// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
/*
 * Copyright (c) 2019 Amlogic, Inc. All rights reserved.
 */

#include <linux/dmaengine.h>
#include <linux/iopoll.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>
#include <linux/module.h>
#include <linux/amlogic/aml_spi_mem.h>

#define SPI_MEM_MAX_BUSWIDTH		8

u8 xfer_flag;
static struct spi_transfer xfers[4];
static struct spi_message msg;

static bool spi_mem_buswidth_is_valid(u8 buswidth)
{
	if (hweight8(buswidth) > 1 || buswidth > SPI_MEM_MAX_BUSWIDTH)
		return false;

	return true;
}

static int spi_mem_check_op(const struct spi_mem_op *op)
{
	if (!op->cmd.buswidth || !op->cmd.nbytes)
		return -EINVAL;

	if ((op->addr.nbytes && !op->addr.buswidth) ||
	    (op->dummy.nbytes && !op->dummy.buswidth) ||
	    (op->data.nbytes && !op->data.buswidth))
		return -EINVAL;

	if (!spi_mem_buswidth_is_valid(op->cmd.buswidth) ||
	    !spi_mem_buswidth_is_valid(op->addr.buswidth) ||
	    !spi_mem_buswidth_is_valid(op->dummy.buswidth) ||
	    !spi_mem_buswidth_is_valid(op->data.buswidth))
		return -EINVAL;

	return 0;
}

static bool spi_mem_internal_supports_op(struct spi_mem *mem,
					 const struct spi_mem_op *op)
{
	struct spi_controller *ctlr = mem->spi->controller;

	if (ctlr->mem_ops && ctlr->mem_ops->supports_op)
		return ctlr->mem_ops->supports_op(mem, op);

	return spi_mem_default_supports_op(mem, op);
}

static int spi_mem_access_start(struct spi_mem *mem)
{
	struct spi_controller *ctlr = mem->spi->controller;

	/*
	 * Flush the message queue before executing our SPI memory
	 * operation to prevent preemption of regular SPI transfers.
	 */
	//spi_flush_queue(ctlr);

	if (ctlr->auto_runtime_pm) {
		int ret;

		ret = pm_runtime_get_sync(ctlr->dev.parent);
		if (ret < 0) {
			pm_runtime_put_noidle(ctlr->dev.parent);
			dev_err(&ctlr->dev, "Failed to power device: %d\n",
				ret);
			return ret;
		}
	}

	mutex_lock(&ctlr->bus_lock_mutex);
	mutex_lock(&ctlr->io_mutex);

	return 0;
}

static void spi_mem_access_end(struct spi_mem *mem)
{
	struct spi_controller *ctlr = mem->spi->controller;

	mutex_unlock(&ctlr->io_mutex);
	mutex_unlock(&ctlr->bus_lock_mutex);

	if (ctlr->auto_runtime_pm)
		pm_runtime_put(ctlr->dev.parent);
}

static void spi_mem_add_op_stats(struct spi_statistics __percpu *pcpu_stats,
				 const struct spi_mem_op *op, int exec_op_ret)
{
	struct spi_statistics *stats;
	u64 len, l2len = 0;

	get_cpu();
	stats = this_cpu_ptr(pcpu_stats);
	u64_stats_update_begin(&stats->syncp);

	/*
	 * We do not have the concept of messages or transfers. Let's consider
	 * that one operation is equivalent to one message and one transfer.
	 */
	u64_stats_inc(&stats->messages);
	u64_stats_inc(&stats->transfers);

	/* Use the sum of all lengths as bytes count and histogram value. */
	len = op->cmd.nbytes + op->addr.nbytes;
	len += op->dummy.nbytes + op->data.nbytes;
	u64_stats_add(&stats->bytes, len);
	if (len != 0)
		l2len = min(fls(len), SPI_STATISTICS_HISTO_SIZE) - 1;
	u64_stats_inc(&stats->transfer_bytes_histo[l2len]);

