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Release 4.14 drivers/spi/spi-axi-spi-engine.c

Directory: drivers/spi
/*
 * SPI-Engine SPI controller driver
 * Copyright 2015 Analog Devices Inc.
 *  Author: Lars-Peter Clausen <lars@metafoo.de>
 *
 * Licensed under the GPL-2.
 */

#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>


#define SPI_ENGINE_VERSION_MAJOR(x)	((x >> 16) & 0xff)

#define SPI_ENGINE_VERSION_MINOR(x)	((x >> 8) & 0xff)

#define SPI_ENGINE_VERSION_PATCH(x)	(x & 0xff)


#define SPI_ENGINE_REG_VERSION			0x00


#define SPI_ENGINE_REG_RESET			0x40


#define SPI_ENGINE_REG_INT_ENABLE		0x80

#define SPI_ENGINE_REG_INT_PENDING		0x84

#define SPI_ENGINE_REG_INT_SOURCE		0x88


#define SPI_ENGINE_REG_SYNC_ID			0xc0


#define SPI_ENGINE_REG_CMD_FIFO_ROOM		0xd0

#define SPI_ENGINE_REG_SDO_FIFO_ROOM		0xd4

#define SPI_ENGINE_REG_SDI_FIFO_LEVEL		0xd8


#define SPI_ENGINE_REG_CMD_FIFO			0xe0

#define SPI_ENGINE_REG_SDO_DATA_FIFO		0xe4

#define SPI_ENGINE_REG_SDI_DATA_FIFO		0xe8

#define SPI_ENGINE_REG_SDI_DATA_FIFO_PEEK	0xec


#define SPI_ENGINE_INT_CMD_ALMOST_EMPTY		BIT(0)

#define SPI_ENGINE_INT_SDO_ALMOST_EMPTY		BIT(1)

#define SPI_ENGINE_INT_SDI_ALMOST_FULL		BIT(2)

#define SPI_ENGINE_INT_SYNC			BIT(3)


#define SPI_ENGINE_CONFIG_CPHA			BIT(0)

#define SPI_ENGINE_CONFIG_CPOL			BIT(1)

#define SPI_ENGINE_CONFIG_3WIRE			BIT(2)


#define SPI_ENGINE_INST_TRANSFER		0x0

#define SPI_ENGINE_INST_ASSERT			0x1

#define SPI_ENGINE_INST_WRITE			0x2

#define SPI_ENGINE_INST_MISC			0x3


#define SPI_ENGINE_CMD_REG_CLK_DIV		0x0

#define SPI_ENGINE_CMD_REG_CONFIG		0x1


#define SPI_ENGINE_MISC_SYNC			0x0

#define SPI_ENGINE_MISC_SLEEP			0x1


#define SPI_ENGINE_TRANSFER_WRITE		0x1

#define SPI_ENGINE_TRANSFER_READ		0x2


#define SPI_ENGINE_CMD(inst, arg1, arg2) \
	(((inst) << 12) | ((arg1) << 8) | (arg2))


#define SPI_ENGINE_CMD_TRANSFER(flags, n) \
	SPI_ENGINE_CMD(SPI_ENGINE_INST_TRANSFER, (flags), (n))

#define SPI_ENGINE_CMD_ASSERT(delay, cs) \
	SPI_ENGINE_CMD(SPI_ENGINE_INST_ASSERT, (delay), (cs))

#define SPI_ENGINE_CMD_WRITE(reg, val) \
	SPI_ENGINE_CMD(SPI_ENGINE_INST_WRITE, (reg), (val))

#define SPI_ENGINE_CMD_SLEEP(delay) \
	SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SLEEP, (delay))

#define SPI_ENGINE_CMD_SYNC(id) \
	SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SYNC, (id))


struct spi_engine_program {
	
unsigned int length;
	
uint16_t instructions[];
};


struct spi_engine {
	
struct clk *clk;
	
struct clk *ref_clk;

	
spinlock_t lock;

	
void __iomem *base;

	
struct spi_message *msg;
	
struct spi_engine_program *p;
	
unsigned cmd_length;
	
const uint16_t *cmd_buf;

	
struct spi_transfer *tx_xfer;
	
unsigned int tx_length;
	
const uint8_t *tx_buf;

	
struct spi_transfer *rx_xfer;
	
unsigned int rx_length;
	
uint8_t *rx_buf;

	
unsigned int sync_id;
	
unsigned int completed_id;

	
unsigned int int_enable;
};


static void spi_engine_program_add_cmd(struct spi_engine_program *p, bool dry, uint16_t cmd) { if (!dry) p->instructions[p->length] = cmd; p->length++; }

