diff mbox series

[RFC,v1,08/21] RISC-V: ACPI: RHCT: Add function to get CBO block sizes

Message ID 20230803175916.3174453-9-sunilvl@ventanamicro.com
State New
Headers
Series RISC-V: ACPI: Add external interrupt controller support |

Commit Message

Sunil V L Aug. 3, 2023, 5:59 p.m. UTC 
  CBO related block size in ACPI is provided by RHCT. Add
support to read the CMO node in RHCT to get this information.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 arch/riscv/include/asm/acpi.h |  9 ++++++
 drivers/acpi/riscv/rhct.c     | 61 +++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

Comments

Andy Shevchenko Aug. 4, 2023, 6 a.m. UTC | #1 
On Thu, Aug 03, 2023 at 11:29:03PM +0530, Sunil V L wrote:
> CBO related block size in ACPI is provided by RHCT. Add
> support to read the CMO node in RHCT to get this information.

...

> +	if (!table) {

Why not positive conditional?

> +		rhct = (struct acpi_table_rhct *)acpi_get_rhct();
> +		if (!rhct)
> +			return -ENOENT;
> +	} else {
> +		rhct = (struct acpi_table_rhct *)table;
> +	}

...

> +	end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);

> +

Blank line here is not needed.

> +	for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
> +	     node < end;
> +	     node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {

> +			for (int i = 0; i < hart_info->num_offsets; i++) {
> +				ref_node = ACPI_ADD_PTR(struct acpi_rhct_node_header,
> +							rhct, hart_info_node_offset[i]);
> +				if (ref_node->type == ACPI_RHCT_NODE_TYPE_CMO) {
> +					cmo_node = ACPI_ADD_PTR(struct acpi_rhct_cmo_node,
> +								ref_node, size_hdr);
> +					if (cbom_size)
> +						*cbom_size = 1 << cmo_node->cbom_size;
> +
> +					if (cboz_size)
> +						*cboz_size = 1 << cmo_node->cboz_size;
> +
> +					if (cbop_size)
> +						*cbop_size = 1 << cmo_node->cbop_size;

BIT() in all three cases?

But how you guarantee it will not overflow? I mean who prevents cboX_size to be
bigger than 30 (note also that 31 in your case is Undefined Behaviour in
accordance with the C standard).

> +					return 0;
> +				}
> +			}

> +	}
Sunil V L Aug. 4, 2023, 9:33 a.m. UTC | #2 
On Fri, Aug 04, 2023 at 09:00:45AM +0300, Andy Shevchenko wrote:
> On Thu, Aug 03, 2023 at 11:29:03PM +0530, Sunil V L wrote:
> > CBO related block size in ACPI is provided by RHCT. Add
> > support to read the CMO node in RHCT to get this information.
> 
> ...
> 
> > +	if (!table) {
> 
> Why not positive conditional?
> 
Sure.

> > +		rhct = (struct acpi_table_rhct *)acpi_get_rhct();
> > +		if (!rhct)
> > +			return -ENOENT;
> > +	} else {
> > +		rhct = (struct acpi_table_rhct *)table;
> > +	}
> 
> ...
> 
> > +	end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);
> 
> > +
> 
> Blank line here is not needed.
> 
Okay.

> > +	for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
> > +	     node < end;
> > +	     node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {
> 
> > +			for (int i = 0; i < hart_info->num_offsets; i++) {
> > +				ref_node = ACPI_ADD_PTR(struct acpi_rhct_node_header,
> > +							rhct, hart_info_node_offset[i]);
> > +				if (ref_node->type == ACPI_RHCT_NODE_TYPE_CMO) {
> > +					cmo_node = ACPI_ADD_PTR(struct acpi_rhct_cmo_node,
> > +								ref_node, size_hdr);
> > +					if (cbom_size)
> > +						*cbom_size = 1 << cmo_node->cbom_size;
> > +
> > +					if (cboz_size)
> > +						*cboz_size = 1 << cmo_node->cboz_size;
> > +
> > +					if (cbop_size)
> > +						*cbop_size = 1 << cmo_node->cbop_size;
> 
> BIT() in all three cases?
>
Sure.
 
