Hi,
just some small comments.
On 14 May 2012 19:42, John Crispin <blogic@xxxxxxxxxxx> wrote:
> The external bus unit (EBU) found on the FALCON SoC has spi emulation that is
> designed for serial flash access. This driver has only been tested with m25p80
> type chips. The hardware has no support for other types of spi peripherals.
>
> Signed-off-by: Thomas Langer <thomas.langer@xxxxxxxxxx>
> Signed-off-by: John Crispin <blogic@xxxxxxxxxxx>
> Cc: spi-devel-general@xxxxxxxxxxxxxxxxxxxxx
> ---
> This patch is part of a series moving the mips/lantiq target to OF and clkdev
> support. The patch, once Acked, should go upstream via Ralf's MIPS tree.
>
> drivers/spi/Kconfig | 9 +
> drivers/spi/Makefile | 1 +
> drivers/spi/spi-falcon.c | 473 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 483 insertions(+), 0 deletions(-)
> create mode 100644 drivers/spi/spi-falcon.c
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 00c0240..2afb8db 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -144,6 +144,15 @@ config SPI_EP93XX
> This enables using the Cirrus EP93xx SPI controller in master
> mode.
>
> +config SPI_FALCON
> + tristate "Falcon SPI controller support"
> + depends on SOC_FALCON
> + help
> + The external bus unit (EBU) found on the FALC-ON SoC has SPI
> + emulation that is designed for serial flash access. This driver
> + has only been tested with m25p80 type chips. The hardware has no
> + support for other types of spi peripherals.
Maybe also caps this "spi"? ;)
> +
> config SPI_GPIO
> tristate "GPIO-based bitbanging SPI Master"
> depends on GENERIC_GPIO
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index 9d75d21..b5cbab2 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_SPI_DW_MMIO) += spi-dw-mmio.o
> obj-$(CONFIG_SPI_DW_PCI) += spi-dw-midpci.o
> spi-dw-midpci-objs := spi-dw-pci.o spi-dw-mid.o
> obj-$(CONFIG_SPI_EP93XX) += spi-ep93xx.o
> +obj-$(CONFIG_SPI_FALCON) += spi-falcon.o
> obj-$(CONFIG_SPI_FSL_LIB) += spi-fsl-lib.o
> obj-$(CONFIG_SPI_FSL_ESPI) += spi-fsl-espi.o
> obj-$(CONFIG_SPI_FSL_SPI) += spi-fsl-spi.o
> diff --git a/drivers/spi/spi-falcon.c b/drivers/spi/spi-falcon.c
> new file mode 100644
> index 0000000..3be285e
> --- /dev/null
> +++ b/drivers/spi/spi-falcon.c
> @@ -0,0 +1,473 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published
> + * by the Free Software Foundation.
> + *
> + * Copyright (C) 2012 Thomas Langer <thomas.langer@xxxxxxxxxx>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/spi/spi.h>
> +#include <linux/delay.h>
> +#include <linux/workqueue.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +
> +#include <lantiq_soc.h>
> +
> +#define DRV_NAME "sflash-falcon"
> +
> +#define FALCON_SPI_XFER_BEGIN (1 << 0)
> +#define FALCON_SPI_XFER_END (1 << 1)
> +
> +/* Bus Read Configuration Register0 */
> +#define BUSRCON0 0x00000010
> +/* Bus Write Configuration Register0 */
> +#define BUSWCON0 0x00000018
> +/* Serial Flash Configuration Register */
> +#define SFCON 0x00000080
> +/* Serial Flash Time Register */
> +#define SFTIME 0x00000084
