From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Oltean Subject: [PATCH v3 3/7] spi: spi-fsl-dspi: Fix little endian access to PUSHR CMD and TXDATA Date: Tue, 10 Mar 2020 14:55:38 +0200 Message-ID: <20200310125542.5939-4-olteanv@gmail.com> References: <20200310125542.5939-1-olteanv@gmail.com> Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, eha-/iRVSOupHO4@public.gmane.org, angelo-BIYBQhTR83Y@public.gmane.org, andrew.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, gustavo-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org, weic-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, mhosny-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, michael-QKn5cuLxLXY@public.gmane.org, peng.ma-3arQi8VN3Tc@public.gmane.org To: broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Return-path: In-Reply-To: <20200310125542.5939-1-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: From: Vladimir Oltean In XSPI mode, the 32-bit PUSHR register can be written to separately: the higher 16 bits are for commands and the lower 16 bits are for data. This has nicely been hacked around, by defining a second regmap with a width of 16 bits, and effectively splitting a 32-bit register into 2 16-bit ones, from the perspective of this regmap_pushr. The problem is the assumption about the controller's endianness. If the controller is little endian (such as anything post-LS1046A), then the first 2 bytes, in the order imposed by memory layout, will actually hold the TXDATA, and the last 2 bytes will hold the CMD. So take the controller's endianness into account when performing split writes to PUSHR. The obvious and simple solution would have been to call regmap_get_val_endian(), but that is an internal regmap function and we don't want to change regmap just for this. Therefore, we just re-read the "big-endian" device tree property. Fixes: 58ba07ec79e6 ("spi: spi-fsl-dspi: Add support for XSPI mode registers") Signed-off-by: Vladimir Oltean --- Changes in v3: None. Changes in v2: Parse "big-endian" device tree bindings instead of taking the decision based on compatible SoC. drivers/spi/spi-fsl-dspi.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c index f2ba0731aebe..c59b68592283 100644 --- a/drivers/spi/spi-fsl-dspi.c +++ b/drivers/spi/spi-fsl-dspi.c @@ -103,10 +103,6 @@ #define SPI_FRAME_BITS(bits) SPI_CTAR_FMSZ((bits) - 1) #define SPI_FRAME_EBITS(bits) SPI_CTARE_FMSZE(((bits) - 1) >> 4) -/* Register offsets for regmap_pushr */ -#define PUSHR_CMD 0x0 -#define PUSHR_TX 0x2 - #define DMA_COMPLETION_TIMEOUT msecs_to_jiffies(3000) struct chip_data { @@ -240,6 +236,13 @@ struct fsl_dspi { int words_in_flight; + /* + * Offsets for CMD and TXDATA within SPI_PUSHR when accessed + * individually (in XSPI mode) + */ + int pushr_cmd; + int pushr_tx; + void (*host_to_dev)(struct fsl_dspi *dspi, u32 *txdata); void (*dev_to_host)(struct fsl_dspi *dspi, u32 rxdata); }; @@ -670,12 +673,12 @@ static void dspi_pushr_cmd_write(struct fsl_dspi *dspi, u16 cmd) */ if (dspi->len > dspi->oper_word_size) cmd |= SPI_PUSHR_CMD_CONT; - regmap_write(dspi->regmap_pushr, PUSHR_CMD, cmd); + regmap_write(dspi->regmap_pushr, dspi->pushr_cmd, cmd); } static void dspi_pushr_txdata_write(struct fsl_dspi *dspi, u16 txdata) { - regmap_write(dspi->regmap_pushr, PUSHR_TX, txdata); + regmap_write(dspi->regmap_pushr, dspi->pushr_tx, txdata); } static void dspi_xspi_write(struct fsl_dspi *dspi, int cnt, bool eoq) @@ -1269,6 +1272,7 @@ static int dspi_probe(struct platform_device *pdev) struct fsl_dspi *dspi; struct resource *res; void __iomem *base; + bool big_endian; ctlr = spi_alloc_master(&pdev->dev, sizeof(struct fsl_dspi)); if (!ctlr) @@ -1294,6 +1298,7 @@ static int dspi_probe(struct platform_device *pdev) /* Only Coldfire uses platform data */ dspi->devtype_data = &devtype_data[MCF5441X]; + big_endian = true; } else { ret = of_property_read_u32(np, "spi-num-chipselects", &cs_num); @@ -1315,6 +1320,15 @@ static int dspi_probe(struct platform_device *pdev) ret = -EFAULT; goto out_ctlr_put; } + + big_endian = of_device_is_big_endian(np); + } + if (big_endian) { + dspi->pushr_cmd = 0; + dspi->pushr_tx = 2; + } else { + dspi->pushr_cmd = 2; + dspi->pushr_tx = 0; } if (dspi->devtype_data->trans_mode == DSPI_XSPI_MODE) -- 2.17.1