diff options
Diffstat (limited to 'drivers/spi/spi-tegra.c')
| -rw-r--r-- | drivers/spi/spi-tegra.c | 630 |
1 files changed, 630 insertions, 0 deletions
diff --git a/drivers/spi/spi-tegra.c b/drivers/spi/spi-tegra.c new file mode 100644 index 000000000000..a5a6302dc8e0 --- /dev/null +++ b/drivers/spi/spi-tegra.c @@ -0,0 +1,630 @@ +/* + * Driver for Nvidia TEGRA spi controller. + * + * Copyright (C) 2010 Google, Inc. + * + * Author: + * Erik Gilling <konkers@android.com> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/dma-mapping.h> +#include <linux/dmapool.h> +#include <linux/clk.h> +#include <linux/interrupt.h> +#include <linux/delay.h> + +#include <linux/spi/spi.h> + +#include <mach/dma.h> + +#define SLINK_COMMAND 0x000 +#define SLINK_BIT_LENGTH(x) (((x) & 0x1f) << 0) +#define SLINK_WORD_SIZE(x) (((x) & 0x1f) << 5) +#define SLINK_BOTH_EN (1 << 10) +#define SLINK_CS_SW (1 << 11) +#define SLINK_CS_VALUE (1 << 12) +#define SLINK_CS_POLARITY (1 << 13) +#define SLINK_IDLE_SDA_DRIVE_LOW (0 << 16) +#define SLINK_IDLE_SDA_DRIVE_HIGH (1 << 16) +#define SLINK_IDLE_SDA_PULL_LOW (2 << 16) +#define SLINK_IDLE_SDA_PULL_HIGH (3 << 16) +#define SLINK_IDLE_SDA_MASK (3 << 16) +#define SLINK_CS_POLARITY1 (1 << 20) +#define SLINK_CK_SDA (1 << 21) +#define SLINK_CS_POLARITY2 (1 << 22) +#define SLINK_CS_POLARITY3 (1 << 23) +#define SLINK_IDLE_SCLK_DRIVE_LOW (0 << 24) +#define SLINK_IDLE_SCLK_DRIVE_HIGH (1 << 24) +#define SLINK_IDLE_SCLK_PULL_LOW (2 << 24) +#define SLINK_IDLE_SCLK_PULL_HIGH (3 << 24) +#define SLINK_IDLE_SCLK_MASK (3 << 24) +#define SLINK_M_S (1 << 28) +#define SLINK_WAIT (1 << 29) +#define SLINK_GO (1 << 30) +#define SLINK_ENB (1 << 31) + +#define SLINK_COMMAND2 0x004 +#define SLINK_LSBFE (1 << 0) +#define SLINK_SSOE (1 << 1) +#define SLINK_SPIE (1 << 4) +#define SLINK_BIDIROE (1 << 6) +#define SLINK_MODFEN (1 << 7) +#define SLINK_INT_SIZE(x) (((x) & 0x1f) << 8) +#define SLINK_CS_ACTIVE_BETWEEN (1 << 17) +#define SLINK_SS_EN_CS(x) (((x) & 0x3) << 18) +#define SLINK_SS_SETUP(x) (((x) & 0x3) << 20) +#define SLINK_FIFO_REFILLS_0 (0 << 22) +#define SLINK_FIFO_REFILLS_1 (1 << 22) +#define SLINK_FIFO_REFILLS_2 (2 << 22) +#define SLINK_FIFO_REFILLS_3 (3 << 22) +#define SLINK_FIFO_REFILLS_MASK (3 << 22) +#define SLINK_WAIT_PACK_INT(x) (((x) & 0x7) << 26) +#define SLINK_SPC0 (1 << 29) +#define SLINK_TXEN (1 << 30) +#define SLINK_RXEN (1 << 31) + +#define SLINK_STATUS 0x008 +#define SLINK_COUNT(val) (((val) >> 0) & 0x1f) +#define SLINK_WORD(val) (((val) >> 5) & 0x1f) +#define SLINK_BLK_CNT(val) (((val) >> 0) & 0xffff) +#define SLINK_MODF (1 << 16) +#define SLINK_RX_UNF (1 << 18) +#define SLINK_TX_OVF (1 << 19) +#define SLINK_TX_FULL (1 << 20) +#define SLINK_TX_EMPTY (1 << 21) +#define SLINK_RX_FULL (1 << 22) +#define SLINK_RX_EMPTY (1 << 23) +#define SLINK_TX_UNF (1 << 24) +#define SLINK_RX_OVF (1 << 25) +#define SLINK_TX_FLUSH (1 << 26) +#define SLINK_RX_FLUSH (1 << 27) +#define SLINK_SCLK (1 << 28) +#define SLINK_ERR (1 << 29) +#define SLINK_RDY (1 << 30) +#define SLINK_BSY (1 << 31) + +#define SLINK_MAS_DATA 0x010 +#define SLINK_SLAVE_DATA 0x014 + +#define SLINK_DMA_CTL 0x018 +#define SLINK_DMA_BLOCK_SIZE(x) (((x) & 0xffff) << 0) +#define SLINK_TX_TRIG_1 (0 << 