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Date: Fri, 12 Nov 2021 23:23:54 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Serge Semin <Sergey.Semin@...kalelectronics.ru>
Cc: Serge Semin <fancer.lancer@...il.com>,
Mark Brown <broonie@...nel.org>,
Nandhini Srikandan <nandhini.srikandan@...el.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Andy Shevchenko <andy@...nel.org>,
linux-spi <linux-spi@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/4] spi: dw: Convert to using the Bitfield access macros
On Fri, Nov 12, 2021 at 10:51 PM Serge Semin
<Sergey.Semin@...kalelectronics.ru> wrote:
>
> The driver has been using the offset/bitwise-shift-based approach for the
> CSR fields R/W operations since it was merged into the kernel. It can be
> simplified by using the macros defined in the linux/bitfield.h and
> linux/bit.h header files like BIT(), GENMASK(), FIELD_PREP(), FIELD_GET(),
> etc where it is required, for instance in the cached cr0 preparation
> method. Thus in order to have the FIELD_*()-macros utilized we just need
> to convert the macros with the CSR-fields offsets to the masks with the
> corresponding registers fields definition. That's where the GENMASK() and
> BIT() macros come in handy. After that the masks can be used in the
> FIELD_*()-macros where it's appropriate.
>
> We also need to convert the macros with the CRS-bit flags using the manual
> bitwise shift operations (x << y) to using the BIT() macro. Thus we'll
> have a more coherent set of the CSR-related macros.
>
> Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
> ---
> drivers/spi/spi-dw-core.c | 31 +++++++++++--------
> drivers/spi/spi-dw.h | 64 +++++++++++++++++++--------------------
> 2 files changed, 50 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
> index 4d91ffb5c0d8..b4cbcd38eaba 100644
> --- a/drivers/spi/spi-dw-core.c
> +++ b/drivers/spi/spi-dw-core.c
> @@ -5,6 +5,7 @@
> * Copyright (c) 2009, Intel Corporation.
> */
>
> +#include <linux/bitfield.h>
> #include <linux/dma-mapping.h>
> #include <linux/interrupt.h>
> #include <linux/module.h>
> @@ -254,7 +255,7 @@ static irqreturn_t dw_spi_irq(int irq, void *dev_id)
> {
> struct spi_controller *master = dev_id;
> struct dw_spi *dws = spi_controller_get_devdata(master);
> - u16 irq_status = dw_readl(dws, DW_SPI_ISR) & 0x3f;
> + u16 irq_status = dw_readl(dws, DW_SPI_ISR) & DW_SPI_INT_MASK;
>
> if (!irq_status)
> return IRQ_NONE;
> @@ -273,32 +274,38 @@ static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi)
>
> if (!(dws->caps & DW_SPI_CAP_DWC_HSSI)) {
> /* CTRLR0[ 5: 4] Frame Format */
> - cr0 |= DW_SPI_CTRLR0_FRF_MOTO_SPI << DW_PSSI_CTRLR0_FRF_OFFSET;
> + cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
>
> /*
> * SPI mode (SCPOL|SCPH)
> * CTRLR0[ 6] Serial Clock Phase
> * CTRLR0[ 7] Serial Clock Polarity
> */
> - cr0 |= ((spi->mode & SPI_CPOL) ? 1 : 0) << DW_PSSI_CTRLR0_SCOL_OFFSET;
> - cr0 |= ((spi->mode & SPI_CPHA) ? 1 : 0) << DW_PSSI_CTRLR0_SCPH_OFFSET;
