/*
 * Copyright (c) 2011 The Chromium OS Authors.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

/* This file is derived from the flashrom project. */

#include <common.h>
#include <malloc.h>
#include <pci.h>
#include <pci_ids.h>

#include <spi.h>

#include <asm/io.h>

typedef struct spi_slave ich_spi_slave;

static int ichspi_lock = 0;

typedef struct ich7_spi_regs {
	uint16_t spis;
	uint16_t spic;
	uint32_t spia;
	uint64_t spid[8];
	uint64_t _pad;
	uint32_t bbar;
	uint16_t preop;
	uint16_t optype;
	uint8_t opmenu[8];
} __attribute__((packed)) ich7_spi_regs;

typedef struct ich9_spi_regs {
	uint32_t bfpr;
	uint16_t hsfs;
	uint16_t hsfc;
	uint32_t faddr;
	uint32_t _reserved0;
	uint32_t fdata[16];
	uint32_t frap;
	uint32_t freg[5];
	uint32_t _reserved1[3];
	uint32_t pr[5];
	uint32_t _reserved2[2];
	uint8_t ssfs;
	uint8_t ssfc[3];
	uint16_t preop;
	uint16_t optype;
	uint8_t opmenu[8];
	uint32_t bbar;
	uint8_t _reserved3[12];
	uint32_t fdoc;
	uint32_t fdod;
	uint8_t _reserved4[8];
	uint32_t afc;
	uint32_t lvscc;
	uint32_t uvscc;
	uint8_t _reserved5[4];
	uint32_t fpb;
	uint8_t _reserved6[28];
	uint32_t srdl;
	uint32_t srdc;
	uint32_t srd;
} __attribute__((packed)) ich9_spi_regs;

typedef struct ich_spi_controller {
	int locked;

	uint8_t *opmenu;
	int menubytes;
	uint16_t *preop;
	uint16_t *optype;
	uint32_t *addr;
	uint8_t *data;
	unsigned databytes;
	uint8_t *status;
	uint16_t *control;
	uint32_t *bbar;
} ich_spi_controller;

static ich_spi_controller cntlr;

enum {
	SPIS_SCIP =		0x0001,
	SPIS_GRANT =		0x0002,
	SPIS_CDS =		0x0004,
	SPIS_FCERR =		0x0008,
	SSFS_AEL =		0x0010,
	SPIS_LOCK =		0x8000,
	SPIS_RESERVED_MASK =	0x7ff0,
	SSFS_RESERVED_MASK =	0x7fe2
};

enum {
	SPIC_SCGO =		0x000002,
	SPIC_ACS =		0x000004,
	SPIC_SPOP =		0x000008,
	SPIC_DBC =		0x003f00,
	SPIC_DS =		0x004000,
	SPIC_SME =		0x008000,
	SSFC_SCF_MASK =		0x070000,
	SSFC_RESERVED =		0xf80000
};

enum {
	HSFS_FDONE =		0x0001,
	HSFS_FCERR =		0x0002,
	HSFS_AEL =		0x0004,
	HSFS_BERASE_MASK =	0x0018,
	HSFS_BERASE_SHIFT =	3,
	HSFS_SCIP =		0x0020,
	HSFS_FDOPSS =		0x2000,
	HSFS_FDV =		0x4000,
	HSFS_FLOCKDN =		0x8000
};

enum {
	HSFC_FGO =		0x0001,
	HSFC_FCYCLE_MASK =	0x0006,
	HSFC_FCYCLE_SHIFT =	1,
	HSFC_FDBC_MASK =	0x3f00,
	HSFC_FDBC_SHIFT =	8,
	HSFC_FSMIE =		0x8000
};

enum {
	SPI_OPCODE_TYPE_READ_NO_ADDRESS =	0,
	SPI_OPCODE_TYPE_WRITE_NO_ADDRESS =	1,
	SPI_OPCODE_TYPE_READ_WITH_ADDRESS =	2,
	SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS =	3
};