16) +#define SLINK_TX_TRIG_4 (1 << 16) +#define SLINK_TX_TRIG_8 (2 << 16) +#define SLINK_TX_TRIG_16 (3 << 16) +#define SLINK_TX_TRIG_MASK (3 << 16) +#define SLINK_RX_TRIG_1 (0 << 18) +#define SLINK_RX_TRIG_4 (1 << 18) +#define SLINK_RX_TRIG_8 (2 << 18) +#define SLINK_RX_TRIG_16 (3 << 18) +#define SLINK_RX_TRIG_MASK (3 << 18) +#define SLINK_PACKED (1 << 20) +#define SLINK_PACK_SIZE_4 (0 << 21) +#define SLINK_PACK_SIZE_8 (1 << 21) +#define SLINK_PACK_SIZE_16 (2 << 21) +#define SLINK_PACK_SIZE_32 (3 << 21) +#define SLINK_PACK_SIZE_MASK (3 << 21) +#define SLINK_IE_TXC (1 << 26) +#define SLINK_IE_RXC (1 << 27) +#define SLINK_DMA_EN (1 << 31) + +#define SLINK_STATUS2 0x01c +#define SLINK_TX_FIFO_EMPTY_COUNT(val) (((val) & 0x3f) >> 0) +#define SLINK_RX_FIFO_FULL_COUNT(val) (((val) & 0x3f) >> 16) + +#define SLINK_TX_FIFO 0x100 +#define SLINK_RX_FIFO 0x180 + +static const unsigned long spi_tegra_req_sels[] = { + TEGRA_DMA_REQ_SEL_SL2B1, + TEGRA_DMA_REQ_SEL_SL2B2, + TEGRA_DMA_REQ_SEL_SL2B3, + TEGRA_DMA_REQ_SEL_SL2B4, +}; + +#define BB_LEN 32 + +struct spi_tegra_data { + struct spi_master *master; + struct platform_device *pdev; + spinlock_t lock; + + struct clk *clk; + void __iomem *base; + unsigned long phys; + + u32 cur_speed; + + struct list_head queue; + struct spi_transfer *cur; + unsigned cur_pos; + unsigned cur_len; + unsigned cur_bytes_per_word; + + /* The tegra spi controller has a bug which causes the first word + * in PIO transactions to be garbage. Since packed DMA transactions + * require transfers to be 4 byte aligned we need a bounce buffer + * for the generic case. + */ + struct tegra_dma_req rx_dma_req; + struct tegra_dma_channel *rx_dma; + u32 *rx_bb; + dma_addr_t rx_bb_phys; +}; + + +static inline unsigned long spi_tegra_readl(struct spi_tegra_data *tspi, + unsigned long reg) +{ + return readl(tspi->base + reg); +} + +static inline void spi_tegra_writel(struct spi_tegra_data *tspi, + unsigned long val, + unsigned long reg) +{ + writel(val, tspi->base + reg); +} + +static void spi_tegra_go(struct spi_tegra_data *tspi) +{ + unsigned long val; + + wmb(); + + val = spi_tegra_readl(tspi, SLINK_DMA_CTL); + val &= ~SLINK_DMA_BLOCK_SIZE(~0) & ~SLINK_DMA_EN; + val |= SLINK_DMA_BLOCK_SIZE(tspi->rx_dma_req.size / 4 - 1); + spi_tegra_writel(tspi, val, SLINK_DMA_CTL); + + tegra_dma_enqueue_req(tspi->rx_dma, &tspi->rx_dma_req); + + val |= SLINK_DMA_EN; + spi_tegra_writel(tspi, val, SLINK_DMA_CTL); +} + +static unsigned spi_tegra_fill_tx_fifo(struct spi_tegra_data *tspi, + struct spi_transfer *t) +{ + unsigned len = min(t->len - tspi->cur_pos, BB_LEN * + tspi->cur_bytes_per_word); + u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_pos; + int i, j; + unsigned long val; + + val = spi_tegra_readl(tspi, SLINK_COMMAND); + val &= ~SLINK_WORD_SIZE(~0); + val |= SLINK_WORD_SIZE(len / tspi->cur_bytes_per_word - 1); + spi_tegra_writel(tspi, val, SLINK_COMMAND); + + for (i = 0; i < len; i += tspi->cur_bytes_per_word) { + val = 0; + for (j = 0; j < tspi->cur_bytes_per_word; j++) + val |= tx_buf[i + j] << j * 8; + + spi_tegra_writel(tspi, val, SLINK_TX_FIFO); + } + + tspi->rx_dma_req.size = len / tspi->cur_bytes_per_word * 4; + + return len; +} + +static unsigned