[U-Boot] [PATCH 02/15 v2] spi: Add driver for Marvell Armada 3700 SoC

Stefan Roese sr at denx.de
Fri Sep 23 15:24:57 CEST 2016


On 23.09.2016 14:53, Jagan Teki wrote:
> On Fri, Sep 23, 2016 at 5:47 PM, Stefan Roese <sr at denx.de> wrote:
>> The SPI IP core in the Marvell Armada 3700 is similar to the one in the
>> other Armada SoCs. But the differences are big enough that it makes
>> sense to introduce a new driver instead of cluttering the old
>> kirkwood driver with #ifdef's.
>>
>> Signed-off-by: Stefan Roese <sr at denx.de>
>> Cc: Nadav Haklai <nadavh at marvell.com>
>> Cc: Kostya Porotchkin <kostap at marvell.com>
>> Cc: Wilson Ding <dingwei at marvell.com>
>> Cc: Victor Gu <xigu at marvell.com>
>> Cc: Hua Jing <jinghua at marvell.com>
>> Cc: Terry Zhou <bjzhou at marvell.com>
>> Cc: Hanna Hawa <hannah at marvell.com>
>> Cc: Haim Boot <hayim at marvell.com>
>> Cc: Jagan Teki <jteki at openedev.com>
>> ---
>> v2:
>> - Evaluated hz and used values provided by the DT in mvebu_spi_set_speed()
>>   as suggested by Jagan
>>
>>  drivers/spi/Kconfig           |   7 +
>>  drivers/spi/Makefile          |   1 +
>>  drivers/spi/mvebu_a3700_spi.c | 289 ++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 297 insertions(+)
>>  create mode 100644 drivers/spi/mvebu_a3700_spi.c
>>
>> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
>> index 5da66a6..8724f87 100644
>> --- a/drivers/spi/Kconfig
>> +++ b/drivers/spi/Kconfig
>> @@ -68,6 +68,13 @@ config ICH_SPI
>>           access the SPI NOR flash on platforms embedding this Intel
>>           ICH IP core.
>>
>> +config MVEBU_A3700_SPI
>> +       bool "Marvell Armada 3700 SPI driver"
>> +       help
>> +         Enable the Marvell Armada 3700 SPI driver. This driver can be
>> +         used to access the SPI NOR flash on platforms embedding this
>> +         Marvell IP core.
>> +
>>  config PIC32_SPI
>>         bool "Microchip PIC32 SPI driver"
>>         depends on MACH_PIC32
>> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
>> index b1d9e20..247c5f6 100644
>> --- a/drivers/spi/Makefile
>> +++ b/drivers/spi/Makefile
>> @@ -37,6 +37,7 @@ obj-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o
>>  obj-$(CONFIG_LPC32XX_SSP) += lpc32xx_ssp.o
>>  obj-$(CONFIG_MPC52XX_SPI) += mpc52xx_spi.o
>>  obj-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
>> +obj-$(CONFIG_MVEBU_A3700_SPI) += mvebu_a3700_spi.o
>>  obj-$(CONFIG_MXC_SPI) += mxc_spi.o
>>  obj-$(CONFIG_MXS_SPI) += mxs_spi.o
>>  obj-$(CONFIG_OMAP3_SPI) += omap3_spi.o
>> diff --git a/drivers/spi/mvebu_a3700_spi.c b/drivers/spi/mvebu_a3700_spi.c
>> new file mode 100644
>> index 0000000..b566e03
>> --- /dev/null
>> +++ b/drivers/spi/mvebu_a3700_spi.c
>> @@ -0,0 +1,289 @@
>> +/*
>> + * Copyright (C) 2015 Marvell International Ltd.
>> + *
>> + * Copyright (C) 2016 Stefan Roese <sr at denx.de>
>> + *
>> + * SPDX-License-Identifier:    GPL-2.0+
>> + */
>> +
>> +#include <common.h>
>> +#include <dm.h>
>> +#include <malloc.h>
>> +#include <spi.h>
>> +#include <wait_bit.h>
>> +#include <asm/io.h>
>> +
>> +DECLARE_GLOBAL_DATA_PTR;
>> +
>> +#define SPI_TIMEOUT                            10000
>> +
>> +#define MVEBU_SPI_A3700_XFER_RDY               BIT(1)
>> +#define MVEBU_SPI_A3700_FIFO_FLUSH             BIT(9)
>> +#define MVEBU_SPI_A3700_BYTE_LEN               BIT(5)
>> +#define MVEBU_SPI_A3700_CLK_PHA                        BIT(6)
>> +#define MVEBU_SPI_A3700_CLK_POL                        BIT(7)
>> +#define MVEBU_SPI_A3700_FIFO_EN                        BIT(17)
>> +#define MVEBU_SPI_A3700_SPI_EN_0               BIT(16)
>> +#define MVEBU_SPI_A3700_CLK_PRESCALE_BIT       0
>> +#define MVEBU_SPI_A3700_CLK_PRESCALE_MASK      \
>> +       (0x1f << MVEBU_SPI_A3700_CLK_PRESCALE_BIT)
>> +
>> +/* SPI registers */
>> +struct spi_reg {
>> +       u32 ctrl;       /* 0x10600 */
>> +       u32 cfg;        /* 0x10604 */
>> +       u32 dout;       /* 0x10608 */
>> +       u32 din;        /* 0x1060c */
>> +};
>> +
>> +struct mvebu_spi_platdata {
>> +       struct spi_reg *spireg;
>> +       unsigned int frequency;
>> +       unsigned int clock;
>> +};
>> +
>> +static void spi_cs_activate(struct spi_reg *reg, int cs)
>> +{
>> +       setbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
>> +}
>> +
>> +static void spi_cs_deactivate(struct spi_reg *reg, int cs)
>> +{
>> +       clrbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
>> +}
>> +
>> +/**
>> + * spi_legacy_shift_byte() - triggers the real SPI transfer
>> + * @bytelen:   Indicate how many bytes to transfer.
>> + * @dout:      Buffer address of what to send.
>> + * @din:       Buffer address of where to receive.
>> + *