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static unsigned int spi_engine_get_config(struct spi_device *spi) { unsigned int config = 0; if (spi->mode & SPI_CPOL) config |= SPI_ENGINE_CONFIG_CPOL; if (spi->mode & SPI_CPHA) config |= SPI_ENGINE_CONFIG_CPHA; if (spi->mode & SPI_3WIRE) config |= SPI_ENGINE_CONFIG_3WIRE; return config; }

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static unsigned int spi_engine_get_clk_div(struct spi_engine *spi_engine, struct spi_device *spi, struct spi_transfer *xfer) { unsigned int clk_div; clk_div = DIV_ROUND_UP(clk_get_rate(spi_engine->ref_clk), xfer->speed_hz * 2); if (clk_div > 255) clk_div = 255; else if (clk_div > 0) clk_div -= 1; return clk_div; }

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static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry, struct spi_transfer *xfer) { unsigned int len = xfer->len; while (len) { unsigned int n = min(len, 256U); unsigned int flags = 0; if (xfer->tx_buf) flags |= SPI_ENGINE_TRANSFER_WRITE; if (xfer->rx_buf) flags |= SPI_ENGINE_TRANSFER_READ; spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_TRANSFER(flags, n - 1)); len -= n; } }

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static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry, struct spi_engine *spi_engine, unsigned int clk_div, unsigned int delay) { unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk); unsigned int t; if (delay == 0) return; t = DIV_ROUND_UP(delay * spi_clk, (clk_div + 1) * 2); while (t) { unsigned int n = min(t, 256U); spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_SLEEP(n - 1)); t -= n; } }

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static void spi_engine_gen_cs(struct spi_engine_program *p, bool dry, struct spi_device *spi, bool assert) { unsigned int mask = 0xff; if (assert) mask ^= BIT(spi->chip_select); spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(1, mask)); }

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static int spi_engine_compile_message(struct spi_engine *spi_engine, struct spi_message *msg, bool dry, struct spi_engine_program *p) { struct spi_device *spi = msg->spi; struct spi_transfer *xfer; int clk_div, new_clk_div; bool cs_change = true; clk_div = -1; spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG, spi_engine_get_config(spi))); list_for_each_entry(xfer, &msg->transfers, transfer_list) { new_clk_div = spi_engine_get_clk_div(spi_engine, spi, xfer); if (new_clk_div != clk_div) { clk_div = new_clk_div; spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV, clk_div)); } if (cs_change) spi_engine_gen_cs(p, dry, spi, true); spi_engine_gen_xfer(p, dry, xfer); spi_engine_gen_sleep(p, dry, spi_engine, clk_div, xfer->delay_usecs); cs_change = xfer->cs_change; if (list_is_last(&xfer->transfer_list, &msg->transfers)) cs_change = !cs_change; if (cs_change) spi_engine_gen_cs(p, dry, spi, false); } return 0; }

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static void spi_engine_xfer_next(struct spi_engine *spi_engine, struct spi_transfer **_xfer) { struct spi_message *msg = spi_engine->msg; struct spi_transfer *xfer = *_xfer; if (!xfer) { xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list); } else if (list_is_last(&xfer->transfer_list, &msg->transfers)) { xfer = NULL; } else { xfer = list_next_entry(xfer, transfer_list); } *_xfer = xfer; }

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static void spi_engine_tx_next(struct spi_engine *spi_engine) { struct spi_transfer *xfer = spi_engine->tx_xfer; do { spi_engine_xfer_next(spi_engine, &xfer); } while (xfer && !xfer->tx_buf); spi_engine->tx_xfer = xfer; if (xfer) { spi_engine->tx_length = xfer->len; spi_engine->tx_buf = xfer->tx_buf; } else { spi_engine->tx_buf = NULL; } }