	/* Only account for data bytes as transferred bytes. */
	if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
		u64_stats_add(&stats->bytes_tx, op->data.nbytes);
	if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
		u64_stats_add(&stats->bytes_rx, op->data.nbytes);

	/*
	 * A timeout is not an error, following the same behavior as
	 * spi_transfer_one_message().
	 */
	if (exec_op_ret == -ETIMEDOUT)
		u64_stats_inc(&stats->timedout);
	else if (exec_op_ret)
		u64_stats_inc(&stats->errors);

	u64_stats_update_end(&stats->syncp);
	put_cpu();
}

/**
 * meson_spi_mem_exec_op() - Execute a memory operation
 * @mem: the SPI memory
 * @op: the memory operation to execute
 *
 * Executes a memory operation.
 *
 * This function first checks that @op is supported and then tries to execute
 * it.
 *
 * Return: 0 in case of success, a negative error code otherwise.
 */
int meson_spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
	unsigned int tmpbufsize, xferpos = 0, totalxferlen = 0;
	struct spi_controller *ctlr = mem->spi->controller;
	u8 *tmpbuf;
	int ret;

	ret = spi_mem_check_op(op);
	if (ret)
		return ret;

	if (!spi_mem_internal_supports_op(mem, op))
		return -EOPNOTSUPP;

	if (ctlr->mem_ops && ctlr->mem_ops->exec_op && !spi_get_csgpiod(mem->spi, 0)) {
		ret = spi_mem_access_start(mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->exec_op(mem, op);

		spi_mem_access_end(mem);

		/*
		 * Some controllers only optimize specific paths (typically the
		 * read path) and expect the core to use the regular SPI
		 * interface in other cases.
		 */
		if (!ret || ret != -EOPNOTSUPP) {
			spi_mem_add_op_stats(ctlr->pcpu_statistics, op, ret);
			spi_mem_add_op_stats(mem->spi->pcpu_statistics, op, ret);

			return ret;
		}
	}

	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;

	/*
	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
	 * we're guaranteed that this buffer is DMA-able, as required by the
	 * SPI layer.
	 */
	tmpbuf = kzalloc(tmpbufsize, GFP_KERNEL | GFP_DMA);
	if (!tmpbuf)
		return -ENOMEM;

	spi_message_init(&msg);
	memset(xfers, 0, sizeof(xfers));

	tmpbuf[0] = op->cmd.opcode;
	/* use rx_nbits to ident cmd stage */
	xfers[xferpos].rx_nbits = 1;
	xfers[xferpos].tx_buf = tmpbuf;
	xfers[xferpos].len = op->cmd.nbytes;
	xfers[xferpos].tx_nbits = op->cmd.buswidth;
	spi_message_add_tail(&xfers[xferpos], &msg);
	xferpos++;
	totalxferlen++;

	if (op->addr.nbytes) {
		int i;

		for (i = 0; i < op->addr.nbytes; i++)
			tmpbuf[i + 1] = op->addr.val >>
					(8 * (op->addr.nbytes - i - 1));

		/* use rx_nbits to ident addr stage */
		xfers[xferpos].rx_nbits = 2;
		xfers[xferpos].tx_buf = tmpbuf + 1;
		xfers[xferpos].len = op->addr.nbytes;
		xfers[xferpos].tx_nbits = op->addr.buswidth;
		spi_message_add_tail(&xfers[xferpos], &msg);
		xferpos++;
		totalxferlen += op->addr.nbytes;
	}

	if (op->dummy.nbytes) {
		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
		/* use rx_nbits to ident dummy stage */
		xfers[xferpos].rx_nbits = 3;
		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
		xfers[xferpos].len = op->dummy.nbytes;
		xfers[xferpos].tx_nbits = op->dummy.buswidth;
		xfers[xferpos].dummy_data = 1;
		spi_message_add_tail(&xfers[xferpos], &msg);
		xferpos++;
		totalxferlen += op->dummy.nbytes;
	}