> + if (spi->mode & SPI_CPOL)
> + cr0 |= DW_PSSI_CTRLR0_SCPOL;
> + if (spi->mode & SPI_CPHA)
> + cr0 |= DW_PSSI_CTRLR0_SCPHA;
>
> /* CTRLR0[11] Shift Register Loop */
> - cr0 |= ((spi->mode & SPI_LOOP) ? 1 : 0) << DW_PSSI_CTRLR0_SRL_OFFSET;
> + if (spi->mode & SPI_LOOP)
> + cr0 |= DW_PSSI_CTRLR0_SRL;
> } else {
> /* CTRLR0[ 7: 6] Frame Format */
> - cr0 |= DW_SPI_CTRLR0_FRF_MOTO_SPI << DW_HSSI_CTRLR0_FRF_OFFSET;
> + cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
>
> /*
> * SPI mode (SCPOL|SCPH)
> * CTRLR0[ 8] Serial Clock Phase
> * CTRLR0[ 9] Serial Clock Polarity
> */
> - cr0 |= ((spi->mode & SPI_CPOL) ? 1 : 0) << DW_HSSI_CTRLR0_SCPOL_OFFSET;
> - cr0 |= ((spi->mode & SPI_CPHA) ? 1 : 0) << DW_HSSI_CTRLR0_SCPH_OFFSET;
> + if (spi->mode & SPI_CPOL)
> + cr0 |= DW_HSSI_CTRLR0_SCPOL;
> + if (spi->mode & SPI_CPHA)
> + cr0 |= DW_HSSI_CTRLR0_SCPHA;
>
> /* CTRLR0[13] Shift Register Loop */
> - cr0 |= ((spi->mode & SPI_LOOP) ? 1 : 0) << DW_HSSI_CTRLR0_SRL_OFFSET;
> + if (spi->mode & SPI_LOOP)
> + cr0 |= DW_HSSI_CTRLR0_SRL;
>
> if (dws->caps & DW_SPI_CAP_KEEMBAY_MST)
> cr0 |= DW_HSSI_CTRLR0_KEEMBAY_MST;
> @@ -320,10 +327,10 @@ void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
>
> if (!(dws->caps & DW_SPI_CAP_DWC_HSSI))
> /* CTRLR0[ 9:8] Transfer Mode */
> - cr0 |= cfg->tmode << DW_PSSI_CTRLR0_TMOD_OFFSET;
> + cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_TMOD_MASK, cfg->tmode);
> else
> /* CTRLR0[11:10] Transfer Mode */
> - cr0 |= cfg->tmode << DW_HSSI_CTRLR0_TMOD_OFFSET;
> + cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_TMOD_MASK, cfg->tmode);
>
> dw_writel(dws, DW_SPI_CTRLR0, cr0);
>
> @@ -850,7 +857,7 @@ static void dw_spi_hw_init(struct device *dev, struct dw_spi *dws)
>
> if (!(cr0 & DW_PSSI_CTRLR0_DFS_MASK)) {
> dws->caps |= DW_SPI_CAP_DFS32;
> - dws->dfs_offset = DW_PSSI_CTRLR0_DFS32_OFFSET;
> + dws->dfs_offset = __bf_shf(DW_PSSI_CTRLR0_DFS32_MASK);
> dev_dbg(dev, "Detected 32-bits max data frame size\n");
> }
> } else {
> diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
> index 893b78c43a50..634085eadad1 100644
> --- a/drivers/spi/spi-dw.h
> +++ b/drivers/spi/spi-dw.h
Haven't deeply checked this, but below changes require to have bits.h
to be included.
Please, double check this is included already.
> @@ -41,39 +41,36 @@
> #define DW_SPI_CS_OVERRIDE 0xf4
>
> /* Bit fields in CTRLR0 (DWC APB SSI) */
> -#define DW_PSSI_CTRLR0_DFS_OFFSET 0
> #define DW_PSSI_CTRLR0_DFS_MASK GENMASK(3, 0)
> -#define DW_PSSI_CTRLR0_DFS32_OFFSET 16
> +#define DW_PSSI_CTRLR0_DFS32_MASK GENMASK(20, 16)
>
> -#define DW_PSSI_CTRLR0_FRF_OFFSET 4
> +#define DW_PSSI_CTRLR0_FRF_MASK GENMASK(5, 4)
> #define DW_SPI_CTRLR0_FRF_MOTO_SPI 0x0
> #define DW_SPI_CTRLR0_FRF_TI_SSP 0x1
> #define DW_SPI_CTRLR0_FRF_NS_MICROWIRE 0x2
> #define DW_SPI_CTRLR0_FRF_RESV 0x3
>
> -#define DW_PSSI_CTRLR0_MODE_OFFSET 6
> -#define DW_PSSI_CTRLR0_SCPH_OFFSET 6
> -#define DW_PSSI_CTRLR0_SCOL_OFFSET 7