> +/* Serial Flash Status Register */
> +#define SFSTAT 0x00000088
> +/* Serial Flash Command Register */
> +#define SFCMD 0x0000008C
> +/* Serial Flash Address Register */
> +#define SFADDR 0x00000090
> +/* Serial Flash Data Register */
> +#define SFDATA 0x00000094
> +/* Serial Flash I/O Control Register */
> +#define SFIO 0x00000098
> +/* EBU Clock Control Register */
> +#define EBUCC 0x000000C4
> +
> +/* Dummy Phase Length */
> +#define SFCMD_DUMLEN_OFFSET 16
> +#define SFCMD_DUMLEN_MASK 0x000F0000
> +/* Chip Select */
> +#define SFCMD_CS_OFFSET 24
> +#define SFCMD_CS_MASK 0x07000000
> +/* field offset */
> +#define SFCMD_ALEN_OFFSET 20
> +#define SFCMD_ALEN_MASK 0x00700000
> +/* SCK Rise-edge Position */
> +#define SFTIME_SCKR_POS_OFFSET 8
> +#define SFTIME_SCKR_POS_MASK 0x00000F00
> +/* SCK Period */
> +#define SFTIME_SCK_PER_OFFSET 0
> +#define SFTIME_SCK_PER_MASK 0x0000000F
> +/* SCK Fall-edge Position */
> +#define SFTIME_SCKF_POS_OFFSET 12
> +#define SFTIME_SCKF_POS_MASK 0x0000F000
> +/* Device Size */
> +#define SFCON_DEV_SIZE_A23_0 0x03000000
> +#define SFCON_DEV_SIZE_MASK 0x0F000000
> +/* Read Data Position */
> +#define SFTIME_RD_POS_MASK 0x000F0000
> +/* Data Output */
> +#define SFIO_UNUSED_WD_MASK 0x0000000F
> +/* Command Opcode mask */
> +#define SFCMD_OPC_MASK 0x000000FF
> +/* dlen bytes of data to write */
> +#define SFCMD_DIR_WRITE 0x00000100
> +/* Data Length offset */
> +#define SFCMD_DLEN_OFFSET 9
> +/* Command Error */
> +#define SFSTAT_CMD_ERR 0x20000000
> +/* Access Command Pending */
> +#define SFSTAT_CMD_PEND 0x00400000
> +/* Frequency set to 100MHz. */
> +#define EBUCC_EBUDIV_SELF100 0x00000001
> +/* Serial Flash */
> +#define BUSRCON0_AGEN_SERIAL_FLASH 0xF0000000
> +/* 8-bit multiplexed */
> +#define BUSRCON0_PORTW_8_BIT_MUX 0x00000000
> +/* Serial Flash */
> +#define BUSWCON0_AGEN_SERIAL_FLASH 0xF0000000
> +/* Chip Select after opcode */
> +#define SFCMD_KEEP_CS_KEEP_SELECTED 0x00008000
> +
> +#define CLOCK_100M 100000000
> +
> +struct falcon_sflash {
> + u32 sfcmd; /* for caching of opcode, direction, ... */
> + struct spi_master *master;
> +};
> +
> +int falcon_sflash_xfer(struct spi_device *spi, struct spi_transfer *t,
> + unsigned long flags)
> +{
> + struct device *dev = &spi->dev;
> + struct falcon_sflash *priv = spi_master_get_devdata(spi->master);
> + const u8 *txp = t->tx_buf;
> + u8 *rxp = t->rx_buf;
> + unsigned int bytelen = ((8 * t->len + 7) / 8);
> + unsigned int len, alen, dumlen;
> + u32 val;
> + enum {
> + state_init,
> + state_command_prepare,
> + state_write,
> + state_read,
> + state_disable_cs,
> + state_end
> + } state = state_init;
> +
> + do {
> + switch (state) {
> + case state_init: /* detect phase of upper layer sequence */
> + {
> + /* initial write ? */
> + if (flags & FALCON_SPI_XFER_BEGIN) {
> + if (!txp) {
> + dev_err(dev,
> + "BEGIN without tx data!\n");
> + return -ENODATA;
> + }
> + /*
> + * Prepare the parts of the sfcmd register,
> + * which should not change during a sequence!
> + * Only exception are the length fields,
> + * especially alen and dumlen.
