/* * SPI driver for Nvidia's Tegra20 Serial Flash Controller. * * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. * * Author: Laxman Dewangan <ldewangan@nvidia.com> * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope 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. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <linux/clk.h> #include <linux/completion.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/kthread.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/reset.h> #include <linux/spi/spi.h> #define SPI_COMMAND 0x000 #define SPI_GO BIT(30) #define SPI_M_S BIT(28) #define SPI_ACTIVE_SCLK_MASK (0x3 << 26) #define SPI_ACTIVE_SCLK_DRIVE_LOW (0 << 26) #define SPI_ACTIVE_SCLK_DRIVE_HIGH (1 << 26) #define SPI_ACTIVE_SCLK_PULL_LOW (2 << 26) #define SPI_ACTIVE_SCLK_PULL_HIGH (3 << 26) #define SPI_CK_SDA_FALLING (1 << 21) #define SPI_CK_SDA_RISING (0 << 21) #define SPI_CK_SDA_MASK (1 << 21) #define SPI_ACTIVE_SDA (0x3 << 18) #define SPI_ACTIVE_SDA_DRIVE_LOW (0 << 18) #define SPI_ACTIVE_SDA_DRIVE_HIGH (1 << 18) #define SPI_ACTIVE_SDA_PULL_LOW (2 << 18) #define SPI_ACTIVE_SDA_PULL_HIGH (3 << 18) #define SPI_CS_POL_INVERT BIT(16) #define SPI_TX_EN BIT(15) #define SPI_RX_EN BIT(14) #define SPI_CS_VAL_HIGH BIT(13) #define SPI_CS_VAL_LOW 0x0 #define SPI_CS_SW BIT(12) #define SPI_CS_HW 0x0 #define SPI_CS_DELAY_MASK (7 << 9) #define SPI_CS3_EN BIT(8) #define SPI_CS2_EN BIT(7) #define SPI_CS1_EN BIT(6) #define SPI_CS0_EN BIT(5) #define SPI_CS_MASK (SPI_CS3_EN | SPI_CS2_EN | \ SPI_CS1_EN | SPI_CS0_EN) #define SPI_BIT_LENGTH(x) (((x) & 0x1f) << 0) #define SPI_MODES (SPI_ACTIVE_SCLK_MASK | SPI_CK_SDA_MASK) #define SPI_STATUS 0x004 #define SPI_BSY BIT(31) #define SPI_RDY BIT(30) #define SPI_TXF_FLUSH BIT(29) #define SPI_RXF_FLUSH BIT(28) #define SPI_RX_UNF BIT(27) #define SPI_TX_OVF BIT(26) #define SPI_RXF_EMPTY BIT(25) #define SPI_RXF_FULL BIT(24) #define SPI_TXF_EMPTY BIT(23) #define SPI_TXF_FULL BIT(22) #define SPI_BLK_CNT(count) (((count) & 0xffff) + 1) #define SPI_FIFO_ERROR (SPI_RX_UNF | SPI_TX_OVF) #define SPI_FIFO_EMPTY (SPI_TX_EMPTY | SPI_RX_EMPTY) #define SPI_RX_CMP 0x8 #define SPI_DMA_CTL 0x0C #define SPI_DMA_EN BIT(31) #define SPI_IE_RXC BIT(27) #define SPI_IE_TXC BIT(26) #define SPI_PACKED BIT(20) #define SPI_RX_TRIG_MASK (0x3 << 18) #define SPI_RX_TRIG_1W (0x0 << 18) #define SPI_RX_TRIG_4W (0x1 << 18) #define SPI_TX_TRIG_MASK (0x3 << 16) #define SPI_TX_TRIG_1W (0x0 << 16) #define SPI_TX_TRIG_4W (0x1 << 16) #define SPI_DMA_BLK_COUNT(count) (((count) - 1) & 0xFFFF) #define SPI_TX_FIFO 0x10 #define SPI_RX_FIFO 0x20 #define DATA_DIR_TX (1 << 0) #define DATA_DIR_RX (1 << 1) #define MAX_CHIP_SELECT 4 #define SPI_FIFO_DEPTH 4 #define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000)) struct tegra_sflash_data { struct device *dev; struct spi_master *master; spinlock_t lock; struct clk *clk; struct reset_control *rst; void __iomem *base; unsigned irq; u32 cur_speed; struct spi_device *cur_spi; unsigned cur_pos; unsigned cur_len; unsigned bytes_per_word; unsigned cur_direction; unsigned curr_xfer_words; unsigned cur_rx_pos; unsigned cur_tx_pos; u32 tx_status; u32 rx_status; u32 status_reg; u32 def_command_reg; u32 command_reg; u32 dma_control_reg; struct completion xfer_completion; struct spi_transfer *curr_xfer; }; static int tegra_sflash_runtime_suspend(struct device *dev); static int tegra_sflash_runtime_resume(struct device *dev); static inline u32 tegra_sflash_readl(struct tegra_sflash_data *tsd, unsigned long reg) { return readl(tsd->base + reg); } static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd, u32 val, unsigned long reg) { writel(val, tsd->base + reg); } static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd) { /* Write 1 to clear status