	if (op->data.nbytes) {
		if (op->data.dir == SPI_MEM_DATA_IN) {
			xfers[xferpos].rx_buf = op->data.buf.in;
			xfers[xferpos].rx_nbits = op->data.buswidth;
		} else {
			xfers[xferpos].tx_buf = op->data.buf.out;
			xfers[xferpos].tx_nbits = op->data.buswidth;
		}

		xfers[xferpos].len = op->data.nbytes;
		spi_message_add_tail(&xfers[xferpos], &msg);
		xferpos++;
		totalxferlen += op->data.nbytes;
	}

	ret = spi_sync(mem->spi, &msg);

	kfree(tmpbuf);

	if (ret)
		return ret;

	if (msg.actual_length != totalxferlen)
		return -EIO;

	return 0;
}
EXPORT_SYMBOL_GPL(meson_spi_mem_exec_op);

static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc,
				      u64 offs, size_t len, void *buf)
{
	struct spi_mem_op op = desc->info.op_tmpl;
	int ret;

	op.addr.val = desc->info.offset + offs;
	op.data.buf.in = buf;
	op.data.nbytes = len;
	ret = spi_mem_adjust_op_size(desc->mem, &op);
	if (ret)
		return ret;

	ret = meson_spi_mem_exec_op(desc->mem, &op);
	if (ret)
		return ret;

	return op.data.nbytes;
}

static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc,
				       u64 offs, size_t len, const void *buf)
{
	struct spi_mem_op op = desc->info.op_tmpl;
	int ret;

	op.addr.val = desc->info.offset + offs;
	op.data.buf.out = buf;
	op.data.nbytes = len;
	ret = spi_mem_adjust_op_size(desc->mem, &op);
	if (ret)
		return ret;

	ret = meson_spi_mem_exec_op(desc->mem, &op);
	if (ret)
		return ret;

	return op.data.nbytes;
}

/**
 * meson_spi_mem_dirmap_read() - Read data through a direct mapping
 * @desc: direct mapping descriptor
 * @offs: offset to start reading from. Note that this is not an absolute
 *	  offset, but the offset within the direct mapping which already has
 *	  its own offset
 * @len: length in bytes
 * @buf: destination buffer. This buffer must be DMA-able
 *
 * This function reads data from a memory device using a direct mapping
 * previously instantiated with spi_mem_dirmap_create().
 *
 * Return: the amount of data read from the memory device or a negative error
 * code. Note that the returned size might be smaller than @len, and the caller
 * is responsible for calling meson_spi_mem_dirmap_read() again when that happens.
 */
ssize_t meson_spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
			    u64 offs, size_t len, void *buf)
{
	struct spi_controller *ctlr = desc->mem->spi->controller;
	ssize_t ret;

	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
		return -EINVAL;

	if (!len)
		return 0;

	if (desc->nodirmap) {
		ret = spi_mem_no_dirmap_read(desc, offs, len, buf);
	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_read) {
		ret = spi_mem_access_start(desc->mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->dirmap_read(desc, offs, len, buf);

		spi_mem_access_end(desc->mem);
	} else {
		ret = -EOPNOTSUPP;
	}

	return ret;
}
EXPORT_SYMBOL_GPL(meson_spi_mem_dirmap_read);

/**
 * meson_spi_mem_dirmap_write() - Write data through a direct mapping
 * @desc: direct mapping descriptor
 * @offs: offset to start writing from. Note that this is not an absolute
 *	  offset, but the offset within the direct mapping which already has
 *	  its own offset
 * @len: length in bytes
 * @buf: source buffer. This buffer must be DMA-able
 *
 * This function writes data to a memory device using a direct mapping
 * previously instantiated with spi_mem_dirmap_create().
 *
 * Return: the amount of data written to the memory device or a negative error
 * code. Note that the returned size might be smaller than @len, and the caller
 * is responsible for calling spi_mem_dirmap_write() again when that happens.
 */
ssize_t meson_spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
			     u64 offs, size_t len, const void *buf)
{
	struct spi_controller *ctlr = desc->mem->spi->controller;
	ssize_t ret;