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static void spi_engine_rx_next(struct spi_engine *spi_engine) { struct spi_transfer *xfer = spi_engine->rx_xfer; do { spi_engine_xfer_next(spi_engine, &xfer); } while (xfer && !xfer->rx_buf); spi_engine->rx_xfer = xfer; if (xfer) { spi_engine->rx_length = xfer->len; spi_engine->rx_buf = xfer->rx_buf; } else { spi_engine->rx_buf = NULL; } }

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static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine) { void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO; unsigned int n, m, i; const uint16_t *buf; n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM); while (n && spi_engine->cmd_length) { m = min(n, spi_engine->cmd_length); buf = spi_engine->cmd_buf; for (i = 0; i < m; i++) writel_relaxed(buf[i], addr); spi_engine->cmd_buf += m; spi_engine->cmd_length -= m; n -= m; } return spi_engine->cmd_length != 0; }

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static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine) { void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO; unsigned int n, m, i; const uint8_t *buf; n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM); while (n && spi_engine->tx_length) { m = min(n, spi_engine->tx_length); buf = spi_engine->tx_buf; for (i = 0; i < m; i++) writel_relaxed(buf[i], addr); spi_engine->tx_buf += m; spi_engine->tx_length -= m; n -= m; if (spi_engine->tx_length == 0) spi_engine_tx_next(spi_engine); } return spi_engine->tx_length != 0; }

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static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine) { void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO; unsigned int n, m, i; uint8_t *buf; n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL); while (n && spi_engine->rx_length) { m = min(n, spi_engine->rx_length); buf = spi_engine->rx_buf; for (i = 0; i < m; i++) buf[i] = readl_relaxed(addr); spi_engine->rx_buf += m; spi_engine->rx_length -= m; n -= m; if (spi_engine->rx_length == 0) spi_engine_rx_next(spi_engine); } return spi_engine->rx_length != 0; }

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static irqreturn_t spi_engine_irq(int irq, void *devid) { struct spi_master *master = devid; struct spi_engine *spi_engine = spi_master_get_devdata(master); unsigned int disable_int = 0; unsigned int pending; pending = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_INT_PENDING); if (pending & SPI_ENGINE_INT_SYNC) { writel_relaxed(SPI_ENGINE_INT_SYNC, spi_engine->base + SPI_ENGINE_REG_INT_PENDING); spi_engine->completed_id = readl_relaxed( spi_engine->base + SPI_ENGINE_REG_SYNC_ID); } spin_lock(&spi_engine->lock); if (pending & SPI_ENGINE_INT_CMD_ALMOST_EMPTY) { if (!spi_engine_write_cmd_fifo(spi_engine)) disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY; } if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) { if (!spi_engine_write_tx_fifo(spi_engine)) disable_int |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY; } if (pending & (SPI_ENGINE_INT_SDI_ALMOST_FULL | SPI_ENGINE_INT_SYNC)) { if (!spi_engine_read_rx_fifo(spi_engine)) disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL; } if (pending & SPI_ENGINE_INT_SYNC) { if (spi_engine->msg && spi_engine->completed_id == spi_engine->sync_id) { struct spi_message *msg = spi_engine->msg; kfree(spi_engine->p); msg->status = 0; msg->actual_length = msg->frame_length; spi_engine->msg = NULL; spi_finalize_current_message(master); disable_int |= SPI_ENGINE_INT_SYNC; } } if (disable_int) { spi_engine->int_enable &= ~disable_int; writel_relaxed(spi_engine->int_enable, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); } spin_unlock(&spi_engine->lock); return IRQ_HANDLED; }