#ifdef DEBUG

static u8 readb_(const void *addr)
{
	u8 v = readb(addr);
	printf("read %2.2x from %4.4x\n",
	       v, ((unsigned) addr & 0xffff) - 0xf020);
	return v;
}

static u16 readw_(const void *addr)
{
	u16 v = readw(addr);
	printf("read %4.4x from %4.4x\n",
	       v, ((unsigned) addr & 0xffff) - 0xf020);
	return v;
}

static u32 readl_(const void *addr)
{
	u32 v = readl(addr);
	printf("read %8.8x from %4.4x\n",
	       v, ((unsigned) addr & 0xffff) - 0xf020);
	return v;
}

static void writeb_(u8 b, const void *addr)
{
	writeb(b, addr);
	printf("wrote %2.2x to %4.4x\n",
	       b, ((unsigned) addr & 0xffff) - 0xf020);
}

static void writew_(u16 b, const void *addr)
{
	writew(b, addr);
	printf("wrote %4.4x to %4.4x\n",
	       b, ((unsigned) addr & 0xffff) - 0xf020);
}

static void writel_(u32 b, const void *addr)
{
	writel(b, addr);
	printf("wrote %8.8x to %4.4x\n",
	       b, ((unsigned) addr & 0xffff) - 0xf020);
}

#else /* DEBUG ^^^ defined  vvv NOT defined */

#define readb_(a) readb(a)
#define readw_(a) readw(a)
#define readl_(a) readl(a)
#define writeb_(a, b) writeb(a, b)
#define writew_(a, b) writew(a, b)
#define writel_(a, b) writel(a, b)

#endif  /* DEBUG ^^^ NOT defined */

static void write_reg(const void *value, void *dest, uint32_t size)
{
	const uint8_t *bvalue = value;
	uint8_t *bdest = dest;

	while (size >= 4) {
		writel_(*(const uint32_t *)bvalue, bdest);
		bdest += 4; bvalue += 4; size -= 4;
	}
	while (size) {
		writeb_(*bvalue, bdest);
		bdest++; bvalue++; size--;
	}
}

static void read_reg(const void *src, void *value, uint32_t size)
{
	const uint8_t *bsrc = src;
	uint8_t *bvalue = value;

	while (size >= 4) {
		*(uint32_t *)bvalue = readl_(bsrc);
		bsrc += 4; bvalue += 4; size -= 4;
	}
	while (size) {
		*bvalue = readb_(bsrc);
		bsrc++; bvalue++; size--;
	}
}

static void ich_set_bbar(uint32_t minaddr)
{
	const uint32_t bbar_mask = 0x00ffff00;
	uint32_t ichspi_bbar;

	minaddr &= bbar_mask;
	ichspi_bbar = readl_(cntlr.bbar) & ~bbar_mask;
	ichspi_bbar |= minaddr;
	writel_(ichspi_bbar, cntlr.bbar);
}

int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
	puts("spi_cs_is_valid used but not implemented\n");
	return 0;
}

struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
		unsigned int max_hz, unsigned int mode)
{
	ich_spi_slave *slave = malloc(sizeof(*slave));

	if (!slave) {
		puts("ICH SPI: Bad allocation\n");
		return NULL;
	}

	memset(slave, 0, sizeof(*slave));

	slave->bus = bus;
	slave->cs = cs;
	return slave;
}

void spi_free_slave(struct spi_slave *_slave)
{
	ich_spi_slave *slave = (ich_spi_slave *)_slave;
	free(slave);
}

/*
 * Check if this device ID matches one of supported Intel PCH devices.
 *
 * Return the ICH version if there is a match, or zero otherwise.
 */
static inline int get_ich_version(uint16_t device_id)
{
	if (device_id == PCI_DEVICE_ID_INTEL_TGP_LPC)
		return 7;

	if ((device_id >= PCI_DEVICE_ID_INTEL_COUGARPOINT_LPC_MIN &&
	     device_id <= PCI_DEVICE_ID_INTEL_COUGARPOINT_LPC_MAX) ||
	    (device_id >= PCI_DEVICE_ID_INTEL_PANTHERPOINT_LPC_MIN &&
	     device_id <= PCI_DEVICE_ID_INTEL_PANTHERPOINT_LPC_MAX))
		return 9;

	return 0;
}

void spi_init(void)
{
	int ich_version = 0;

	uint8_t *rcrb; /* Root Complex Register Block */
	uint32_t rcba; /* Root Complex Base Address */
	uint8_t bios_cntl;
	pci_dev_t dev;

	int bus;
	int last_bus = pci_last_busno();

	if (last_bus == -1) {
		puts("No PCI busses?\n");
		return;
	}

	for (bus = 0; (bus <= last_bus) && !ich_version; bus++) {
		uint32_t ids;
		uint16_t vendor_id, device_id;