>> + * This function triggers the real SPI transfer in legacy mode. It
>> + * will shift out char buffer from @dout, and shift in char buffer to
>> + * @din, if necessary.
>> + *
>> + * This function assumes that only one byte is shifted at one time.
>> + * However, it is not its responisbility to set the transfer type to
>> + * one-byte. Also, it does not guarantee that it will work if transfer
>> + * type becomes two-byte. See spi_set_legacy() for details.
>> + *
>> + * In legacy mode, simply write to the SPI_DOUT register will trigger
>> + * the transfer.
>> + *
>> + * If @dout == NULL, which means no actual data needs to be sent out,
>> + * then the function will shift out 0x00 in order to shift in data.
>> + * The XFER_RDY flag is checked every time before accessing SPI_DOUT
>> + * and SPI_DIN register.
>> + *
>> + * The number of transfers to be triggerred is decided by @bytelen.
>> + *
>> + * Return:     0 - cool
>> + *             -ETIMEDOUT - XFER_RDY flag timeout
>> + */
>> +static int spi_legacy_shift_byte(struct spi_reg *reg, unsigned int bytelen,
>> +                                const void *dout, void *din)
>> +{
>> +       const u8 *dout_8;
>> +       u8 *din_8;
>> +       int ret;
>> +
>> +       /* Use 0x00 as dummy dout */
>> +       const u8 dummy_dout = 0x0;
>> +       u32 pending_dout = 0x0;
>> +
>> +       /* dout_8: pointer of current dout */
>> +       dout_8 = dout;
>> +       /* din_8: pointer of current din */
>> +       din_8 = din;
>> +
>> +       while (bytelen) {
>> +               ret = wait_for_bit(__func__, &reg->ctrl,
>> +                                  MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
>> +               if (ret)
>> +                       return ret;
>> +
>> +               if (dout)
>> +                       pending_dout = (u32)*dout_8;
>> +               else
>> +                       pending_dout = (u32)dummy_dout;
>> +
>> +               /* Trigger the xfer */
>> +               writel(pending_dout, &reg->dout);
>> +
>> +               if (din) {
>> +                       ret = wait_for_bit(__func__, &reg->ctrl,
>> +                                          MVEBU_SPI_A3700_XFER_RDY,
>> +                                          true, 100, false);
>> +                       if (ret)
>> +                               return ret;
>> +
>> +                       /* Read what is transferred in */
>> +                       *din_8 = (u8)readl(&reg->din);
>> +               }
>> +
>> +               /* Don't increment the current pointer if NULL */
>> +               if (dout)
>> +                       dout_8++;
>> +               if (din)
>> +                       din_8++;
>> +
>> +               bytelen--;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int mvebu_spi_xfer(struct udevice *dev, unsigned int bitlen,
>> +                         const void *dout, void *din, unsigned long flags)
>> +{
>> +       struct udevice *bus = dev->parent;
>> +       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
>> +       struct spi_reg *reg = plat->spireg;
>> +       unsigned int bytelen;
>> +       int ret;
>> +
>> +       bytelen = bitlen / 8;
>> +
>> +       if (dout && din)
>> +               debug("This is a duplex transfer.\n");
>> +
>> +       /* Activate CS */
>> +       if (flags & SPI_XFER_BEGIN) {
>> +               debug("SPI: activate cs.\n");
>> +               spi_cs_activate(reg, spi_chip_select(dev));
>> +       }
>> +
>> +       /* Send and/or receive */
>> +       if (dout || din) {
>> +               ret = spi_legacy_shift_byte(reg, bytelen, dout, din);
>> +               if (ret)
>> +                       return ret;
>> +       }
>> +
>> +       /* Deactivate CS */
>> +       if (flags & SPI_XFER_END) {
>> +               ret = wait_for_bit(__func__, &reg->ctrl,
>> +                                  MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
>> +               if (ret)
>> +                       return ret;
>> +
>> +               debug("SPI: deactivate cs.\n");
>> +               spi_cs_deactivate(reg, spi_chip_select(dev));
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
>> +{
>> +       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
>> +       struct spi_reg *reg = plat->spireg;
>> +       u32 data;
>> +
>> +       data = readl(&reg->cfg);
>> +
>> +       /* Set Prescaler */
>> +       data &= ~MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
>> +
>> +       /* Calculate Prescaler = (spi_input_freq / spi_max_freq) */
>> +       if (hz > plat->frequency)
>> +               hz = plat->frequency;
>> +       data |= plat->clock / plat->frequency;
>
> Need to use the hz to compute here.

