linux-kernel - [PATCH 2/4] spi: cadence-qspi: set maximum chip-select to 4

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240209-cdns-qspi-cs-v1-2-a4f9dfed9ab4@bootlin.com>
Date: Fri, 09 Feb 2024 14:45:31 +0100
From: Théo Lebrun <theo.lebrun@...tlin.com>
To: Mark Brown <broonie@...nel.org>
Cc: linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Dhruva Gole <d-gole@...com>, Gregory CLEMENT <gregory.clement@...tlin.com>, 
 Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 Tawfik Bayouk <tawfik.bayouk@...ileye.com>, 
 Théo Lebrun <theo.lebrun@...tlin.com>
Subject: [PATCH 2/4] spi: cadence-qspi: set maximum chip-select to 4

Change the maximum chip-select count in cadence-qspi to 4 instead of 16.
The value gets used as default ->num_chipselect when the num-cs DT
property isn't received from devicetree. It also determines the
cqspi->f_pdata array size.

Hardware only supports values up to 4; see cqspi_chipselect() that sets
CS using a one-bit-per-CS 4-bit register field.

Add a static_assert() call as a defensive measure to ensure we stay
under the SPI subsystem limit. It got set to 4 when introduced in
4d8ff6b0991d ("spi: Add multi-cs memories support in SPI core") and
later increased to 16 in 2f8c7c3715f2 ("spi: Raise limit on number of
chip selects").

Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
---
 drivers/spi/spi-cadence-quadspi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 7ba4d5d16fd2..e9e3abd2142c 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -31,7 +31,9 @@
 #include <linux/timer.h>

 #define CQSPI_NAME			"cadence-qspi"
-#define CQSPI_MAX_CHIPSELECT		16
+#define CQSPI_MAX_CHIPSELECT		4
+
+static_assert(CQSPI_MAX_CHIPSELECT <= SPI_CS_CNT_MAX);

 /* Quirks */
 #define CQSPI_NEEDS_WR_DELAY		BIT(0)

-- 
2.43.0