[PATCH 6.1 1063/1191] i3c: mipi-i3c-hci: Fix DAT/DCT entry sizes

From
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date
2026-09-12 16:52:44
Also in
linux-patches
Reply to
Greg Kroah-Hartman, 2026-09-12
6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jarkko Nikula <redacted>

[ Upstream commit 0676bfebf5766f0a60549f74ba597115028fa39c ]

MIPI I3C HCI specification v1.1 describes the ENTRY_SIZE field for the
Device Address Table (DAT) and the Device Characteristics Table (DCT)
section offset registers (DAT_SECTION_OFFSET and DCT_SECTION_OFFSET).
That field is not documented in earlier version.

ENTRY_SIZE value 0 is meant to be backward compatible. For the DAT entry
size it is interpreted as 2 DWORDs (8-bytes) and for the DCT entry size
as 4 DWORDs (16-bytes). Values 1-15 are reserved for future use.

New version I believe fixes also the TABLE_SIZE field description.
Before it was defined in DWORDs which I believe is incorrect since the
DAT/DCT table entry structures, and sizes, are described having
8-bytes/16-bytes entries.

This is more clear in the specification v1.1 which states the TABLE_SIZE
fields are interpreted as number of entries in the DAT/DCT tables. I
believe this same holds also in earlier version, at least it makes more
sense.

Fix code accordingly and let the DAT_entry_size and the DCT_entry_size
variables carry the size as bytes. Which is how it is already
interpreted in the dat_v1.c: hci_dat_v1_init().

Signed-off-by: Jarkko Nikula <redacted>
Link: https://lore.kernel.org/r/20230921055704.1087277-4-jarkko.nikula@linux.intel.com (local)
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Stable-dep-of: 308ecb824db3 ("i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i3c/master/mipi-i3c-hci/core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index d3f9d14c32f33..8622125ad3e4e 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -610,17 +610,17 @@ static int i3c_hci_init(struct i3c_hci *hci)
 	offset = FIELD_GET(DAT_TABLE_OFFSET, regval);
 	hci->DAT_regs = offset ? hci->base_regs + offset : NULL;
 	hci->DAT_entries = FIELD_GET(DAT_TABLE_SIZE, regval);
-	hci->DAT_entry_size = FIELD_GET(DAT_ENTRY_SIZE, regval);
+	hci->DAT_entry_size = FIELD_GET(DAT_ENTRY_SIZE, regval) ? 0 : 8;
 	dev_info(&hci->master.dev, "DAT: %u %u-bytes entries at offset %#x\n",
-		 hci->DAT_entries, hci->DAT_entry_size * 4, offset);
+		 hci->DAT_entries, hci->DAT_entry_size, offset);
 
 	regval = reg_read(DCT_SECTION);
 	offset = FIELD_GET(DCT_TABLE_OFFSET, regval);
 	hci->DCT_regs = offset ? hci->base_regs + offset : NULL;
 	hci->DCT_entries = FIELD_GET(DCT_TABLE_SIZE, regval);
-	hci->DCT_entry_size = FIELD_GET(DCT_ENTRY_SIZE, regval);
+	hci->DCT_entry_size = FIELD_GET(DCT_ENTRY_SIZE, regval) ? 0 : 16;
 	dev_info(&hci->master.dev, "DCT: %u %u-bytes entries at offset %#x\n",
-		 hci->DCT_entries, hci->DCT_entry_size * 4, offset);
+		 hci->DCT_entries, hci->DCT_entry_size, offset);
 
 	regval = reg_read(RING_HEADERS_SECTION);
 	offset = FIELD_GET(RING_HEADERS_OFFSET, regval);
-- 
2.53.0


Thread (1,211 messages) 1,211 messages, 13 authors, last reply 2026-09-21
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