spi_tegra_drain_rx_fifo(struct spi_tegra_data *tspi, + struct spi_transfer *t) +{ + unsigned len = tspi->cur_len; + u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_pos; + int i, j; + unsigned long val; + + for (i = 0; i < len; i += tspi->cur_bytes_per_word) { + val = tspi->rx_bb[i / tspi->cur_bytes_per_word]; + for (j = 0; j < tspi->cur_bytes_per_word; j++) + rx_buf[i + j] = (val >> (j * 8)) & 0xff; + } + + return len; +} + +static void spi_tegra_start_transfer(struct spi_device *spi, + struct spi_transfer *t) +{ + struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master); + u32 speed; + u8 bits_per_word; + unsigned long val; + + speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz; + bits_per_word = t->bits_per_word ? t->bits_per_word : + spi->bits_per_word; + + tspi->cur_bytes_per_word = (bits_per_word - 1) / 8 + 1; + + if (speed != tspi->cur_speed) + clk_set_rate(tspi->clk, speed); + + if (tspi->cur_speed == 0) + clk_enable(tspi->clk); + + tspi->cur_speed = speed; + + val = spi_tegra_readl(tspi, SLINK_COMMAND2); + val &= ~SLINK_SS_EN_CS(~0) | SLINK_RXEN | SLINK_TXEN; + if (t->rx_buf) + val |= SLINK_RXEN; + if (t->tx_buf) + val |= SLINK_TXEN; + val |= SLINK_SS_EN_CS(spi->chip_select); + val |= SLINK_SPIE; + spi_tegra_writel(tspi, val, SLINK_COMMAND2); + + val = spi_tegra_readl(tspi, SLINK_COMMAND); + val &= ~SLINK_BIT_LENGTH(~0); + val |= SLINK_BIT_LENGTH(bits_per_word - 1); + + /* FIXME: should probably control CS manually so that we can be sure + * it does not go low between transfer and to support delay_usecs + * correctly. + */ + val &= ~SLINK_IDLE_SCLK_MASK & ~SLINK_CK_SDA & ~SLINK_CS_SW; + + if (spi->mode & SPI_CPHA) + val |= SLINK_CK_SDA; + + if (spi->mode & SPI_CPOL) + val |= SLINK_IDLE_SCLK_DRIVE_HIGH; + else + val |= SLINK_IDLE_SCLK_DRIVE_LOW; + + val |= SLINK_M_S; + + spi_tegra_writel(tspi, val, SLINK_COMMAND); + + spi_tegra_writel(tspi, SLINK_RX_FLUSH | SLINK_TX_FLUSH, SLINK_STATUS); + + tspi->cur = t; + tspi->cur_pos = 0; + tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, t); + + spi_tegra_go(tspi); +} + +static void spi_tegra_start_message(struct spi_device *spi, + struct spi_message *m) +{ + struct spi_transfer *t; + + m->actual_length = 0; + m->status = 0; + + t = list_first_entry(&m->transfers, struct spi_transfer, transfer_list); + spi_tegra_start_transfer(spi, t); +} + +static void tegra_spi_rx_dma_complete(struct tegra_dma_req *req) +{ + struct spi_tegra_data *tspi = req->dev; + unsigned long flags; + struct spi_message *m; + struct spi_device *spi; + int timeout = 0; + unsigned long val; + + /* the SPI controller may come back with both the BSY and RDY bits + * set. In this case we need to wait for the BSY bit to clear so + * that we are sure the DMA is finished. 1000 reads was empirically + * determined to be long enough. + */ + while (timeout++ < 1000) { + if (!