From: Michael Walle <michael-QKn5cuLxLXY@public.gmane.org>
To: Vladimir Oltean <olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
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,
peng.ma-3arQi8VN3Tc@public.gmane.org
Subject: Re: [PATCH 2/6] spi: spi-fsl-dspi: Fix little endian access to PUSHR CMD and TXDATA
Date: Mon, 09 Mar 2020 18:59:04 +0100 [thread overview]
Message-ID: <d8e39e402328b962cdbc25316a27eac8@walle.cc> (raw)
In-Reply-To: <20200309145624.10026-3-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Am 2020-03-09 15:56, schrieb Vladimir Oltean:
> From: Vladimir Oltean <vladimir.oltean-3arQi8VN3Tc@public.gmane.org>
>
> 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 define the
> offsets per-instantiation, in the devtype_data structure. This means
> that we have to know from the driver which controllers are big- and
> which are little-endian (which is fine, we do, but it makes the device
> tree binding itself a little redundant except for regmap_config).
>
> This patch does not apply cleanly to stable trees, and a punctual fix
> to
> the commit cannot be provided given this constraint of lack of access
> to
> regmap_get_val_endian(). The per-SoC devtype_data structures (and
> therefore the premises to fix this bug) have been introduced only a few
> commits ago, in commit d35054010b57 ("spi: spi-fsl-dspi: Use specific
> compatible strings for all SoC instantiations")
>
> Fixes: 58ba07ec79e6 ("spi: spi-fsl-dspi: Add support for XSPI mode
> registers")
> Signed-off-by: Vladimir Oltean <vladimir.oltean-3arQi8VN3Tc@public.gmane.org>
> ---
> drivers/spi/spi-fsl-dspi.c | 28 ++++++++++++++++++++++------
> 1 file changed, 22 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index 0ce26c1cbf62..a8e56abe20ac 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 {
> @@ -124,6 +120,12 @@ struct fsl_dspi_devtype_data {
> u8 max_clock_factor;
> int fifo_size;
> int dma_bufsize;
> + /*
> + * Offsets for CMD and TXDATA within SPI_PUSHR when accessed
> + * individually (in XSPI mode)
> + */
> + int pushr_cmd;
> + int pushr_tx;
> };
Shouldn't this just read the "little-endian" property of the
device tree node? Like it worked before with regmap, which takes
the little-endian/big-endian property into account.
If I understand this correctly, this solution would mix the methods
how the IP endianess is determined. Eg. regmap_xx uses the
little-endian property and this driver then also uses the compatible
string to also distinguish between the endianess.
-michael
> enum {
> @@ -150,42 +152,56 @@ static const struct fsl_dspi_devtype_data
> devtype_data[] = {
> .trans_mode = DSPI_XSPI_MODE,
> .max_clock_factor = 8,
> .fifo_size = 4,
> + .pushr_cmd = 0,
> + .pushr_tx = 2,
> },
> [LS1012A] = {
> /* Has A-011218 DMA erratum */
> .trans_mode = DSPI_XSPI_MODE,
> .max_clock_factor = 8,
> .fifo_size = 16,
> + .pushr_cmd = 0,
> + .pushr_tx = 2,
> },
> [LS1043A] = {
> /* Has A-011218 DMA erratum */
> .trans_mode = DSPI_XSPI_MODE,
> .max_clock_factor = 8,
> .fifo_size = 16,
> + .pushr_cmd = 0,
> + .pushr_tx = 2,
> },
> [LS1046A] = {
> /* Has A-011218 DMA erratum */
> .trans_mode = DSPI_XSPI_MODE,
> .max_clock_factor = 8,
> .fifo_size = 16,
> + .pushr_cmd = 0,
> + .pushr_tx = 2,
> },
> [LS2080A] = {
> .trans_mode = DSPI_DMA_MODE,
> .dma_bufsize = 8,
> .max_clock_factor = 8,
> .fifo_size = 4,
> + .pushr_cmd = 2,
> + .pushr_tx = 0,
> },
> [LS2085A] = {
> .trans_mode = DSPI_DMA_MODE,
> .dma_bufsize = 8,
> .max_clock_factor = 8,
> .fifo_size = 4,
