From: CL Wang Date: Tue, 3 Mar 2026 02:47:37 +0000 (+0800) Subject: spi: atcspi200: Handle invalid buswidth and fix compiler warning X-Git-Tag: v7.0-rc4~26^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f879365c5bb210ed0d0b0aae1a0202d0c0b4b9d0;p=thirdparty%2Fkernel%2Flinux.git spi: atcspi200: Handle invalid buswidth and fix compiler warning The kernel test robot reported a compile-time error regarding the FIELD_PREP() value being too large for the TRANS_DUAL_QUAD field: error: FIELD_PREP: value too large for the field note: in expansion of macro 'TRANS_DUAL_QUAD' tc |= TRANS_DUAL_QUAD(ffs(op->data.buswidth) - 1); This occurs because TRANS_DUAL_QUAD is defined as a 2-bit field, and GCC's static analysis cannot deduce that `ffs(op->data.buswidth) - 1` will strictly fall within the 0~3 range. Although the SPI framework guarantees that `op->data.buswidth` is valid at runtime (e.g., 1, 2, 4, 8), an explicit bounds check is necessary to satisfy the compiler. To resolve the build warning, introduce a safe fallback mechanism. If an unexpected buswidth is encountered, the driver will trigger a WARN_ON_ONCE to leave a trace and fall back to width_code = 0 (standard 1-bit SPI mode). This approach guarantees predictable hardware behavior. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202602140738.P7ZozxzI-lkp@intel.com/ Suggested-by: Pei Xiao Signed-off-by: CL Wang Link: https://patch.msgid.link/20260303024737.1791196-1-cl634@andestech.com Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi-atcspi200.c b/drivers/spi/spi-atcspi200.c index fef6954d27e1..2665f31a49ce 100644 --- a/drivers/spi/spi-atcspi200.c +++ b/drivers/spi/spi-atcspi200.c @@ -195,7 +195,15 @@ static void atcspi_set_trans_ctl(struct atcspi_dev *spi, if (op->addr.buswidth > 1) tc |= TRANS_ADDR_FMT; if (op->data.nbytes) { - tc |= TRANS_DUAL_QUAD(ffs(op->data.buswidth) - 1); + unsigned int width_code; + + width_code = ffs(op->data.buswidth) - 1; + if (unlikely(width_code > 3)) { + WARN_ON_ONCE(1); + width_code = 0; + } + tc |= TRANS_DUAL_QUAD(width_code); + if (op->data.dir == SPI_MEM_DATA_IN) { if (op->dummy.nbytes) tc |= TRANS_MODE_DMY_READ |