(spi_tegra_readl(tspi, SLINK_STATUS) & SLINK_BSY)) + break; + } + + spin_lock_irqsave(&tspi->lock, flags); + + val = spi_tegra_readl(tspi, SLINK_STATUS); + val |= SLINK_RDY; + spi_tegra_writel(tspi, val, SLINK_STATUS); + + m = list_first_entry(&tspi->queue, struct spi_message, queue); + + if (timeout >= 1000) + m->status = -EIO; + + spi = m->state; + + tspi->cur_pos += spi_tegra_drain_rx_fifo(tspi, tspi->cur); + m->actual_length += tspi->cur_pos; + + if (tspi->cur_pos < tspi->cur->len) { + tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, tspi->cur); + spi_tegra_go(tspi); + } else if (!list_is_last(&tspi->cur->transfer_list, + &m->transfers)) { + tspi->cur = list_first_entry(&tspi->cur->transfer_list, + struct spi_transfer, + transfer_list); + spi_tegra_start_transfer(spi, tspi->cur); + } else { + list_del(&m->queue); + + m->complete(m->context); + + if (!list_empty(&tspi->queue)) { + m = list_first_entry(&tspi->queue, struct spi_message, + queue); + spi = m->state; + spi_tegra_start_message(spi, m); + } else { + clk_disable(tspi->clk); + tspi->cur_speed = 0; + } + } + + spin_unlock_irqrestore(&tspi->lock, flags); +} + +static int spi_tegra_setup(struct spi_device *spi) +{ + struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master); + unsigned long cs_bit; + unsigned long val; + unsigned long flags; + + dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n", + spi->bits_per_word, + spi->mode & SPI_CPOL ? "" : "~", + spi->mode & SPI_CPHA ? "" : "~", + spi->max_speed_hz); + + + switch (spi->chip_select) { + case 0: + cs_bit = SLINK_CS_POLARITY; + break; + + case 1: + cs_bit = SLINK_CS_POLARITY1; + break; + + case 2: + cs_bit = SLINK_CS_POLARITY2; + break; + + case 4: + cs_bit = SLINK_CS_POLARITY3; + break; + + default: + return -EINVAL; + } + + spin_lock_irqsave(&tspi->lock, flags); + + val = spi_tegra_readl(tspi, SLINK_COMMAND); + if (spi->mode & SPI_CS_HIGH) + val |= cs_bit; + else + val &= ~cs_bit; + spi_tegra_writel(tspi, val, SLINK_COMMAND); + + spin_unlock_irqrestore(&tspi->lock, flags); + + return 0; +} + +static int spi_tegra_transfer(struct spi_device *spi, struct spi_message *m) +{ + struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master); + struct spi_transfer *t; + unsigned long flags; + int was_empty; + + if (list_empty(&m->transfers) || !m->complete) + return -EINVAL; + + list_for_each_entry(t, &m->transfers, transfer_list) { + if (t->bits_per_word < 0 || t->bits_per_word > 32) + return -EINVAL; + + if (t->len == 0) + return -EINVAL; + + if (!t->rx_buf && !t->tx_buf) + return -EINVAL; + } + + m->state = spi; + + spin_lock_irqsave(&tspi->lock, flags); + was_empty = list_empty(&tspi->queue); + list_add_tail(&m->queue, &tspi->queue); + + if (was_empty) + spi_tegra_start_message(spi, m); + + spin_unlock_irqrestore(&tspi->lock, flags); + + return 0; +} + +static int __init spi_tegra_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct spi_tegra_data *tspi; + struct resource *r; + int ret; + + master = spi_alloc_master(&pdev->dev, sizeof *tspi); + if (master == NULL) { + dev_err(&pdev->dev, "master allocation failed\n"); + return -ENOMEM; + } + + /* the spi->mode bits understood by this driver: */ + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; + + master->bus_num = pdev->id; + + master->setup = spi_tegra_setup; + master->transfer = spi_tegra_transfer; + master->num_chipselect = 4; + + dev_set_drvdata(&pdev->dev, master); + tspi = spi_master_get_devdata(master); + tspi->master = master; + tspi->pdev = pdev; + spin_lock_init(&tspi->lock); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) { + ret = -ENODEV; + goto err0; + } + + if (!request_mem_region(r->start, resource_size(r), + dev_name(&pdev->dev))) { + ret = -EBUSY; + goto err0; + } + + tspi->phys = r->start; + tspi->base = ioremap(r->start, resource_size(r)); + if (!tspi->base) { + dev_err(&pdev->dev, "can't ioremap iomem\n"); + ret = -ENOMEM; + goto err1; + } + + tspi->clk = clk_get(&pdev->dev, NULL); + if (IS_ERR(tspi->clk)) { + dev_err(&pdev->dev, "can not get clock\n"); + ret = PTR_ERR(tspi->clk); + goto err2; + } + + INIT_LIST_HEAD(&tspi->queue); + + tspi->rx_dma = tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT); + if (!tspi->rx_dma) { + dev_err(&pdev->dev, "can not allocate rx dma channel\n"); + ret = -ENODEV; + goto err3; + } + + tspi->rx_bb = dma_alloc_coherent(&pdev->dev, sizeof(u32) * BB_LEN, + &tspi->rx_bb_phys, GFP_KERNEL); + if (!tspi->rx_bb) { + dev_err(&pdev->dev, "can not allocate rx bounce buffer\n"); + ret = -ENOMEM; + goto err4; + } + + tspi->rx_dma_req.complete = tegra_spi_rx_dma_complete; + tspi->rx_dma_req.to_memory = 1; + tspi->rx_dma_req.dest_addr = tspi->rx_bb_phys; + tspi->rx_dma_req.dest_bus_width = 32; + tspi->rx_dma_req.source_addr = tspi->phys + SLINK_RX_FIFO; + tspi->rx_dma_req.source_bus_width = 32; + tspi->rx_dma_req.source_wrap = 4; + tspi->rx_dma_req.req_sel = spi_tegra_req_sels[pdev->id]; + tspi->rx_dma_req.dev = tspi; + + master->dev.of_node = pdev->dev.of_node; + ret = spi_register_master(master); + + if (ret < 0) + goto err5; + + return ret; + +err5: + dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN, + tspi->rx_bb, tspi->rx_bb_phys); +err4: + tegra_dma_free_channel(tspi->rx_dma); +err3: + clk_put(tspi->clk); +err2: + iounmap(tspi->base); +err1: + release_mem_region(r->start, resource_size(r)); +err0: + spi_master_put(master); + return ret; +} + +static int __devexit spi_tegra_remove(struct platform_device *pdev) +{ + struct spi_master *master; + struct spi_tegra_data *tspi; + struct resource *r; + + master = dev_get_drvdata(&pdev->dev); + tspi = spi_master_get_devdata(master); + + spi_unregister_master(master); + tegra_dma_free_channel(tspi->rx_dma); + + dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN, + tspi->rx_bb, tspi->rx_bb_phys); + + clk_put(tspi->clk); + iounmap(tspi->base); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + release_mem_region(r->start, resource_size(r)); + + return 0; +} + +MODULE_ALIAS("platform:spi_tegra"); + +#ifdef CONFIG_OF +static struct of_device_id spi_tegra_of_match_table[] __devinitdata = { + { .compatible = "nvidia,tegra20-spi", }, + {} +}; +MODULE_DEVICE_TABLE(of, spi_tegra_of_match_table); +#else /* CONFIG_OF */ +#define spi_tegra_of_match_table NULL +#endif /* CONFIG_OF */ + +static struct platform_driver spi_tegra_driver = { + .driver = { + .name = "spi_tegra", + .owner = THIS_MODULE, + .of_match_table = spi_tegra_of_match_table, + }, + .remove = __devexit_p(spi_tegra_remove), +}; + +static int __init spi_tegra_init(void) +{ + return platform_driver_probe(&spi_tegra_driver, spi_tegra_probe); +} +module_init(spi_tegra_init); + +static void __exit spi_tegra_exit(void) +{ + platform_driver_unregister(&spi_tegra_driver); +} +module_exit(spi_tegra_exit); + +MODULE_LICENSE("GPL"); |