> + */
> +
> + priv->sfcmd = ((spi->chip_select
> + << SFCMD_CS_OFFSET)
> + & SFCMD_CS_MASK);
> + priv->sfcmd |= SFCMD_KEEP_CS_KEEP_SELECTED;
> + priv->sfcmd |= *txp;
> + txp++;
> + bytelen--;
> + if (bytelen) {
> + /*
> + * more data:
> + * maybe address and/or dummy
> + */
> + state = state_command_prepare;
> + break;
> + } else {
> + dev_dbg(dev, "write cmd %02X\n",
> + priv->sfcmd & SFCMD_OPC_MASK);
> + }
> + }
> + /* continued write ? */
> + if (txp && bytelen) {
> + state = state_write;
> + break;
> + }
> + /* read data? */
> + if (rxp && bytelen) {
> + state = state_read;
> + break;
> + }
> + /* end of sequence? */
> + if (flags & FALCON_SPI_XFER_END)
> + state = state_disable_cs;
> + else
> + state = state_end;
> + break;
> + }
> + /* collect tx data for address and dummy phase */
> + case state_command_prepare:
> + {
> + /* txp is valid, already checked */
> + val = 0;
> + alen = 0;
> + dumlen = 0;
> + while (bytelen > 0) {
> + if (alen < 3) {
> + val = (val << 8) | (*txp++);
> + alen++;
> + } else if ((dumlen < 15) && (*txp == 0)) {
> + /*
> + * assume dummy bytes are set to 0
> + * from upper layer
> + */
> + dumlen++;
> + txp++;
> + } else
> + break;
missing braces around the break.
> + bytelen--;
> + }
> + priv->sfcmd &= ~(SFCMD_ALEN_MASK | SFCMD_DUMLEN_MASK);
> + priv->sfcmd |= (alen << SFCMD_ALEN_OFFSET) |
> + (dumlen << SFCMD_DUMLEN_OFFSET);
> + if (alen > 0)
> + ltq_ebu_w32(val, SFADDR);
> +
> + dev_dbg(dev, "wr %02X, alen=%d (addr=%06X) dlen=%d\n",
> + priv->sfcmd & SFCMD_OPC_MASK,
> + alen, val, dumlen);
> +
> + if (bytelen > 0) {
> + /* continue with write */
> + state = state_write;
> + } else if (flags & FALCON_SPI_XFER_END) {
> + /* end of sequence? */
> + state = state_disable_cs;
> + } else {
> + /*
> + * go to end and expect another
> + * call (read or write)
> + */
> + state = state_end;
> + }
> + break;
> + }
> + case state_write:
> + {
> + /* txp still valid */
> + priv->sfcmd |= SFCMD_DIR_WRITE;
> + len = 0;
> + val = 0;
> + do {
> + if (bytelen--)
> + val |= (*txp++) << (8 * len++);
> + if ((flags & FALCON_SPI_XFER_END)
> + && (bytelen == 0)) {
> + priv->sfcmd &=
> + ~SFCMD_KEEP_CS_KEEP_SELECTED;
> + }
> + if ((len == 4) || (bytelen == 0)) {
> + ltq_ebu_w32(val, SFDATA);
> + ltq_ebu_w32(priv->sfcmd
> + | (len<<SFCMD_DLEN_OFFSET),
> + SFCMD);
> + len = 0;
> + val = 0;
> + priv->sfcmd &= ~(SFCMD_ALEN_MASK
> + | SFCMD_DUMLEN_MASK);
> + }
> + } while (bytelen);
> + state = state_end;
> + break;
> + }
> + case state_read:
> + {
> + /* read data */
> + priv->sfcmd &= ~SFCMD_DIR_WRITE;
> + do {
> + if ((flags & FALCON_SPI_XFER_END)
> + && (bytelen <= 4)) {
> + priv->sfcmd &=
> + ~SFCMD_KEEP_CS_KEEP_SELECTED;
> + }
> + len = (bytelen > 4) ? 4 : bytelen;
> + bytelen -= len;
> + ltq_ebu_w32(priv->sfcmd
> + |(len<<SFCMD_DLEN_OFFSET), SFCMD);
missing space between | and (.
