[U-Boot] [PATCH v2 17/18] spi: mtk_qspi: add qspi driver for MT7629 SoC

[Guochun Mao]

On Wed, 2018-11-14 at 14:34 +0530, Jagan Teki wrote:
> On Fri, Oct 12, 2018 at 12:46 PM Ryder Lee <ryder.lee at mediatek.com> wrote:
> >
> > From: Guochun Mao <guochun.mao at mediatek.com>
> >
> > This patch adds MT7629 qspi driver for accessing SPI NOR flash.
> >
> > Cc: Jagan Teki <jagan at openedev.com>
> > Signed-off-by: Guochun Mao <guochun.mao at mediatek.com>
> > ---
> > change since v2:
> > - Drop flash commands in the driver.
> > ---
> >  drivers/spi/Kconfig    |   7 +
> >  drivers/spi/Makefile   |   1 +
> >  drivers/spi/mtk_qspi.c | 359 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 367 insertions(+)
> >  create mode 100644 drivers/spi/mtk_qspi.c
> >
> > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> > index 1df6876..f9cf4ba 100644
> > --- a/drivers/spi/Kconfig
> > +++ b/drivers/spi/Kconfig
> > @@ -124,6 +124,13 @@ config MT7621_SPI
> >           the SPI NOR flash on platforms embedding this Ralink / MediaTek
> >           SPI core, like MT7621/7628/7688.
> >
> > +config MTK_QSPI
> > +       bool "Mediatek QSPI driver"
> > +       help
> > +         Enable the Mediatek QSPI driver. This driver can be
> > +         used to access the SPI NOR flash on platforms embedding this
> > +         Mediatek QSPI IP core.
> > +
> >  config MVEBU_A3700_SPI
> >         bool "Marvell Armada 3700 SPI driver"
> >         select CLK_ARMADA_3720
> > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> > index 7242ea7..e5a78f5 100644
> > --- a/drivers/spi/Makefile
> > +++ b/drivers/spi/Makefile
> > @@ -33,6 +33,7 @@ obj-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o
> >  obj-$(CONFIG_LPC32XX_SSP) += lpc32xx_ssp.o
> >  obj-$(CONFIG_MPC8XX_SPI) += mpc8xx_spi.o
> >  obj-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
> > +obj-$(CONFIG_MTK_QSPI) += mtk_qspi.o
> >  obj-$(CONFIG_MT7621_SPI) += mt7621_spi.o
> >  obj-$(CONFIG_MVEBU_A3700_SPI) += mvebu_a3700_spi.o
> >  obj-$(CONFIG_MXC_SPI) += mxc_spi.o
> > diff --git a/drivers/spi/mtk_qspi.c b/drivers/spi/mtk_qspi.c
> > new file mode 100644
> > index 0000000..b510733
> > --- /dev/null
> > +++ b/drivers/spi/mtk_qspi.c
> > @@ -0,0 +1,359 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2018  MediaTek, Inc.
> > + * Author : Guochun.Mao at mediatek.com
> > + */
> > +
> > +#include <common.h>
> > +#include <dm.h>
> > +#include <malloc.h>
> > +#include <spi.h>
> > +#include <asm/io.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/ioport.h>
> > +
> > +/* Register Offset */
> > +struct mtk_qspi_regs {
> > +       u32 cmd;
> > +       u32 cnt;
> > +       u32 rdsr;
> > +       u32 rdata;
> > +       u32 radr[3];
> > +       u32 wdata;
> > +       u32 prgdata[6];
> > +       u32 shreg[10];
> > +       u32 cfg[2];
> > +       u32 shreg10;
> > +       u32 mode_mon;
> > +       u32 status[4];
> > +       u32 flash_time;
> > +       u32 flash_cfg;
> > +       u32 reserved_0[3];
> > +       u32 sf_time;
> > +       u32 pp_dw_data;
> > +       u32 reserved_1;