Yes, hz should be used instead of plat->frequency here. Will fix
in v3. Thanks for noticing.

>> +
>> +       writel(data, &reg->cfg);
>> +
>> +       return 0;
>> +}
>> +
>> +static int mvebu_spi_set_mode(struct udevice *bus, uint mode)
>> +{
>> +       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
>> +       struct spi_reg *reg = plat->spireg;
>> +
>> +       /*
>> +        * Set SPI polarity
>> +        * 0: Serial interface clock is low when inactive
>> +        * 1: Serial interface clock is high when inactive
>> +        */
>> +       if (mode & SPI_CPOL)
>> +               setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
>> +       else
>> +               clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
>> +       if (mode & SPI_CPHA)
>> +               setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
>> +       else
>> +               clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
>> +
>> +       return 0;
>> +}
>> +
>> +static int mvebu_spi_probe(struct udevice *bus)
>> +{
>> +       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
>> +       struct spi_reg *reg = plat->spireg;
>> +       u32 data;
>> +       int ret;
>> +
>> +       /*
>> +        * Settings SPI controller to be working in legacy mode, which
>> +        * means use only DO pin (I/O 1) for Data Out, and DI pin (I/O 0)
>> +        * for Data In.
>> +        */
>> +
>> +       /* Flush read/write FIFO */
>> +       data = readl(&reg->cfg);
>> +       writel(data | MVEBU_SPI_A3700_FIFO_FLUSH, &reg->cfg);
>> +       ret = wait_for_bit(__func__, &reg->cfg, MVEBU_SPI_A3700_FIFO_FLUSH,
>> +                          false, 1000, false);
>> +       if (ret)
>> +               return ret;
>> +
>> +       /* Disable FIFO mode */
>> +       data &= ~MVEBU_SPI_A3700_FIFO_EN;
>> +
>> +       /* Always shift 1 byte at a time */
>> +       data &= ~MVEBU_SPI_A3700_BYTE_LEN;
>> +
>> +       writel(data, &reg->cfg);
>> +
>> +       return 0;
>> +}
>> +
>> +static int mvebu_spi_ofdata_to_platdata(struct udevice *bus)
>> +{
>> +       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
>> +
>> +       plat->spireg = (struct spi_reg *)dev_get_addr(bus);
>> +
>> +       plat->clock = fdtdec_get_int(gd->fdt_blob, bus->of_offset,
>> +                                    "clock-frequency", 160000);
>
> I think this is not related to spi, global clock is it? usually we
> can't use clock-frequency we set the clock with the help of
> spi-max-frequency.

This is the input clock to the SPI IP core in the SoC. And
in most drivers I've seen so far, this frequency is configured
via some macros / defines. E.g.:

CONFIG_SYS_TCLK
CONFIG_CQSPI_REF_CLK
...

Best would be if this SPI input clock could be read via some
clock driver infrastructure. But this is something that we
don't have for MVEBU in U-Boot yet. So I can either switch back
to some define for this value here or leave it as the DT property
for now.

Thanks,
Stefan


More information about the U-Boot mailing list