> + priv->sfcmd &= ~(SFCMD_ALEN_MASK
> + | SFCMD_DUMLEN_MASK);
> + do {
> + val = ltq_ebu_r32(SFSTAT);
> + if (val & SFSTAT_CMD_ERR) {
> + /* reset error status */
> + dev_err(dev, "SFSTAT: CMD_ERR");
> + dev_err(dev, " (%x)\n", val);
> + ltq_ebu_w32(SFSTAT_CMD_ERR,
> + SFSTAT);
> + return -EBADE;
> + }
> + } while (val & SFSTAT_CMD_PEND);
> + val = ltq_ebu_r32(SFDATA);
> + do {
> + *rxp = (val & 0xFF);
> + rxp++;
> + val >>= 8;
> + len--;
> + } while (len);
> + } while (bytelen);
> + state = state_end;
> + break;
> + }
> + case state_disable_cs:
> + {
> + priv->sfcmd &= ~SFCMD_KEEP_CS_KEEP_SELECTED;
> + ltq_ebu_w32(priv->sfcmd | (0 << SFCMD_DLEN_OFFSET),
> + SFCMD);
> + val = ltq_ebu_r32(SFSTAT);
> + if (val & SFSTAT_CMD_ERR) {
> + /* reset error status */
> + dev_err(dev, "SFSTAT: CMD_ERR (%x)\n", val);
> + ltq_ebu_w32(SFSTAT_CMD_ERR, SFSTAT);
> + return -EBADE;
> + }
> + state = state_end;
> + break;
> + }
> + case state_end:
> + break;
> + }
> + } while (state != state_end);
> +
> + return 0;
> +}
> +
> +static int falcon_sflash_setup(struct spi_device *spi)
> +{
> + const u32 ebuclk = CLOCK_100M;
> + unsigned int i;
> + unsigned long flags;
> +
> + if (spi->chip_select > 0)
> + return -ENODEV;
> +
> + spin_lock_irqsave(&ebu_lock, flags);
> +
> + if (ebuclk < spi->max_speed_hz) {
Maybe <= ? setting the EBU to 100 Mhz if exactly 100 Mhz is requested
sounds reasonable to me :)
> + /* set EBU clock to 100 MHz */
> + ltq_sys1_w32_mask(0, EBUCC_EBUDIV_SELF100, EBUCC);
> + i = 1; /* divider */
> + } else {
> + /* set EBU clock to 50 MHz */
> + ltq_sys1_w32_mask(EBUCC_EBUDIV_SELF100, 0, EBUCC);
Don't you have to set ebuclk also to CLOCK_50M? Else ..
> +
> + /* search for suitable divider */
> + for (i = 1; i < 7; i++) {
> + if (ebuclk / i <= spi->max_speed_hz)
> + break;
it seems you will select half the intended speed.
> + }
> + }
> +
> + /* setup period of serial clock */
> + ltq_ebu_w32_mask(SFTIME_SCKF_POS_MASK
> + | SFTIME_SCKR_POS_MASK
> + | SFTIME_SCK_PER_MASK,
> + (i << SFTIME_SCKR_POS_OFFSET)
> + | (i << (SFTIME_SCK_PER_OFFSET + 1)),
> + SFTIME);
> +
> + /*
> + * set some bits of unused_wd, to not trigger HOLD/WP
> + * signals on non QUAD flashes
> + */
> + ltq_ebu_w32((SFIO_UNUSED_WD_MASK & (0x8 | 0x4)), SFIO);
> +
> + ltq_ebu_w32(BUSRCON0_AGEN_SERIAL_FLASH | BUSRCON0_PORTW_8_BIT_MUX,
> + BUSRCON0);
> + ltq_ebu_w32(BUSWCON0_AGEN_SERIAL_FLASH, BUSWCON0);
> + /* set address wrap around to maximum for 24-bit addresses */
> + ltq_ebu_w32_mask(SFCON_DEV_SIZE_MASK, SFCON_DEV_SIZE_A23_0, SFCON);
> +
> + spin_unlock_irqrestore(&ebu_lock, flags);
> +
> + return 0;
> +}
> +
> +static int falcon_sflash_prepare_xfer(struct spi_master *master)
> +{
> + return 0;
> +}
> +
> +static int falcon_sflash_unprepare_xfer(struct spi_master *master)
> +{
> + return 0;
> +}
There was a patch accepted just a few days ago dropping the
requirement for (un)prepare_transfer being populated :)
> (snip)
Jonas
