/* * 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 *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)); for (i = 0; i < t->len; ++i) { unsigned char sdata = tx_ptr ? tx_ptr[i] : 0; if (t->tx_nbits == SPI_NBITS_DUAL) 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; } return i; } 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; __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 | SPI_TX_DUAL)) { 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->mode_bits = SPI_TX_DUAL; 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_prepare_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");