> +#define DW_PSSI_CTRLR0_MODE_MASK GENMASK(7, 6)
> +#define DW_PSSI_CTRLR0_SCPHA BIT(6)
> +#define DW_PSSI_CTRLR0_SCPOL BIT(7)
>
> -#define DW_PSSI_CTRLR0_TMOD_OFFSET 8
> -#define DW_PSSI_CTRLR0_TMOD_MASK (0x3 << DW_PSSI_CTRLR0_TMOD_OFFSET)
> +#define DW_PSSI_CTRLR0_TMOD_MASK GENMASK(9, 8)
> #define DW_SPI_CTRLR0_TMOD_TR 0x0 /* xmit & recv */
> #define DW_SPI_CTRLR0_TMOD_TO 0x1 /* xmit only */
> #define DW_SPI_CTRLR0_TMOD_RO 0x2 /* recv only */
> #define DW_SPI_CTRLR0_TMOD_EPROMREAD 0x3 /* eeprom read mode */
>
> -#define DW_PSSI_CTRLR0_SLVOE_OFFSET 10
> -#define DW_PSSI_CTRLR0_SRL_OFFSET 11
> -#define DW_PSSI_CTRLR0_CFS_OFFSET 12
> +#define DW_PSSI_CTRLR0_SLV_OE BIT(10)
> +#define DW_PSSI_CTRLR0_SRL BIT(11)
> +#define DW_PSSI_CTRLR0_CFS BIT(12)
>
> /* Bit fields in CTRLR0 (DWC SSI with AHB interface) */
> -#define DW_HSSI_CTRLR0_SRL_OFFSET 13
> -#define DW_HSSI_CTRLR0_TMOD_OFFSET 10
> +#define DW_HSSI_CTRLR0_DFS_MASK GENMASK(4, 0)
> +#define DW_HSSI_CTRLR0_FRF_MASK GENMASK(7, 6)
> +#define DW_HSSI_CTRLR0_SCPHA BIT(8)
> +#define DW_HSSI_CTRLR0_SCPOL BIT(9)
> #define DW_HSSI_CTRLR0_TMOD_MASK GENMASK(11, 10)
> -#define DW_HSSI_CTRLR0_SCPOL_OFFSET 9
> -#define DW_HSSI_CTRLR0_SCPH_OFFSET 8
> -#define DW_HSSI_CTRLR0_FRF_OFFSET 6
> -#define DW_HSSI_CTRLR0_DFS_OFFSET 0
> +#define DW_HSSI_CTRLR0_SRL BIT(13)
>
> /*
> * For Keem Bay, CTRLR0[31] is used to select controller mode.
> @@ -86,26 +83,27 @@
> #define DW_SPI_NDF_MASK GENMASK(15, 0)
>
> /* Bit fields in SR, 7 bits */
> -#define DW_SPI_SR_MASK 0x7f /* cover 7 bits */
> -#define DW_SPI_SR_BUSY (1 << 0)
> -#define DW_SPI_SR_TF_NOT_FULL (1 << 1)
> -#define DW_SPI_SR_TF_EMPT (1 << 2)
> -#define DW_SPI_SR_RF_NOT_EMPT (1 << 3)
> -#define DW_SPI_SR_RF_FULL (1 << 4)
> -#define DW_SPI_SR_TX_ERR (1 << 5)
> -#define DW_SPI_SR_DCOL (1 << 6)
> +#define DW_SPI_SR_MASK GENMASK(6, 0)
> +#define DW_SPI_SR_BUSY BIT(0)
> +#define DW_SPI_SR_TF_NOT_FULL BIT(1)
> +#define DW_SPI_SR_TF_EMPT BIT(2)
> +#define DW_SPI_SR_RF_NOT_EMPT BIT(3)
> +#define DW_SPI_SR_RF_FULL BIT(4)
> +#define DW_SPI_SR_TX_ERR BIT(5)
> +#define DW_SPI_SR_DCOL BIT(6)
>
> /* Bit fields in ISR, IMR, RISR, 7 bits */
> -#define DW_SPI_INT_TXEI (1 << 0)
> -#define DW_SPI_INT_TXOI (1 << 1)
> -#define DW_SPI_INT_RXUI (1 << 2)
> -#define DW_SPI_INT_RXOI (1 << 3)
> -#define DW_SPI_INT_RXFI (1 << 4)
> -#define DW_SPI_INT_MSTI (1 << 5)
> +#define DW_SPI_INT_MASK GENMASK(5, 0)
> +#define DW_SPI_INT_TXEI BIT(0)
> +#define DW_SPI_INT_TXOI BIT(1)
> +#define DW_SPI_INT_RXUI BIT(2)
> +#define DW_SPI_INT_RXOI BIT(3)
> +#define DW_SPI_INT_RXFI BIT(4)
> +#define DW_SPI_INT_MSTI BIT(5)
>
> /* Bit fields in DMACR */
> -#define DW_SPI_DMACR_RDMAE (1 << 0)
> -#define DW_SPI_DMACR_TDMAE (1 << 1)
> +#define DW_SPI_DMACR_RDMAE BIT(0)
> +#define DW_SPI_DMACR_TDMAE BIT(1)
>
> /* Mem/DMA operations helpers */
> #define DW_SPI_WAIT_RETRIES 5
> --
> 2.33.0
>
--
With Best Regards,
Andy Shevchenko
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