4 files changed, 16 insertions, 11 deletions

diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
index 202c83f677b2..96648c176f37 100644
--- a/arch/riscv/errata/thead/errata.c
+++ b/arch/riscv/errata/thead/errata.c
@@ -37,6 +37,7 @@ static bool errata_probe_cmo(unsigned int stage,
 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
 		return false;
 
+	riscv_cbom_block_size = L1_CACHE_BYTES;
 	riscv_noncoherent_supported();
 	return true;
 #else
diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h
index a60acaecfeda..a89c005b4bbf 100644
--- a/arch/riscv/include/asm/cacheflush.h
+++ b/arch/riscv/include/asm/cacheflush.h
@@ -43,6 +43,7 @@ void flush_icache_mm(struct mm_struct *mm, bool local);
 #endif /* CONFIG_SMP */
 
 #ifdef CONFIG_RISCV_ISA_ZICBOM
+extern unsigned int riscv_cbom_block_size;
 void riscv_init_cbom_blocksize(void);
 #else
 static inline void riscv_init_cbom_blocksize(void) { }
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 95ef6e2bf45c..2dfc463b86bb 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -296,8 +296,8 @@ void __init setup_arch(char **cmdline_p)
 	setup_smp();
 #endif
 
-	riscv_fill_hwcap();
 	riscv_init_cbom_blocksize();
+	riscv_fill_hwcap();
 	apply_boot_alternatives();
 }
 
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index cd2225304c82..e3f9bdf47c5f 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -12,7 +12,7 @@
 #include <linux/of_device.h>
 #include <asm/cacheflush.h>
 
-static unsigned int riscv_cbom_block_size = L1_CACHE_BYTES;
+unsigned int riscv_cbom_block_size;
 static bool noncoherent_supported;
 
 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
@@ -79,38 +79,41 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 void riscv_init_cbom_blocksize(void)
 {
 	struct device_node *node;
+	unsigned long cbom_hartid;
+	u32 val, probed_block_size;
 	int ret;
-	u32 val;
 
+	probed_block_size = 0;
 	for_each_of_cpu_node(node) {
 		unsigned long hartid;
-		int cbom_hartid;
 
 		ret = riscv_of_processor_hartid(node, &hartid);
 		if (ret)
 			continue;
 
-		if (hartid < 0)
-			continue;
-
 		/* set block-size for cbom extension if available */
 		ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
 		if (ret)
 			continue;
 
-		if (!riscv_cbom_block_size) {
-			riscv_cbom_block_size = val;
+		if (!probed_block_size) {
+			probed_block_size = val;
 			cbom_hartid = hartid;
 		} else {
-			if (riscv_cbom_block_size != val)
-				pr_warn("cbom-block-size mismatched between harts %d and %lu\n",
+			if (probed_block_size != val)
+				pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
 					cbom_hartid, hartid);
 		}
 	}
+
+	if (probed_block_size)
+		riscv_cbom_block_size = probed_block_size;
 }
 #endif
 
 void riscv_noncoherent_supported(void)
 {
+	WARN(!riscv_cbom_block_size,
+	     "Non-coherent DMA support enabled without a block size\n");
 	noncoherent_supported = true;
 }