From 97ffc04a7528abe1d84c069d99afb19704d50224 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Tue, 13 May 2014 00:18:58 +0200 Subject: [PATCH] spi: add rb4xx SPI driver --- drivers/spi/Kconfig | 6 + drivers/spi/Makefile | 1 + drivers/spi/spi-rb4xx.c | 507 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 514 insertions(+) create mode 100644 drivers/spi/spi-rb4xx.c diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 581ee2a..721f3a7 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -381,6 +381,12 @@ config SPI_RSPI help SPI driver for Renesas RSPI and QSPI blocks. +config SPI_RB4XX + tristate "Mikrotik RB4XX SPI master" + depends on SPI_MASTER && ATH79_MACH_RB4XX + help + SPI controller driver for the Mikrotik RB4xx series boards. + config SPI_S3C24XX tristate "Samsung S3C24XX series SPI" depends on ARCH_S3C24XX diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 95af48d..e738c7a 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -59,6 +59,7 @@ spi-pxa2xx-platform-$(CONFIG_SPI_PXA2XX_PXADMA) += spi-pxa2xx-pxadma.o spi-pxa2xx-platform-$(CONFIG_SPI_PXA2XX_DMA) += spi-pxa2xx-dma.o obj-$(CONFIG_SPI_PXA2XX) += spi-pxa2xx-platform.o obj-$(CONFIG_SPI_PXA2XX_PCI) += spi-pxa2xx-pci.o +obj-$(CONFIG_SPI_RB4XX) += spi-rb4xx.o obj-$(CONFIG_SPI_RSPI) += spi-rspi.o obj-$(CONFIG_SPI_S3C24XX) += spi-s3c24xx-hw.o spi-s3c24xx-hw-y := spi-s3c24xx.o diff --git a/drivers/spi/spi-rb4xx.c b/drivers/spi/spi-rb4xx.c new file mode 100644 index 0000000..56260ff --- /dev/null +++ b/drivers/spi/spi-rb4xx.c @@ -0,0 +1,507 @@ +/* + * SPI controller driver for the Mikrotik RB4xx boards + * + * Copyright (C) 2010 Gabor Juhos + * + * This file was based on the patches for Linux 2.6.27.39 published by + * MikroTik for their RouterBoard 4xx series devices. + * + * 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. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#define DRV_NAME "rb4xx-spi" +#define DRV_DESC "Mikrotik RB4xx SPI controller driver" +#define DRV_VERSION "0.1.0" + +#define SPI_CTRL_FASTEST 0x40 +#define SPI_FLASH_HZ 33333334 +#define SPI_CPLD_HZ 33333334 + +#define CPLD_CMD_READ_FAST 0x0b + +#undef RB4XX_SPI_DEBUG + +struct rb4xx_spi { + void __iomem *base; + struct spi_master *master; + + unsigned spi_ctrl_flash; + unsigned spi_ctrl_fread; + + struct clk *ahb_clk; + unsigned long ahb_freq; + + spinlock_t lock; + struct list_head queue; + int busy:1; + int cs_wait; +}; + +static unsigned spi_clk_low = AR71XX_SPI_IOC_CS1; + +#ifdef RB4XX_SPI_DEBUG +static inline void do_spi_delay(void) +{ + ndelay(20000); +} +#else +static inline void do_spi_delay(void) { } +#endif + +static inline void do_spi_init(struct spi_device *spi) +{ + unsigned cs = AR71XX_SPI_IOC_CS0 | AR71XX_SPI_IOC_CS1; + + if (!(spi->mode & SPI_CS_HIGH)) + cs ^= (spi->chip_select == 2) ? AR71XX_SPI_IOC_CS1 : + AR71XX_SPI_IOC_CS0; + + spi_clk_low = cs; +} + +static inline void do_spi_finish(void __iomem *base) +{ + do_spi_delay(); + __raw_writel(AR71XX_SPI_IOC_CS0 | AR71XX_SPI_IOC_CS1, + base + AR71XX_SPI_REG_IOC); +} + +static inline void do_spi_clk(void __iomem *base, int bit) +{ + unsigned bval = spi_clk_low | ((bit & 1) ? AR71XX_SPI_IOC_DO : 0); + + do_spi_delay(); + __raw_writel(bval, base + AR71XX_SPI_REG_IOC); + do_spi_delay(); + __raw_writel(bval | AR71XX_SPI_IOC_CLK, base + AR71XX_SPI_REG_IOC); +} + +static void do_spi_byte(void __iomem *base, unsigned char byte) +{ + do_spi_clk(base, byte >> 7); + do_spi_clk(base, byte >> 6); + do_spi_clk(base, byte >> 5); + do_spi_clk(base, byte >> 4); + do_spi_clk(base, byte >> 3); + do_spi_clk(base, byte >> 2); + do_spi_clk(base, byte >> 1); + do_spi_clk(base, byte); + + pr_debug("spi_byte sent 0x%02x got 0x%02x\n", + (unsigned)byte, + (unsigned char)__raw_readl(base + AR71XX_SPI_REG_RDS)); +} + +static inline void do_spi_clk_fast(void __iomem *base, unsigned bit1, + unsigned bit2) +{ + unsigned bval = (spi_clk_low | + ((bit1 & 1) ? AR71XX_SPI_IOC_DO : 0) | + ((bit2 & 1) ? AR71XX_SPI_IOC_CS2 : 0)); + do_spi_delay(); + __raw_writel(bval, base + AR71XX_SPI_REG_IOC); + do_spi_delay(); + __raw_writel(bval | AR71XX_SPI_IOC_CLK, base + AR71XX_SPI_REG_IOC); +} + +static void do_spi_byte_fast(void __iomem *base, unsigned char byte) +{ + do_spi_clk_fast(base, byte >> 7, byte >> 6); + do_spi_clk_fast(base, byte >> 5, byte >> 4); + do_spi_clk_fast(base, byte >> 3, byte >> 2); + do_spi_clk_fast(base, byte >> 1, byte >> 0); + + pr_debug("spi_byte_fast sent 0x%02x got 0x%02x\n", + (unsigned)byte, + (unsigned char) __raw_readl(base + AR71XX_SPI_REG_RDS)); +} + +static int rb4xx_spi_txrx(void __iomem *base, struct spi_transfer *t) +{ + const unsigned char *rxv_ptr = NULL; + const unsigned char *tx_ptr = t->tx_buf; + unsigned char *rx_ptr = t->rx_buf; + unsigned i; + + pr_debug("spi_txrx len %u tx %u rx %u\n", + t->len, + (t->tx_buf ? 1 : 0), + (t->rx_buf ? 1 : 0)); + + if (t->verify) { + rxv_ptr = tx_ptr; + tx_ptr = NULL; + } + + for (i = 0; i < t->len; ++i) { + unsigned char sdata = tx_ptr ? tx_ptr[i] : 0; + + if (t->fast_write) + do_spi_byte_fast(base, sdata); + else + do_spi_byte(base, sdata); + + if (rx_ptr) { + rx_ptr[i] = __raw_readl(base + AR71XX_SPI_REG_RDS) & 0xff; + } else if (rxv_ptr) { + unsigned char c = __raw_readl(base + AR71XX_SPI_REG_RDS); + if (rxv_ptr[i] != c) + return i; + } + } + + return i; +} + +static int rb4xx_spi_read_fast(struct rb4xx_spi *rbspi, + struct spi_message *m) +{ + struct spi_transfer *t; + const unsigned char *tx_ptr; + unsigned addr; + void __iomem *base = rbspi->base; + + /* check for exactly two transfers */ + if (list_empty(&m->transfers) || + list_is_last(m->transfers.next, &m->transfers) || + !list_is_last(m->transfers.next->next, &m->transfers)) { + return -1; + } + + /* first transfer contains command and address */ + t = list_entry(m->transfers.next, + struct spi_transfer, transfer_list); + + if (t->len != 5 || t->tx_buf == NULL) + return -1; + + tx_ptr = t->tx_buf; + if (tx_ptr[0] != CPLD_CMD_READ_FAST) + return -1; + + addr = tx_ptr[1]; + addr = tx_ptr[2] | (addr << 8); + addr = tx_ptr[3] | (addr << 8); + addr += (unsigned) base; + + m->actual_length += t->len; + + /* second transfer contains data itself */ + t = list_entry(m->transfers.next->next, + struct spi_transfer, transfer_list); + + if (t->tx_buf && !t->verify) + return -1; + + __raw_writel(AR71XX_SPI_FS_GPIO, base + AR71XX_SPI_REG_FS); + __raw_writel(rbspi->spi_ctrl_fread, base + AR71XX_SPI_REG_CTRL); + __raw_writel(0, base + AR71XX_SPI_REG_FS); + + if (t->rx_buf) { + memcpy(t->rx_buf, (const void *)addr, t->len); + } else