	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT)
		return -EINVAL;

	if (!len)
		return 0;

	if (desc->nodirmap) {
		ret = spi_mem_no_dirmap_write(desc, offs, len, buf);
	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_write) {
		ret = spi_mem_access_start(desc->mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->dirmap_write(desc, offs, len, buf);

		spi_mem_access_end(desc->mem);
	} else {
		ret = -EOPNOTSUPP;
	}

	return ret;
}
EXPORT_SYMBOL_GPL(meson_spi_mem_dirmap_write);

static int spi_mem_read_status(struct spi_mem *mem,
			       const struct spi_mem_op *op,
			       u16 *status)
{
	const u8 *bytes = (u8 *)op->data.buf.in;
	int ret;

	ret = meson_spi_mem_exec_op(mem, op);
	if (ret)
		return ret;

	if (op->data.nbytes > 1)
		*status = ((u16)bytes[0] << 8) | bytes[1];
	else
		*status = bytes[0];

	return 0;
}

/**
 * meson_spi_mem_poll_status() - Poll memory device status
 * @mem: SPI memory device
 * @op: the memory operation to execute
 * @mask: status bitmask to ckeck
 * @match: (status & mask) expected value
 * @initial_delay_us: delay in us before starting to poll
 * @polling_delay_us: time to sleep between reads in us
 * @timeout_ms: timeout in milliseconds
 *
 * This function polls a status register and returns when
 * (status & mask) == match or when the timeout has expired.
 *
 * Return: 0 in case of success, -ETIMEDOUT in case of error,
 *         -EOPNOTSUPP if not supported.
 */
int meson_spi_mem_poll_status(struct spi_mem *mem,
			const struct spi_mem_op *op,
			u16 mask, u16 match,
			unsigned long initial_delay_us,
			unsigned long polling_delay_us,
			u16 timeout_ms)
{
	struct spi_controller *ctlr = mem->spi->controller;
	int ret = -EOPNOTSUPP;
	int read_status_ret;
	u16 status;

	if (op->data.nbytes < 1 || op->data.nbytes > 2 ||
	    op->data.dir != SPI_MEM_DATA_IN)
		return -EINVAL;

	if (ctlr->mem_ops && ctlr->mem_ops->poll_status) {
		ret = spi_mem_access_start(mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->poll_status(mem, op, mask, match,
						 initial_delay_us, polling_delay_us,
						 timeout_ms);

		spi_mem_access_end(mem);
	}

	if (ret == -EOPNOTSUPP) {
		if (!spi_mem_supports_op(mem, op))
			return ret;

		if (initial_delay_us < 10)
			udelay(initial_delay_us);
		else
			usleep_range((initial_delay_us >> 2) + 1,
				     initial_delay_us);

		ret = read_poll_timeout(spi_mem_read_status, read_status_ret,
					(read_status_ret || ((status) & mask) == match),
					polling_delay_us, timeout_ms * 1000, false, mem,
					op, &status);
		if (read_status_ret)
			return read_status_ret;
	}

	return ret;
}

void spi_mem_set_xfer_flag(u8 flag)
{
	xfer_flag |= flag;
}
EXPORT_SYMBOL_GPL(spi_mem_set_xfer_flag);

u8 spi_mem_get_xfer_flag(void)
{
	return xfer_flag;
}
EXPORT_SYMBOL_GPL(spi_mem_get_xfer_flag);

void spi_mem_umask_xfer_flags(void)
{
	xfer_flag &= ~SPI_XFER_NFC_MASK_FLAG;
}
EXPORT_SYMBOL_GPL(spi_mem_umask_xfer_flags);

struct mtd_info *spi_nfc_mtd;
void spi_mem_set_mtd(struct mtd_info *mtd)
{
	spi_nfc_mtd = mtd;
}
EXPORT_SYMBOL_GPL(spi_mem_set_mtd);

struct mtd_info *spi_mem_get_mtd(void)
{
	return spi_nfc_mtd;
}
EXPORT_SYMBOL_GPL(spi_mem_get_mtd);

EXPORT_SYMBOL_GPL(meson_spi_mem_poll_status);
MODULE_LICENSE("GPL v2");