv_set_cacheinfo_ops(&l2_cache_ops);
> +
>  #ifdef CONFIG_DEBUG_FS
>  	setup_sifive_debug();
>  #endif

RE: [PATCH v4 2/2] riscv: Add support to determine no. of L2 cache way enabled

[Yash Shah]

> -----Original Message-----
> From: Palmer Dabbelt <palmerdabbelt@google.com>
> Sent: 07 February 2020 23:54
> To: Yash Shah <yash.shah@sifive.com>
> Cc: Paul Walmsley ( Sifive) <paul.walmsley@sifive.com>;
> aou@eecs.berkeley.edu; allison@lohutok.net; alexios.zavras@intel.com;
> Greg KH <gregkh@linuxfoundation.org>; tglx@linutronix.de; bp@suse.de;
> anup@brainfault.org; linux-riscv@lists.infradead.org; linux-
> kernel@vger.kernel.org; Sachin Ghadi <sachin.ghadi@sifive.com>; Yash Shah
> <yash.shah@sifive.com>
> Subject: Re: [PATCH v4 2/2] riscv: Add support to determine no. of L2 cache
> way enabled
> 
> On Thu, 16 Jan 2020 23:43:38 PST (-0800), yash.shah@sifive.com wrote:
> > In order to determine the number of L2 cache ways enabled at runtime,
> > implement a private attribute ("number_of_ways_enabled"). Reading this
> > attribute returns the number of enabled L2 cache ways at runtime.
> >
> > Using riscv_set_cacheinfo_ops() hook a custom function, that returns
> > this private attribute, to the generic ops structure which is used by
> > cache_get_priv_group() in cacheinfo framework.
> >
> > Signed-off-by: Yash Shah <yash.shah@sifive.com>
> > Reviewed-by: Anup Patel <anup@brainfault.org>
> > ---
> >  drivers/soc/sifive/sifive_l2_cache.c | 38
> > ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 38 insertions(+)
> >
> > diff --git a/drivers/soc/sifive/sifive_l2_cache.c
> > b/drivers/soc/sifive/sifive_l2_cache.c
> > index a506939..3fb6404 100644
> > --- a/drivers/soc/sifive/sifive_l2_cache.c
> > +++ b/drivers/soc/sifive/sifive_l2_cache.c
> > @@ -9,6 +9,8 @@
> >  #include <linux/interrupt.h>
> >  #include <linux/of_irq.h>
> >  #include <linux/of_address.h>
> > +#include <linux/device.h>
> > +#include <asm/cacheinfo.h>
> >  #include <soc/sifive/sifive_l2_cache.h>
> >
> >  #define SIFIVE_L2_DIRECCFIX_LOW 0x100 @@ -31,6 +33,7 @@
> >
> >  static void __iomem *l2_base;
> >  static int g_irq[SIFIVE_L2_MAX_ECCINTR];
> > +static struct riscv_cacheinfo_ops l2_cache_ops;
> >
> >  enum {
> >  	DIR_CORR = 0,
> > @@ -107,6 +110,38 @@ int unregister_sifive_l2_error_notifier(struct
> > notifier_block *nb)  }
> > EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);
> >
> > +static int l2_largest_wayenabled(void) {
> > +	return readl(l2_base + SIFIVE_L2_WAYENABLE); }
> 
> WayEnable is 8 bits.

Ok, will mask out and return the last 8 bits only

Thanks for your comment.

- Yash

RE: [PATCH v4 2/2] riscv: Add support to determine no. of L2 cache way enabled

[Yash Shah]

> -----Original Message-----
> From: Palmer Dabbelt <palmerdabbelt@google.com>
> Sent: 07 February 2020 23:54
> To: Yash Shah <yash.shah@sifive.com>
> Cc: Paul Walmsley ( Sifive) <paul.walmsley@sifive.com>;
> aou@eecs.berkeley.edu; allison@lohutok.net; alexios.zavras@intel.com;
> Greg KH <gregkh@linuxfoundation.org>; tglx@linutronix.de; bp@suse.de;
> anup@brainfault.org; linux-riscv@lists.infradead.org; linux-
> kernel@vger.kernel.org; Sachin Ghadi <sachin.ghadi@sifive.com>; Yash Shah
> <yash.shah@sifive.com>
> Subject: Re: [PATCH v4 2/2] riscv: Add support to determine no. of L2 cache
> way enabled
> 
> On Thu, 16 Jan 2020 23:43:38 PST (-0800), yash.shah@sifive.com wrote:
> > In order to determine the number of L2 cache ways enabled at runtime,
> > implement a private attribute ("number_of_ways_enabled"). Reading this
> > attribute returns the number of enabled L2 cache ways at runtime.
> >
> > Using riscv_set_cacheinfo_ops() hook a custom function, that returns
> > this private attribute, to the generic ops structure which is used by
> > cache_get_priv_group() in cacheinfo framework.
> >
> > Signed-off-by: Yash Shah <yash.shah@sifive.com>
> > Reviewed-by: Anup Patel <anup@brainfault.org>
> > ---
> >  drivers/soc/sifive/sifive_l2_cache.c | 38
> > ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 38 insertions(+)
> >
> > diff --git a/drivers/soc/sifive/sifive_l2_cache.c
> > b/drivers/soc/sifive/sifive_l2_cache.c
> > index a506939..3fb6404 100644
> > --- a/drivers/soc/sifive/sifive_l2_cache.c
> > +++ b/drivers/soc/sifive/sifive_l2_cache.c
> > @@ -9,6 +9,8 @@
> >  #include <linux/interrupt.h>
> >  #include <linux/of_irq.h>
> >  #include <linux/of_address.h>
> > +#include <linux/device.h>
> > +#include <asm/cacheinfo.h>
> >  #include <soc/sifive/sifive_l2_cache.h>
> >
> >  #define SIFIVE_L2_DIRECCFIX_LOW 0x100 @@ -31,6 +33,7 @@
> >
> >  static void __iomem *l2_base;
> >  static int g_irq[SIFIVE_L2_MAX_ECCINTR];
> > +static struct riscv_cacheinfo_ops l2_cache_ops;
> >
> >  enum {
> >  	DIR_CORR = 0,
> > @@ -107,6 +110,38 @@ int unregister_sifive_l2_error_notifier(struct
> > notifier_block *nb)  }
> > EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);
> >
> > +static int l2_largest_wayenabled(void) {
> > +	return readl(l2_base + SIFIVE_L2_WAYENABLE); }
> 
> WayEnable is 8 bits.

Ok, will mask out and return the last 8 bits only

Thanks for your comment.

- Yash