if (t->tx_buf) { + unsigned char buf[t->len]; + memcpy(buf, (const void *)addr, t->len); + if (memcmp(t->tx_buf, buf, t->len) != 0) + m->status = -EMSGSIZE; + } + m->actual_length += t->len; + + if (rbspi->spi_ctrl_flash != rbspi->spi_ctrl_fread) { + __raw_writel(AR71XX_SPI_FS_GPIO, base + AR71XX_SPI_REG_FS); + __raw_writel(rbspi->spi_ctrl_flash, base + AR71XX_SPI_REG_CTRL); + __raw_writel(0, base + AR71XX_SPI_REG_FS); + } + + return 0; +} + +static int rb4xx_spi_msg(struct rb4xx_spi *rbspi, struct spi_message *m) +{ + struct spi_transfer *t = NULL; + void __iomem *base = rbspi->base; + + m->status = 0; + if (list_empty(&m->transfers)) + return -1; + + if (m->fast_read) + if (rb4xx_spi_read_fast(rbspi, m) == 0) + return -1; + + __raw_writel(AR71XX_SPI_FS_GPIO, base + AR71XX_SPI_REG_FS); + __raw_writel(SPI_CTRL_FASTEST, base + AR71XX_SPI_REG_CTRL); + do_spi_init(m->spi); + + list_for_each_entry(t, &m->transfers, transfer_list) { + int len; + + len = rb4xx_spi_txrx(base, t); + if (len != t->len) { + m->status = -EMSGSIZE; + break; + } + m->actual_length += len; + + if (t->cs_change) { + if (list_is_last(&t->transfer_list, &m->transfers)) { + /* wait for continuation */ + return m->spi->chip_select; + } + do_spi_finish(base); + ndelay(100); + } + } + + do_spi_finish(base); + __raw_writel(rbspi->spi_ctrl_flash, base + AR71XX_SPI_REG_CTRL); + __raw_writel(0, base + AR71XX_SPI_REG_FS); + return -1; +} + +static void rb4xx_spi_process_queue_locked(struct rb4xx_spi *rbspi, + unsigned long *flags) +{ + int cs = rbspi->cs_wait; + + rbspi->busy = 1; + while (!list_empty(&rbspi->queue)) { + struct spi_message *m; + + list_for_each_entry(m, &rbspi->queue, queue) + if (cs < 0 || cs == m->spi->chip_select) + break; + + if (&m->queue == &rbspi->queue) + break; + + list_del_init(&m->queue); + spin_unlock_irqrestore(&rbspi->lock, *flags); + + cs = rb4xx_spi_msg(rbspi, m); + m->complete(m->context); + + spin_lock_irqsave(&rbspi->lock, *flags); + } + + rbspi->cs_wait = cs; + rbspi->busy = 0; + + if (cs >= 0) { + /* TODO: add timer to unlock cs after 1s inactivity */ + } +} + +static int rb4xx_spi_transfer(struct spi_device *spi, + struct spi_message *m) +{ + struct rb4xx_spi *rbspi = spi_master_get_devdata(spi->master); + unsigned long flags; + + m->actual_length = 0; + m->status = -EINPROGRESS; + + spin_lock_irqsave(&rbspi->lock, flags); + list_add_tail(&m->queue, &rbspi->queue); + if (rbspi->busy || + (rbspi->cs_wait >= 0 && rbspi->cs_wait != m->spi->chip_select)) { + /* job will be done later */ + spin_unlock_irqrestore(&rbspi->lock, flags); + return 0; + } + + /* process job in current context */ + rb4xx_spi_process_queue_locked(rbspi, &flags); + spin_unlock_irqrestore(&rbspi->lock, flags); + + return 0; +} + +static int rb4xx_spi_setup(struct spi_device *spi) +{ + struct rb4xx_spi *rbspi = spi_master_get_devdata(spi->master); + unsigned long flags; + + if (spi->mode & ~(SPI_CS_HIGH)) { + dev_err(&spi->dev, "mode %x not supported\n", + (unsigned) spi->mode); + return -EINVAL; + } + + if (spi->bits_per_word != 8 && spi->bits_per_word != 0) { + dev_err(&spi->dev, "bits_per_word %u not supported\n", + (unsigned) spi->bits_per_word); + return -EINVAL; + } + + spin_lock_irqsave(&rbspi->lock, flags); + if (rbspi->cs_wait == spi->chip_select && !rbspi->busy) { + rbspi->cs_wait = -1; + rb4xx_spi_process_queue_locked(rbspi, &flags); + } + spin_unlock_irqrestore(&rbspi->lock, flags); + + return 0; +} + +static unsigned get_spi_ctrl(struct rb4xx_spi *rbspi, unsigned hz_max, + const char *name) +{ + unsigned div; + + div = (rbspi->ahb_freq - 1) / (2 * hz_max); + + /* + * CPU has a bug at (div == 0) - first bit read is random + */ + if (div == 0) + ++div; + + if (name) { + unsigned ahb_khz = (rbspi->ahb_freq + 500) / 1000; + unsigned div_real = 2 * (div + 1); + pr_debug("rb4xx: %s SPI clock %u kHz (AHB %u kHz / %u)\n", + name, + ahb_khz / div_real, + ahb_khz, div_real); + } + + return SPI_CTRL_FASTEST + div; +} + +static int rb4xx_spi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct rb4xx_spi *rbspi; + struct resource *r; + int err = 0; + + master = spi_alloc_master(&pdev->dev, sizeof(*rbspi)); + if (master == NULL) { + dev_err(&pdev->dev, "no memory for spi_master\n"); + err = -ENOMEM; + goto err_out; + } + + master->bus_num = 0; + master->num_chipselect = 3; + master->setup = rb4xx_spi_setup; + master->transfer = rb4xx_spi_transfer; + + rbspi = spi_master_get_devdata(master); + + rbspi->ahb_clk = clk_get(&pdev->dev, "ahb"); + if (IS_ERR(rbspi->ahb_clk)) { + err = PTR_ERR(rbspi->ahb_clk); + goto err_put_master; + } + + err = clk_enable(rbspi->ahb_clk); + if (err) + goto err_clk_put; + + rbspi->ahb_freq = clk_get_rate(rbspi->ahb_clk); + if (!rbspi->ahb_freq) { + err = -EINVAL; + goto err_clk_disable; + } + + platform_set_drvdata(pdev, rbspi); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) { + err = -ENOENT; + goto err_clk_disable; + } + + rbspi->base = ioremap(r->start, r->end - r->start + 1); + if (!rbspi->base) { + err = -ENXIO; + goto err_clk_disable; + } + + rbspi->master = master; + rbspi->spi_ctrl_flash = get_spi_ctrl(rbspi, SPI_FLASH_HZ, "FLASH"); + rbspi->spi_ctrl_fread = get_spi_ctrl(rbspi, SPI_CPLD_HZ, "CPLD"); + rbspi->cs_wait = -1; + + spin_lock_init(&rbspi->lock); + INIT_LIST_HEAD(&rbspi->queue); + + err = spi_register_master(master); + if (err) { + dev_err(&pdev->dev, "failed to register SPI master\n"); + goto err_iounmap; + } + + return 0; + +err_iounmap: + iounmap(rbspi->base); +err_clk_disable: + clk_disable(rbspi->ahb_clk); +err_clk_put: + clk_put(rbspi->ahb_clk); +err_put_master: + platform_set_drvdata(pdev, NULL); + spi_master_put(master); +err_out: + return err; +} + +static int rb4xx_spi_remove(struct platform_device *pdev) +{ + struct rb4xx_spi *rbspi = platform_get_drvdata(pdev); + + iounmap(rbspi->base); + clk_disable(rbspi->ahb_clk); + clk_put(rbspi->ahb_clk); + platform_set_drvdata(pdev, NULL); + spi_master_put(rbspi->master); + + return 0; +} + +static struct platform_driver rb4xx_spi_drv = { + .probe = rb4xx_spi_probe, + .remove = rb4xx_spi_remove, + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + }, +}; + +static int __init rb4xx_spi_init(void) +{ + return platform_driver_register(&rb4xx_spi_drv); +} +subsys_initcall(rb4xx_spi_init); + +static void __exit rb4xx_spi_exit(void) +{ + platform_driver_unregister(&rb4xx_spi_drv); +} + +module_exit(rb4xx_spi_exit); + +MODULE_DESCRIPTION(DRV_DESC); +MODULE_VERSION(DRV_VERSION); +MODULE_AUTHOR("Gabor Juhos "); +MODULE_LICENSE("GPL v2"); -- 1.8.5.3