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static int spi_engine_transfer_one_message(struct spi_master *master, struct spi_message *msg) { struct spi_engine_program p_dry, *p; struct spi_engine *spi_engine = spi_master_get_devdata(master); unsigned int int_enable = 0; unsigned long flags; size_t size; p_dry.length = 0; spi_engine_compile_message(spi_engine, msg, true, &p_dry); size = sizeof(*p->instructions) * (p_dry.length + 1); p = kzalloc(sizeof(*p) + size, GFP_KERNEL); if (!p) return -ENOMEM; spi_engine_compile_message(spi_engine, msg, false, p); spin_lock_irqsave(&spi_engine->lock, flags); spi_engine->sync_id = (spi_engine->sync_id + 1) & 0xff; spi_engine_program_add_cmd(p, false, SPI_ENGINE_CMD_SYNC(spi_engine->sync_id)); spi_engine->msg = msg; spi_engine->p = p; spi_engine->cmd_buf = p->instructions; spi_engine->cmd_length = p->length; if (spi_engine_write_cmd_fifo(spi_engine)) int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY; spi_engine_tx_next(spi_engine); if (spi_engine_write_tx_fifo(spi_engine)) int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY; spi_engine_rx_next(spi_engine); if (spi_engine->rx_length != 0) int_enable |= SPI_ENGINE_INT_SDI_ALMOST_FULL; int_enable |= SPI_ENGINE_INT_SYNC; writel_relaxed(int_enable, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); spi_engine->int_enable = int_enable; spin_unlock_irqrestore(&spi_engine->lock, flags); return 0; }

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static int spi_engine_probe(struct platform_device *pdev) { struct spi_engine *spi_engine; struct spi_master *master; unsigned int version; struct resource *res; int irq; int ret; irq = platform_get_irq(pdev, 0); if (irq <= 0) return -ENXIO; spi_engine = devm_kzalloc(&pdev->dev, sizeof(*spi_engine), GFP_KERNEL); if (!spi_engine) return -ENOMEM; master = spi_alloc_master(&pdev->dev, 0); if (!master) return -ENOMEM; spi_master_set_devdata(master, spi_engine); spin_lock_init(&spi_engine->lock); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); spi_engine->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(spi_engine->base)) { ret = PTR_ERR(spi_engine->base); goto err_put_master; } version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION); if (SPI_ENGINE_VERSION_MAJOR(version) != 1) { dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n", SPI_ENGINE_VERSION_MAJOR(version), SPI_ENGINE_VERSION_MINOR(version), SPI_ENGINE_VERSION_PATCH(version)); ret = -ENODEV; goto err_put_master; } spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk"); if (IS_ERR(spi_engine->clk)) { ret = PTR_ERR(spi_engine->clk); goto err_put_master; } spi_engine->ref_clk = devm_clk_get(&pdev->dev, "spi_clk"); if (IS_ERR(spi_engine->ref_clk)) { ret = PTR_ERR(spi_engine->ref_clk); goto err_put_master; } ret = clk_prepare_enable(spi_engine->clk); if (ret) goto err_put_master; ret = clk_prepare_enable(spi_engine->ref_clk); if (ret) goto err_clk_disable; writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET); writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING); writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); ret = request_irq(irq, spi_engine_irq, 0, pdev->name, master); if (ret) goto err_ref_clk_disable; master->dev.of_node = pdev->dev.of_node; master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE; master->bits_per_word_mask = SPI_BPW_MASK(8); master->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2; master->transfer_one_message = spi_engine_transfer_one_message; master->num_chipselect = 8; ret = spi_register_master(master); if (ret) goto err_free_irq; platform_set_drvdata(pdev, master); return 0; err_free_irq: free_irq(irq, master); err_ref_clk_disable: clk_disable_unprepare(spi_engine->ref_clk); err_clk_disable: clk_disable_unprepare(spi_engine->clk); err_put_master: spi_master_put(master); return ret; }

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static int spi_engine_remove(struct platform_device *pdev) { struct spi_master *master = platform_get_drvdata(pdev); struct spi_engine *spi_engine = spi_master_get_devdata(master); int irq = platform_get_irq(pdev, 0); spi_unregister_master(master); free_irq(irq, master); writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING); writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET); clk_disable_unprepare(spi_engine->ref_clk); clk_disable_unprepare(spi_engine->clk); return 0; }

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static const struct of_device_id spi_engine_match_table[] = { { .compatible = "adi,axi-spi-engine-1.00.a" }, { }, }; MODULE_DEVICE_TABLE(of, spi_engine_match_table); static struct platform_driver spi_engine_driver = { .probe = spi_engine_probe, .remove = spi_engine_remove, .driver = { .name = "spi-engine", .of_match_table = spi_engine_match_table, }, }; module_platform_driver(spi_engine_driver); MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); MODULE_DESCRIPTION("Analog Devices SPI engine peripheral driver"); MODULE_LICENSE("GPL");

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Directory: drivers/spi
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