> + .pushr_cmd = 2,
> + .pushr_tx = 0,
> },
> [LX2160A] = {
> .trans_mode = DSPI_DMA_MODE,
> .dma_bufsize = 8,
> .max_clock_factor = 8,
> .fifo_size = 4,
> + .pushr_cmd = 2,
> + .pushr_tx = 0,
> },
> [MCF5441X] = {
> .trans_mode = DSPI_EOQ_MODE,
> @@ -670,12 +686,12 @@ 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->devtype_data->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->devtype_data->pushr_tx,
> txdata);
> }
>
> static void dspi_xspi_write(struct fsl_dspi *dspi, int cnt, bool eoq)
next prev parent reply other threads:[~2020-03-09 17:59 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 14:56 [PATCH 0/6] NXP DSPI bugfixes and support for LS1028A Vladimir Oltean
2020-03-09 14:56 ` [PATCH 1/6] spi: spi-fsl-dspi: Don't access reserved fields in SPI_MCR Vladimir Oltean
[not found] ` <20200309145624.10026-2-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-09 18:05 ` Michael Walle
[not found] ` <c35b3c34123b43b26204a2cf360e7ec1-QKn5cuLxLXY@public.gmane.org>
2020-03-09 18:09 ` Vladimir Oltean
2020-03-09 14:56 ` [PATCH 2/6] spi: spi-fsl-dspi: Fix little endian access to PUSHR CMD and TXDATA Vladimir Oltean
[not found] ` <20200309145624.10026-3-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-09 17:59 ` Michael Walle [this message]
[not found] ` <d8e39e402328b962cdbc25316a27eac8-QKn5cuLxLXY@public.gmane.org>
2020-03-09 18:07 ` Vladimir Oltean
[not found] ` <CA+h21hp4vC1c00rCgZo_hwQz3cE4dLBHjcgTHvf-+fS9a9VfxQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-03-09 18:19 ` Michael Walle
[not found] ` <a709dc91aac9124ed37ac1e7fcb7e105-QKn5cuLxLXY@public.gmane.org>
2020-03-09 18:31 ` Vladimir Oltean
2020-03-09 14:56 ` [PATCH 4/6] spi: spi-fsl-dspi: Add support for LS1028A Vladimir Oltean
[not found] ` <20200309145624.10026-5-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-09 18:38 ` Michael Walle
[not found] ` <02a2816d2f39bf621dfee543ed612ae0-QKn5cuLxLXY@public.gmane.org>
2020-03-09 18:51 ` Vladimir Oltean
[not found] ` <20200309145624.10026-1-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-09 14:56 ` [PATCH 3/6] spi: spi-fsl-dspi: Fix oper_word_size of zero for DMA mode Vladimir Oltean
2020-03-09 14:56 ` [PATCH 5/6] arm64: dts: ls1028a: Specify the DMA channels for the DSPI controllers Vladimir Oltean
[not found] ` <20200309145624.10026-6-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-09 19:06 ` Michael Walle
[not found] ` <83af52172a3cabd662de1ed9574e4247-QKn5cuLxLXY@public.gmane.org>
2020-03-09 19:59 ` Vladimir Oltean
2020-03-09 20:17 ` Michael Walle
2020-03-09 14:56 ` [PATCH 6/6] arm64: dts: ls1028a-rdb: Add a spidev node for the mikroBUS Vladimir Oltean
[not found] ` <20200309145624.10026-7-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2020-03-09 18:35 ` Michael Walle
[not found] ` <f213388d924b63d0fe265a2d731647be-QKn5cuLxLXY@public.gmane.org>
2020-03-09 18:50 ` Vladimir Oltean
[not found] ` <CA+h21hqOhM9+k9cKXoA8coYpxNFWpgD+FjETeB6uWLbsfrx0uw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-03-09 18:58 ` Michael Walle
2020-03-09 18:03 ` [PATCH 0/6] NXP DSPI bugfixes and support for LS1028A Michael Walle
[not found] ` <f530a0740f34b2cf26a8055d4eae2527-QKn5cuLxLXY@public.gmane.org>
2020-03-09 18:14 ` Vladimir Oltean
2020-03-09 18:31 ` Michael Walle
2020-03-09 18:48 ` Vladimir Oltean
[not found] ` <CA+h21hopP2XTx55iu_pG=xBx-TSPRBbdmoU7T2F0Gc9Qt=CsSQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-03-09 18:59 ` Michael Walle
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