RISC-V: cacheflush: Initialize CBO variables on ACPI systems

Initialize the CBO variables on ACPI based systems using information in
RHCT.
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20231018124007.1306159-5-sunilvl@ventanamicro.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/mm/cacheflush.c

@@ -3,7 +3,9 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/acpi.h>
 #include <linux/of.h>
+#include <asm/acpi.h>
 #include <asm/cacheflush.h>
 
 #ifdef CONFIG_SMP
@@ -124,7 +126,10 @@ void __init riscv_init_cbo_blocksizes(void)
 	unsigned long cbom_hartid, cboz_hartid;
 	u32 cbom_block_size = 0, cboz_block_size = 0;
 	struct device_node *node;
+	struct acpi_table_header *rhct;
+	acpi_status status;
 
+	if (acpi_disabled) {
 		for_each_of_cpu_node(node) {
 			/* set block-size for cbom and/or cboz extension if available */
 			cbo_get_block_size(node, "riscv,cbom-block-size",
@@ -132,6 +137,14 @@ void __init riscv_init_cbo_blocksizes(void)
 			cbo_get_block_size(node, "riscv,cboz-block-size",
 					   &cboz_block_size, &cboz_hartid);
 		}
+	} else {
+		status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
+		if (ACPI_FAILURE(status))
+			return;
+
+		acpi_get_cbo_block_size(rhct, &cbom_block_size, &cboz_block_size, NULL);
+		acpi_put_table((struct acpi_table_header *)rhct);
+	}
 
 	if (cbom_block_size)
 		riscv_cbom_block_size = cbom_block_size;