register */ tegra_sflash_writel(tsd, SPI_RDY | SPI_FIFO_ERROR, SPI_STATUS); } static unsigned tegra_sflash_calculate_curr_xfer_param( struct spi_device *spi, struct tegra_sflash_data *tsd, struct spi_transfer *t) { unsigned remain_len = t->len - tsd->cur_pos; unsigned max_word; tsd->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8); max_word = remain_len / tsd->bytes_per_word; if (max_word > SPI_FIFO_DEPTH) max_word = SPI_FIFO_DEPTH; tsd->curr_xfer_words = max_word; return max_word; } static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf( struct tegra_sflash_data *tsd, struct spi_transfer *t) { unsigned nbytes; u32 status; unsigned max_n_32bit = tsd->curr_xfer_words; u8 *tx_buf = (u8 *)t->tx_buf + tsd->cur_tx_pos; if (max_n_32bit > SPI_FIFO_DEPTH) max_n_32bit = SPI_FIFO_DEPTH; nbytes = max_n_32bit * tsd->bytes_per_word; status = tegra_sflash_readl(tsd, SPI_STATUS); while (!(status & SPI_TXF_FULL)) { int i; u32 x = 0; for (i = 0; nbytes && (i < tsd->bytes_per_word); i++, nbytes--) x |= (u32)(*tx_buf++) << (i * 8); tegra_sflash_writel(tsd, x, SPI_TX_FIFO); if (!nbytes) break; status = tegra_sflash_readl(tsd, SPI_STATUS); } tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word; return max_n_32bit; } static int tegra_sflash_read_rx_fifo_to_client_rxbuf( struct tegra_sflash_data *tsd, struct spi_transfer *t) { u32 status; unsigned int read_words = 0; u8 *rx_buf = (u8 *)t->rx_buf + tsd->cur_rx_pos; status = tegra_sflash_readl(tsd, SPI_STATUS); while (!(status & SPI_RXF_EMPTY)) { int i; u32 x = tegra_sflash_readl(tsd, SPI_RX_FIFO); for (i = 0; (i < tsd->bytes_per_word); i++) *rx_buf++ = (x >> (i*8)) & 0xFF; read_words++; status = tegra_sflash_readl(tsd, SPI_STATUS); } tsd->cur_rx_pos += read_words * tsd->bytes_per_word; return 0; } static int tegra_sflash_start_cpu_based_transfer( struct tegra_sflash_data *tsd, struct spi_transfer *t) { u32 val = 0; unsigned cur_words; if (tsd->cur_direction & DATA_DIR_TX) val |= SPI_IE_TXC; if (tsd->cur_direction & DATA_DIR_RX) val |= SPI_IE_RXC; tegra_sflash_writel(tsd, val, SPI_DMA_CTL); tsd->dma_control_reg = val; if (tsd->cur_direction & DATA_DIR_TX) cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t); else cur_words = tsd->curr_xfer_words; val |= SPI_DMA_BLK_COUNT(cur_words); tegra_sflash_writel(tsd, val, SPI_DMA_CTL); tsd->dma_control_reg = val; val |= SPI_DMA_EN; tegra_sflash_writel(tsd, val, SPI_DMA_CTL); return 0; } static int tegra_sflash_start_transfer_one(struct spi_device *spi, struct spi_transfer *t, bool is_first_of_msg, bool is_single_xfer) { struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master); u32 speed; u32 command; speed = t->speed_hz; if (speed != tsd->cur_speed) { clk_set_rate(tsd->clk, speed); tsd->cur_speed = speed; } tsd->cur_spi = spi; tsd->cur_pos = 0; tsd->cur_rx_pos = 0; tsd->cur_tx_pos = 0; tsd->curr_xfer = t; tegra_sflash_calculate_curr_xfer_param(spi, tsd, t); if (is_first_of_msg) { command = tsd->def_command_reg; command |= SPI_BIT_LENGTH(t->bits_per_word - 1); command |= SPI_CS_VAL_HIGH; command &= ~SPI_MODES; if (spi->mode & SPI_CPHA) command |= SPI_CK_SDA_FALLING; if (spi->mode & SPI_CPOL) command |= SPI_ACTIVE_SCLK_DRIVE_HIGH; else command |= SPI_ACTIVE_SCLK_DRIVE_LOW; command |= SPI_CS0_EN << spi->chip_select; } else { command = tsd->command_reg; command &= ~SPI_BIT_LENGTH(~0); command |= SPI_BIT_LENGTH(t->bits_per_word - 1); command &= ~(SPI_RX_EN | SPI_TX_EN); } tsd->cur_direction = 0; if (t->rx_buf) { command |= SPI_RX_EN; tsd->cur_direction |= DATA_DIR_RX; } if (t->tx_buf) { command |= SPI_TX_EN; tsd->cur_direction |= DATA_DIR_TX; } tegra_sflash_writel(tsd, command, SPI_COMMAND); tsd->command_reg = command; return tegra_sflash_start_cpu_based_transfer(tsd, t); } static int