diff options
Diffstat (limited to 'kernel/drivers/spi/spi-falcon.c')
| -rw-r--r-- | kernel/drivers/spi/spi-falcon.c | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/kernel/drivers/spi/spi-falcon.c b/kernel/drivers/spi/spi-falcon.c new file mode 100644 index 000000000..286b2c81f --- /dev/null +++ b/kernel/drivers/spi/spi-falcon.c @@ -0,0 +1,439 @@ +/* + * 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@lantiq.com> + */ + +#include <linux/module.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> +#include <linux/delay.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 +#define CLOCK_50M 50000000 + +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; + } + 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); + 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) +{ + unsigned int i; + unsigned long flags; + + spin_lock_irqsave(&ebu_lock, flags); + + if (spi->max_speed_hz >= CLOCK_100M) { + /* 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); + + /* search for suitable divider */ + for (i = 1; i < 7; i++) { + if (CLOCK_50M / i <= spi->max_speed_hz) + break; + } + } + + /* 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_xfer_one(struct spi_master *master, + struct spi_message *m) +{ + struct falcon_sflash *priv = spi_master_get_devdata(master); + struct spi_transfer *t; + unsigned long spi_flags; + unsigned long flags; + int ret = 0; + + priv->sfcmd = 0; + m->actual_length = 0; + + spi_flags = FALCON_SPI_XFER_BEGIN; + list_for_each_entry(t, &m->transfers, transfer_list) { + if (list_is_last(&t->transfer_list, &m->transfers)) + spi_flags |= FALCON_SPI_XFER_END; + + spin_lock_irqsave(&ebu_lock, flags); + ret = falcon_sflash_xfer(m->spi, t, spi_flags); + spin_unlock_irqrestore(&ebu_lock, flags); + + if (ret) + break; + + m->actual_length += t->len; + + WARN_ON(t->delay_usecs || t->cs_change); + spi_flags = 0; + } + + m->status = ret; + spi_finalize_current_message(master); + + return 0; +} + +static int falcon_sflash_probe(struct platform_device *pdev) +{ + struct falcon_sflash *priv; + struct spi_master *master; + int ret; + + if (ltq_boot_select() != BS_SPI) { + dev_err(&pdev->dev, "invalid bootstrap options\n"); + return -ENODEV; + } + + master = spi_alloc_master(&pdev->dev, sizeof(*priv)); + if (!master) + return -ENOMEM; + + priv = spi_master_get_devdata(master); + priv->master = master; + + master->mode_bits = SPI_MODE_3; + master->flags = SPI_MASTER_HALF_DUPLEX; + master->setup = falcon_sflash_setup; + master->transfer_one_message = falcon_sflash_xfer_one; + master->dev.of_node = pdev->dev.of_node; + + ret = devm_spi_register_master(&pdev->dev, master); + if (ret) + spi_master_put(master); + return ret; +} + +static const struct of_device_id falcon_sflash_match[] = { + { .compatible = "lantiq,sflash-falcon" }, + {}, +}; +MODULE_DEVICE_TABLE(of, falcon_sflash_match); + +static struct platform_driver falcon_sflash_driver = { + .probe = falcon_sflash_probe, + .driver = { + .name = DRV_NAME, + .of_match_table = falcon_sflash_match, + } +}; + +module_platform_driver(falcon_sflash_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Lantiq Falcon SPI/SFLASH controller driver"); |