diff options
author | Rafał Miłecki <zajec5@gmail.com> | 2014-08-17 16:33:38 (GMT) |
---|---|---|
committer | Mark Brown <broonie@linaro.org> | 2014-08-19 16:30:55 (GMT) |
commit | 0fc6a323e19173fc89e17940bb1e19447aa0224e (patch) | |
tree | e02ffb5dbea410af6f6ba489dad3d10b7e441397 /drivers/spi/spi-bcm53xx.c | |
parent | 7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9 (diff) | |
download | linux-0fc6a323e19173fc89e17940bb1e19447aa0224e.tar.xz |
spi: bcm53xx: driver for SPI controller on Broadcom bcma SoC
Broadcom 53xx ARM SoCs use bcma bus that contains various cores (AKA
devices). If board has a serial flash, it's connected over SPI and the
bcma bus includes a SPI controller. Example log from such a board:
bus0: Found chip with id 53010, rev 0x00 and package 0x02
(...)
bus0: Core 18 found: SPI flash controller (manuf 0x4BF, id 0x50A, rev 0x01, class 0x0)
This patch adds a bcma driver for SPI core, it registers SPI master
controller and "bcm53xxspiflash" SPI device.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Diffstat (limited to 'drivers/spi/spi-bcm53xx.c')
-rw-r--r-- | drivers/spi/spi-bcm53xx.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/spi/spi-bcm53xx.c b/drivers/spi/spi-bcm53xx.c new file mode 100644 index 0000000..48f13df --- /dev/null +++ b/drivers/spi/spi-bcm53xx.c @@ -0,0 +1,295 @@ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/delay.h> +#include <linux/bcma/bcma.h> +#include <linux/spi/spi.h> + +#include "spi-bcm53xx.h" + +#define BCM53XXSPI_MAX_SPI_BAUD 13500000 /* 216 MHz? */ + +/* The longest observed required wait was 19 ms */ +#define BCM53XXSPI_SPE_TIMEOUT_MS 80 + +struct bcm53xxspi { + struct bcma_device *core; + struct spi_master *master; + + size_t read_offset; +}; + +static inline u32 bcm53xxspi_read(struct bcm53xxspi *b53spi, u16 offset) +{ + return bcma_read32(b53spi->core, offset); +} + +static inline void bcm53xxspi_write(struct bcm53xxspi *b53spi, u16 offset, + u32 value) +{ + bcma_write32(b53spi->core, offset, value); +} + +static inline unsigned int bcm53xxspi_calc_timeout(size_t len) +{ + /* Do some magic calculation based on length and buad. Add 10% and 1. */ + return (len * 9000 / BCM53XXSPI_MAX_SPI_BAUD * 110 / 100) + 1; +} + +static int bcm53xxspi_wait(struct bcm53xxspi *b53spi, unsigned int timeout_ms) +{ + unsigned long deadline; + u32 tmp; + + /* SPE bit has to be 0 before we read MSPI STATUS */ + deadline = jiffies + BCM53XXSPI_SPE_TIMEOUT_MS * HZ / 1000; + do { + tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2); + if (!(tmp & B53SPI_MSPI_SPCR2_SPE)) + break; + udelay(5); + } while (!time_after_eq(jiffies, deadline)); + + if (tmp & B53SPI_MSPI_SPCR2_SPE) + goto spi_timeout; + + /* Check status */ + deadline = jiffies + timeout_ms * HZ / 1000; + do { + tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_MSPI_STATUS); + if (tmp & B53SPI_MSPI_MSPI_STATUS_SPIF) { + bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0); + return 0; + } + + cpu_relax(); + udelay(100); + } while (!time_after_eq(jiffies, deadline)); + +spi_timeout: + bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0); + + pr_err("Timeout waiting for SPI to be ready!\n"); + + return -EBUSY; +} + +static void bcm53xxspi_buf_write(struct bcm53xxspi *b53spi, u8 *w_buf, + size_t len, bool cont) +{ + u32 tmp; + int i; + + for (i = 0; i < len; i++) { + /* Transmit Register File MSB */ + bcm53xxspi_write(b53spi, B53SPI_MSPI_TXRAM + 4 * (i * 2), + (unsigned int)w_buf[i]); + } + + for (i = 0; i < len; i++) { + tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL | + B53SPI_CDRAM_PCS_DSCK; + if (!cont && i == len - 1) + tmp &= ~B53SPI_CDRAM_CONT; + tmp &= ~0x1; + /* Command Register File */ + bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp); + } + + /* Set queue pointers */ + bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0); + bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP, len - 1); + + if (cont) + bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1); + + /* Start SPI transfer */ + tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2); + tmp |= B53SPI_MSPI_SPCR2_SPE; + if (cont) + tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD; + bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp); + + /* Wait for SPI to finish */ + bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len)); + + if (!cont) + bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0); + + b53spi->read_offset = len; +} + +static void bcm53xxspi_buf_read(struct bcm53xxspi *b53spi, u8 *r_buf, + size_t len, bool cont) +{ + u32 tmp; + int i; + + for (i = 0; i < b53spi->read_offset + len; i++) { + tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL | + B53SPI_CDRAM_PCS_DSCK; + if (!cont && i == b53spi->read_offset + len - 1) + tmp &= ~B53SPI_CDRAM_CONT; + tmp &= ~0x1; + /* Command Register File */ + bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp); + } + + /* Set queue pointers */ + bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0); + bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP, + b53spi->read_offset + len - 1); + + if (cont) + bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1); + + /* Start SPI transfer */ + tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2); + tmp |= B53SPI_MSPI_SPCR2_SPE; + if (cont) + tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD; + bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp); + + /* Wait for SPI to finish */ + bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len)); + + if (!cont) + bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0); + + for (i = 0; i < len; ++i) { + int offset = b53spi->read_offset + i; + + /* Data stored in the transmit register file LSB */ + r_buf[i] = (u8)bcm53xxspi_read(b53spi, B53SPI_MSPI_RXRAM + 4 * (1 + offset * 2)); + } + + b53spi->read_offset = 0; +} + +static int bcm53xxspi_transfer_one(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *t) +{ + struct bcm53xxspi *b53spi = spi_master_get_devdata(master); + u8 *buf; + size_t left; + + if (t->tx_buf) { + buf = (u8 *)t->tx_buf; + left = t->len; + while (left) { + size_t to_write = min_t(size_t, 16, left); + bool cont = left - to_write > 0; + + bcm53xxspi_buf_write(b53spi, buf, to_write, cont); + left -= to_write; + buf += to_write; + } + } + + if (t->rx_buf) { + buf = (u8 *)t->rx_buf; + left = t->len; + while (left) { + size_t to_read = min_t(size_t, 16 - b53spi->read_offset, + left); + bool cont = left - to_read > 0; + + bcm53xxspi_buf_read(b53spi, buf, to_read, cont); + left -= to_read; + buf += to_read; + } + } + + return 0; +} + +/************************************************** + * BCMA + **************************************************/ + +struct spi_board_info bcm53xx_info = { + .modalias = "bcm53xxspiflash", +}; + +static const struct bcma_device_id bcm53xxspi_bcma_tbl[] = { + BCMA_CORE(BCMA_MANUF_BCM, BCMA_CORE_NS_QSPI, BCMA_ANY_REV, BCMA_ANY_CLASS), + BCMA_CORETABLE_END +}; +MODULE_DEVICE_TABLE(bcma, bcm53xxspi_bcma_tbl); + +static int bcm53xxspi_bcma_probe(struct bcma_device *core) +{ + struct bcm53xxspi *b53spi; + struct spi_master *master; + int err; + + if (core->bus->drv_cc.core->id.rev != 42) { + pr_err("SPI on SoC with unsupported ChipCommon rev\n"); + return -ENOTSUPP; + } + + master = spi_alloc_master(&core->dev, sizeof(*b53spi)); + if (!master) + return -ENOMEM; + + b53spi = spi_master_get_devdata(master); + b53spi->master = master; + b53spi->core = core; + + master->transfer_one = bcm53xxspi_transfer_one; + + bcma_set_drvdata(core, b53spi); + + err = devm_spi_register_master(&core->dev, master); + if (err) { + spi_master_put(master); + bcma_set_drvdata(core, NULL); + goto out; + } + + /* Broadcom SoCs (at least with the CC rev 42) use SPI for flash only */ + spi_new_device(master, &bcm53xx_info); + +out: + return err; +} + +static void bcm53xxspi_bcma_remove(struct bcma_device *core) +{ + struct bcm53xxspi *b53spi = bcma_get_drvdata(core); + + spi_unregister_master(b53spi->master); +} + +static struct bcma_driver bcm53xxspi_bcma_driver = { + .name = KBUILD_MODNAME, + .id_table = bcm53xxspi_bcma_tbl, + .probe = bcm53xxspi_bcma_probe, + .remove = bcm53xxspi_bcma_remove, +}; + +/************************************************** + * Init & exit + **************************************************/ + +static int __init bcm53xxspi_module_init(void) +{ + int err = 0; + + err = bcma_driver_register(&bcm53xxspi_bcma_driver); + if (err) + pr_err("Failed to register bcma driver: %d\n", err); + + return err; +} + +static void __exit bcm53xxspi_module_exit(void) +{ + bcma_driver_unregister(&bcm53xxspi_bcma_driver); +} + +module_init(bcm53xxspi_module_init); +module_exit(bcm53xxspi_module_exit); |