tegra_sflash_transfer_one_message(struct spi_master *master, struct spi_message *msg) { bool is_first_msg = true; int single_xfer; struct tegra_sflash_data *tsd = spi_master_get_devdata(master); struct spi_transfer *xfer; struct spi_device *spi = msg->spi; int ret; msg->status = 0; msg->actual_length = 0; single_xfer = list_is_singular(&msg->transfers); list_for_each_entry(xfer, &msg->transfers, transfer_list) { reinit_completion(&tsd->xfer_completion); ret = tegra_sflash_start_transfer_one(spi, xfer, is_first_msg, single_xfer); if (ret < 0) { dev_err(tsd->dev, "spi can not start transfer, err %d\n", ret); goto exit; } is_first_msg = false; ret = wait_for_completion_timeout(&tsd->xfer_completion, SPI_DMA_TIMEOUT); if (WARN_ON(ret == 0)) { dev_err(tsd->dev, "spi trasfer timeout, err %d\n", ret); ret = -EIO; goto exit; } if (tsd->tx_status || tsd->rx_status) { dev_err(tsd->dev, "Error in Transfer\n"); ret = -EIO; goto exit; } msg->actual_length += xfer->len; if (xfer->cs_change && xfer->delay_usecs) { tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND); udelay(xfer->delay_usecs); } } ret = 0; exit: tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND); msg->status = ret; spi_finalize_current_message(master); return ret; } static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd) { struct spi_transfer *t = tsd->curr_xfer; unsigned long flags; spin_lock_irqsave(&tsd->lock, flags); if (tsd->tx_status || tsd->rx_status || (tsd->status_reg & SPI_BSY)) { dev_err(tsd->dev, "CpuXfer ERROR bit set 0x%x\n", tsd->status_reg); dev_err(tsd->dev, "CpuXfer 0x%08x:0x%08x\n", tsd->command_reg, tsd->dma_control_reg); reset_control_assert(tsd->rst); udelay(2); reset_control_deassert(tsd->rst); complete(&tsd->xfer_completion); goto exit; } if (tsd->cur_direction & DATA_DIR_RX) tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t); if (tsd->cur_direction & DATA_DIR_TX) tsd->cur_pos = tsd->cur_tx_pos; else tsd->cur_pos = tsd->cur_rx_pos; if (tsd->cur_pos == t->len) { complete(&tsd->xfer_completion); goto exit; } tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t); tegra_sflash_start_cpu_based_transfer(tsd, t); exit: spin_unlock_irqrestore(&tsd->lock, flags); return IRQ_HANDLED; } static irqreturn_t tegra_sflash_isr(int irq, void *context_data) { struct tegra_sflash_data *tsd = context_data; tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS); if (tsd->cur_direction & DATA_DIR_TX) tsd->tx_status = tsd->status_reg & SPI_TX_OVF; if (tsd->cur_direction & DATA_DIR_RX) tsd->rx_status = tsd->status_reg & SPI_RX_UNF; tegra_sflash_clear_status(tsd); return handle_cpu_based_xfer(tsd); } static const struct of_device_id tegra_sflash_of_match[] = { { .compatible = "nvidia,tegra20-sflash", }, {} }; MODULE_DEVICE_TABLE(of, tegra_sflash_of_match); static int tegra_sflash_probe(struct platform_device *pdev) { struct spi_master *master; struct tegra_sflash_data *tsd; struct resource *r; int ret; const struct of_device_id *match; match = of_match_device(tegra_sflash_of_match, &pdev->dev); if (!match) { dev_err(&pdev->dev, "Error: No device match found\n"); return -ENODEV; } master = spi_alloc_master(&pdev->dev, sizeof(*tsd)); if (!master) { 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; master->transfer_one_message = tegra_sflash_transfer_one_message; master->auto_runtime_pm = true; master->num_chipselect = MAX_CHIP_SELECT; platform_set_drvdata(pdev, master); tsd = spi_master_get_devdata(master); tsd->master = master; tsd->dev = &pdev->dev; spin_lock_init(&tsd->lock); if (of_property_read_u32(tsd->dev->of_node, "spi-max-frequency", &master->max_speed_hz)) master->max_speed_hz = 25000000; /* 25MHz */ r = platform_get_resource(pdev, IORESOURCE_MEM, 0); tsd->base = devm_ioremap_resource(&pdev->dev, r); if (IS_ERR(tsd->base)) { ret = PTR_ERR(tsd->base); goto exit_free_master; } tsd->irq = platform_get_irq(pdev, 0); ret = request_irq(tsd->irq, tegra_sflash_isr, 0, dev_name(&pdev->dev), tsd); if (ret < 0) { dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n", tsd->irq); goto exit_free_master; } tsd->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(tsd->clk)) { dev_err(&pdev->dev, "can not get clock\n"); ret = PTR_ERR(tsd->clk); goto exit_free_irq; } tsd->rst = devm_reset_control_get(&pdev->dev, "spi"); if (IS_ERR(tsd->rst)) { dev_err(&pdev->dev, "can not get reset\n"); ret = PTR_ERR(tsd->rst); goto exit_free_irq; } init_completion(&tsd->xfer_completion); pm_runtime_enable(&pdev->dev); if (!pm_runtime_enabled(&pdev->dev)) { ret = tegra_sflash_runtime_resume(&pdev->dev); if (ret) goto exit_pm_disable; } ret = pm_runtime_get_sync(&pdev->dev); if (ret < 0) { dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret); goto exit_pm_disable; } /* Reset controller */ reset_control_assert(tsd->rst); udelay(2); reset_control_deassert(tsd->rst); tsd->def_command_reg = SPI_M_S | SPI_CS_SW; tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND); pm_runtime_put(&pdev->dev); master->dev.of_node = pdev->dev.of_node; ret = devm_spi_register_master(&pdev->dev, master); if (ret < 0) { dev_err(&pdev->dev, "can not register to master err %d\n", ret); goto exit_pm_disable; } return ret; exit_pm_disable: pm_runtime_disable(&pdev->dev); if (!pm_runtime_status_suspended(&pdev->dev)) tegra_sflash_runtime_suspend(&pdev->dev); exit_free_irq: free_irq(tsd->irq, tsd); exit_free_master: spi_master_put(master); return ret; } static int tegra_sflash_remove(struct platform_device *pdev) { struct spi_master *master = platform_get_drvdata(pdev); struct tegra_sflash_data *tsd = spi_master_get_devdata(master); free_irq(tsd->irq, tsd); pm_runtime_disable(&pdev->dev); if (!pm_runtime_status_suspended(&pdev->dev)) tegra_sflash_runtime_suspend(&pdev->dev); return 0; } #ifdef CONFIG_PM_SLEEP static int tegra_sflash_suspend(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); return spi_master_suspend(master); } static int tegra_sflash_resume(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct tegra_sflash_data *tsd = spi_master_get_devdata(master); int ret; ret = pm_runtime_get_sync(dev); if (ret < 0) { dev_err(dev, "pm runtime failed, e = %d\n", ret); return ret; } tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND); pm_runtime_put(dev); return spi_master_resume(master); } #endif static int tegra_sflash_runtime_suspend(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct tegra_sflash_data *tsd = spi_master_get_devdata(master); /* Flush all write which are in PPSB queue by reading back */ tegra_sflash_readl(tsd, SPI_COMMAND); clk_disable_unprepare(tsd->clk); return 0; } static int tegra_sflash_runtime_resume(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct tegra_sflash_data *tsd = spi_master_get_devdata(master); int ret; ret = clk_prepare_enable(tsd->clk); if (ret < 0) { dev_err(tsd->dev, "clk_prepare failed: %d\n", ret); return ret; } return 0; } static const struct dev_pm_ops slink_pm_ops = { SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend, tegra_sflash_runtime_resume, NULL) SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume) }; static struct platform_driver tegra_sflash_driver = { .driver = { .name = "spi-tegra-sflash", .pm = &slink_pm_ops, .of_match_table = tegra_sflash_of_match, }, .probe = tegra_sflash_probe, .remove = tegra_sflash_remove, }; module_platform_driver(tegra_sflash_driver); MODULE_ALIAS("platform:spi-tegra-sflash"); MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver"); MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); MODULE_LICENSE("GPL v2");