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From: "David E. Garcia Porras" <david.garcia@aheadcomputing.com>
To: opensbi@lists.infradead.org
Cc: "David E. Garcia Porras" <david.garcia@aheadcomputing.com>
Subject: [PATCH] lib: utils/regmap: Fix reg_stride calculation in syscon regmap
Date: Fri,  3 Apr 2026 14:29:03 -0600	[thread overview]
Message-ID: <20260403202903.3407945-1-david.garcia@aheadcomputing.com> (raw)

The reg_stride field represents the address stride in bytes between
consecutive registers. The Linux kernel regmap framework validates
register accesses using IS_ALIGNED(reg, map->reg_stride) as an address
alignment check (drivers/base/regmap/regmap.c). The Linux kernel syscon
driver (drivers/mfd/syscon.c) sets reg_stride directly to reg_io_width:

  syscon_config.reg_stride = reg_io_width;

The current OpenSBI code incorrectly multiplies reg_io_width by 8,
converting a byte value to bits. Fix this by using reg_io_width directly
as the stride value, consistent with the Linux kernel.

Signed-off-by: David E. Garcia Porras <david.garcia@aheadcomputing.com>
---
 lib/utils/regmap/fdt_regmap_syscon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/utils/regmap/fdt_regmap_syscon.c b/lib/utils/regmap/fdt_regmap_syscon.c
index 1309a55c..59cd5ee5 100644
--- a/lib/utils/regmap/fdt_regmap_syscon.c
+++ b/lib/utils/regmap/fdt_regmap_syscon.c
@@ -190,7 +190,7 @@ static int regmap_syscon_init(const void *fdt, int nodeoff,
 
 	srm->rmap.id = nodeoff;
 	srm->rmap.reg_shift = 0;
-	srm->rmap.reg_stride = srm->reg_io_width * 8;
+	srm->rmap.reg_stride = srm->reg_io_width;
 	srm->rmap.reg_base = 0;
 	srm->rmap.reg_max = size / srm->reg_io_width;
 	switch (srm->reg_io_width) {
-- 
2.43.0


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                 reply	other threads:[~2026-04-03 20:29 UTC|newest]

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