> > +       u32 delsel_0[2];
> > +       u32 intrstus;
> > +       u32 intren;
> > +       u32 reserved_2;
> > +       u32 cfg3;
> > +       u32 reserved_3;
> > +       u32 chksum;
> > +       u32 aaicmd;
> > +       u32 wrprot;
> > +       u32 radr3;
> > +       u32 dual;
> > +       u32 delsel_1[3];
> > +};
> > +
> > +struct mtk_qspi_platdata {
> > +       fdt_addr_t reg_base;
> > +       fdt_addr_t mem_base;
> > +};
> > +
> > +struct mtk_qspi_priv {
> > +       struct mtk_qspi_regs *regs;
> > +       unsigned long *mem_base;
> > +       u8 op;
> > +       u8 tx[3]; /* only record max 3 bytes paras, when it's address. */
> > +       u32 txlen; /* dout buffer length  - op code length */
> > +       u8 *rx;
> > +       u32 rxlen;
> > +};
> > +
> > +#define MTK_QSPI_CMD_POLLINGREG_US 500000
> > +#define MTK_QSPI_WRBUF_SIZE        256
> > +#define MTK_QSPI_COMMAND_ENABLE    0x30
> > +
> > +/* NOR flash controller commands */
> > +#define MTK_QSPI_RD_TRIGGER        BIT(0)
> > +#define MTK_QSPI_READSTATUS        BIT(1)
> > +#define MTK_QSPI_PRG_CMD           BIT(2)
> > +#define MTK_QSPI_WR_TRIGGER        BIT(4)
> > +#define MTK_QSPI_WRITESTATUS       BIT(5)
> > +#define MTK_QSPI_AUTOINC           BIT(7)
> > +
> > +#define MTK_QSPI_MAX_RX_TX_SHIFT   0x6
> > +#define MTK_QSPI_MAX_SHIFT         0x8
> > +
> > +#define MTK_QSPI_WR_BUF_ENABLE     0x1
> > +#define MTK_QSPI_WR_BUF_DISABLE    0x0
> 
> All these bits look flash handling bit's , aren't ?
> 
> > +
> > +static int mtk_qspi_execute_cmd(struct mtk_qspi_priv *priv, u8 cmd)
> > +{
> > +       u8 tmp;
> > +       u8 val = cmd & ~MTK_QSPI_AUTOINC;
> > +
> > +       writeb(cmd, &priv->regs->cmd);
> > +
> > +       return readb_poll_timeout(&priv->regs->cmd, tmp, !(val & tmp),
> > +                                 MTK_QSPI_CMD_POLLINGREG_US);
> > +}
> > +
> > +static int mtk_qspi_tx_rx(struct mtk_qspi_priv *priv)
> > +{
> > +       int len = 1 + priv->txlen + priv->rxlen;
> > +       int i, ret, idx;
> > +
> > +       if (len > MTK_QSPI_MAX_SHIFT)
> > +               return -ERR_INVAL;
> > +
> > +       writeb(len * 8, &priv->regs->cnt);
> > +
> > +       /* start at PRGDATA5, go down to PRGDATA0 */
> > +       idx = MTK_QSPI_MAX_RX_TX_SHIFT - 1;
> > +
> > +       /* opcode */
> > +       writeb(priv->op, &priv->regs->prgdata[idx]);
> > +       idx--;
> > +
> > +       /* program TX data */
> > +       for (i = 0; i < priv->txlen; i++, idx--)
> > +               writeb(priv->tx[i], &priv->regs->prgdata[idx]);
> > +
> > +       /* clear out rest of TX registers */
> > +       while (idx >= 0) {
> > +               writeb(0, &priv->regs->prgdata[idx]);
> > +               idx--;
> > +       }
> > +
> > +       ret = mtk_qspi_execute_cmd(priv, MTK_QSPI_PRG_CMD);
> 
> What does this execute do? 
It send command to flash, and latch data if need.

> does it intiate the controller register
> based flash command or so?
No, it doesn't.

> 
> Do you have Linux driver on the controller?
Yes, it's drivers/mtd/spi-nor/mtk-quadspi.c

BR,
Guochun