> But how you guarantee it will not overflow? I mean who prevents cboX_size to be
> bigger than 30 (note also that 31 in your case is Undefined Behaviour in
> accordance with the C standard).
> 
Good catch!. Let me add a check that the value is not more than 30.

Thanks!
Sunil
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
index d5604d2073bc..0c4e8b35103e 100644
--- a/arch/riscv/include/asm/acpi.h
+++ b/arch/riscv/include/asm/acpi.h
@@ -66,6 +66,8 @@  int acpi_get_riscv_isa(struct acpi_table_header *table,
 		       unsigned int cpu, const char **isa);
 
 static inline int acpi_numa_get_nid(unsigned int cpu) { return NUMA_NO_NODE; }
+int acpi_get_cbo_block_size(struct acpi_table_header *table, unsigned int cpu, u32 *cbom_size,
+			    u32 *cboz_size, u32 *cbop_size);
 #else
 static inline void acpi_init_rintc_map(void) { }
 static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
@@ -79,6 +81,13 @@  static inline int acpi_get_riscv_isa(struct acpi_table_header *table,
 	return -EINVAL;
 }
 
+static inline int acpi_get_cbo_block_size(struct acpi_table_header *table,
+					  unsigned int cpu, u32 *cbom_size,
+					  u32 *cboz_size, u32 *cbop_size)
+{
+	return -EINVAL;
+}
+
 #endif /* CONFIG_ACPI */
 
 #endif /*_ASM_ACPI_H*/
diff --git a/drivers/acpi/riscv/rhct.c b/drivers/acpi/riscv/rhct.c
index b280b3e9c7d9..07309525f277 100644
--- a/drivers/acpi/riscv/rhct.c
+++ b/drivers/acpi/riscv/rhct.c
@@ -81,3 +81,64 @@  int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const
 
 	return -1;
 }
+
+/*
+ * During early boot, the caller should call acpi_get_table() and pass its pointer to
+ * these functions(and free up later). At run time, since this table can be used
+ * multiple times, pass NULL so that the table remains in memory
+ */
+int acpi_get_cbo_block_size(struct acpi_table_header *table, unsigned int cpu,
+			    u32 *cbom_size, u32 *cboz_size, u32 *cbop_size)
+{
+	struct acpi_rhct_node_header *node, *ref_node, *end;
+	u32 size_hdr = sizeof(struct acpi_rhct_node_header);
+	u32 size_hartinfo = sizeof(struct acpi_rhct_hart_info);
+	struct acpi_rhct_hart_info *hart_info;
+	struct acpi_rhct_cmo_node *cmo_node;
+	struct acpi_table_rhct *rhct;
+	u32 *hart_info_node_offset;
+	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+
+	BUG_ON(acpi_disabled);
+
+	if (!table) {
+		rhct = (struct acpi_table_rhct *)acpi_get_rhct();
+		if (!rhct)
+			return -ENOENT;
+	} else {
+		rhct = (struct acpi_table_rhct *)table;
+	}
+
+	end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);
+
+	for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
+	     node < end;
+	     node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {
+		if (node->type == ACPI_RHCT_NODE_TYPE_HART_INFO) {
+			hart_info = ACPI_ADD_PTR(struct acpi_rhct_hart_info, node, size_hdr);
+			hart_info_node_offset = ACPI_ADD_PTR(u32, hart_info, size_hartinfo);
+			if (acpi_cpu_id != hart_info->uid)
+				continue;
+
+			for (int i = 0; i < hart_info->num_offsets; i++) {
+				ref_node = ACPI_ADD_PTR(struct acpi_rhct_node_header,
+							rhct, hart_info_node_offset[i]);
+				if (ref_node->type == ACPI_RHCT_NODE_TYPE_CMO) {
+					cmo_node = ACPI_ADD_PTR(struct acpi_rhct_cmo_node,
+								ref_node, size_hdr);
+					if (cbom_size)
+						*cbom_size = 1 << cmo_node->cbom_size;
+
+					if (cboz_size)
+						*cboz_size = 1 << cmo_node->cboz_size;
+
+					if (cbop_size)
+						*cbop_size = 1 << cmo_node->cbop_size;
+					return 0;
+				}
+			}
+		}
+	}
+
+	return -ENOENT;
+}