From: Viken Dadhaniya Date: Tue, 9 Jun 2026 08:43:09 +0000 (+0530) Subject: spi: qcom-geni: Fix cs_change handling on the last transfer X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=5ac5ec84734fd338867055d4d7b650f18a023cb0;p=thirdparty%2Fkernel%2Flinux.git spi: qcom-geni: Fix cs_change handling on the last transfer TPM TIS SPI probe fails with: tpm_tis_spi: probe of spi11.0 failed with error -110 TPM TIS SPI sets cs_change=1 on single-transfer messages to keep CS asserted across the header, wait-state, and data phases of a transaction. CS deassertion between these phases violates the TCG SPI flow control specification. This bug was introduced by commit b99181cdf9fa ("spi-geni-qcom: remove manual CS control"), which replaced manual CS control with automatic CS control via the FRAGMENTATION bit. The FRAGMENTATION bit controls CS behavior after a transfer: when set to 1, CS remains asserted; when cleared to 0, CS is deasserted. The commit correctly sets FRAGMENTATION for non-last transfers with cs_change=0 to keep CS asserted between chained transfers, but misses the case where cs_change=1 is set on the last transfer. When cs_change=1 on the last transfer, the client requests CS to remain asserted after the message completes, so FRAGMENTATION must be set to 1 in this case as well. Fix setup_se_xfer() to set FRAGMENTATION when cs_change=1 on the last transfer. Also fix the same missing case in setup_gsi_xfer() and correct it to write 1 instead of the raw bitmask FRAGMENTATION (value 4) to peripheral.fragmentation. This field is a 1-bit boolean consumed by gpi_create_spi_tre() via u32_encode_bits(..., TRE_SPI_GO_FRAG). Writing 4 to a 1-bit field causes u32_encode_bits() to mask it to 0, silently disabling the FRAGMENTATION bit in the GPI TRE regardless of the cs_change logic. Fixes: b99181cdf9fa ("spi-geni-qcom: remove manual CS control") Cc: stable@vger.kernel.org Reviewed-by: Jonathan Marek Signed-off-by: Viken Dadhaniya Link: https://patch.msgid.link/20260609-fix-spi-fragmentation-bit-logic-v2-1-e18efc255563@oss.qualcomm.com Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c index d5fb0edc8e0c..23c6d3a37341 100644 --- a/drivers/spi/spi-geni-qcom.c +++ b/drivers/spi/spi-geni-qcom.c @@ -440,10 +440,15 @@ static int setup_gsi_xfer(struct spi_transfer *xfer, struct spi_geni_master *mas return ret; } - if (!xfer->cs_change) { - if (!list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers)) - peripheral.fragmentation = FRAGMENTATION; - } + /* + * Set fragmentation to keep CS asserted after this transfer when: + * - non-last transfer with cs_change=0: keep CS asserted between chained transfers + * - last transfer with cs_change=1: keep CS asserted after the message + * (e.g. TPM TIS SPI uses cs_change=1 on single-transfer messages to + * keep CS asserted across header, wait-state and data phases) + */ + peripheral.fragmentation = list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers) ? + xfer->cs_change : !xfer->cs_change; if (peripheral.cmd & SPI_RX) { dmaengine_slave_config(mas->rx, &config); @@ -849,10 +854,16 @@ static int setup_se_xfer(struct spi_transfer *xfer, mas->cur_xfer_mode = GENI_SE_DMA; geni_se_select_mode(se, mas->cur_xfer_mode); - if (!xfer->cs_change) { - if (!list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers)) - m_params = FRAGMENTATION; - } + /* + * Set FRAGMENTATION to keep CS asserted after this transfer when: + * - non-last transfer with cs_change=0: keep CS asserted between chained transfers + * - last transfer with cs_change=1: keep CS asserted after the message + * (e.g. TPM TIS SPI uses cs_change=1 on single-transfer messages to + * keep CS asserted across header, wait-state and data phases) + */ + if (list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers) ? + xfer->cs_change : !xfer->cs_change) + m_params = FRAGMENTATION; /* * Lock around right before we start the transfer since our