		dev = PCI_BDF(bus, 31, 0);
		pci_read_config_dword(dev, 0, &ids);
		vendor_id = ids;
		device_id = (ids >> 16);

		if (vendor_id != PCI_VENDOR_ID_INTEL)
			continue;

		ich_version = get_ich_version(device_id);
	}

	if (!ich_version) {
		puts("ICH SPI: No ICH found.\n");
		return;
	}

	pci_read_config_dword(dev, 0xf0, &rcba);
	/* Bits 31-14 are the base address, 13-1 are reserved, 0 is enable. */
	rcrb = (uint8_t *)(rcba & 0xffffc000);
	switch (ich_version) {
	case 7:
		{
			const uint16_t ich7_spibar_offset = 0x3020;
			ich7_spi_regs *ich7_spi =
				(ich7_spi_regs *)(rcrb + ich7_spibar_offset);

			ichspi_lock = readw_(&ich7_spi->spis) & SPIS_LOCK;
			cntlr.opmenu = ich7_spi->opmenu;
			cntlr.menubytes = sizeof(ich7_spi->opmenu);
			cntlr.optype = &ich7_spi->optype;
			cntlr.addr = &ich7_spi->spia;
			cntlr.data = (uint8_t *)ich7_spi->spid;
			cntlr.databytes = sizeof(ich7_spi->spid);
			cntlr.status = (uint8_t *)&ich7_spi->spis;
			cntlr.control = &ich7_spi->spic;
			cntlr.bbar = &ich7_spi->bbar;
			cntlr.preop = &ich7_spi->preop;
			break;
		}
	case 9:
		{
			const uint16_t ich9_spibar_offset = 0x3800;
			ich9_spi_regs *ich9_spi =
				(ich9_spi_regs *)(rcrb + ich9_spibar_offset);
			ichspi_lock = readw_(&ich9_spi->hsfs) & HSFS_FLOCKDN;
			cntlr.opmenu = ich9_spi->opmenu;
			cntlr.menubytes = sizeof(ich9_spi->opmenu);
			cntlr.optype = &ich9_spi->optype;
			cntlr.addr = &ich9_spi->faddr;
			cntlr.data = (uint8_t *)ich9_spi->fdata;
			cntlr.databytes = sizeof(ich9_spi->fdata);
			cntlr.status = &ich9_spi->ssfs;
			cntlr.control = (uint16_t *)ich9_spi->ssfc;
			cntlr.bbar = &ich9_spi->bbar;
			cntlr.preop = &ich9_spi->preop;
			break;
		}
	default:
		printf("ICH SPI: Unrecognized ICH version %d.\n", ich_version);
	}

	ich_set_bbar(0);

	/* Disable the BIOS write protect so write commands are allowed. */
	pci_read_config_byte(dev, 0xdc, &bios_cntl);
	switch (ich_version) {
	case 9:
		/* Deassert SMM BIOS Write Protect Disable. */
		bios_cntl &= ~(1 << 5);
		break;

	default:
		break;
	}
	pci_write_config_byte(dev, 0xdc, bios_cntl | 0x1);
}

int spi_claim_bus(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
	return 0;
}

void spi_release_bus(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
}

void spi_cs_activate(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
}

void spi_cs_deactivate(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
}

typedef struct spi_transaction {
	const uint8_t *out;
	uint32_t bytesout;
	uint8_t *in;
	uint32_t bytesin;
	uint8_t type;
	uint8_t opcode;
	uint32_t offset;
} spi_transaction;

static inline void spi_use_out(spi_transaction *trans, unsigned bytes)
{
	trans->out += bytes;
	trans->bytesout -= bytes;
}

static inline void spi_use_in(spi_transaction *trans, unsigned bytes)
{
	trans->in += bytes;
	trans->bytesin -= bytes;
}

static void spi_setup_type(spi_transaction *trans)
{
	trans->type = 0xFF;

	/* Try to guess spi type from read/write sizes. */
	if (trans->bytesin == 0) {
		if (trans->bytesout > 4)
			/*
			 * If bytesin = 0 and bytesout > 4, we presume this is
			 * a write data operation, which is accompanied by an
			 * address.
			 */
			trans->type = SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS;
		else
			trans->type = SPI_OPCODE_TYPE_WRITE_NO_ADDRESS;
		return;
	}

	if (trans->bytesout == 1) { /* and bytesin is > 0 */
		trans->type = SPI_OPCODE_TYPE_READ_NO_ADDRESS;
		return;
	}

	if (trans->bytesout == 4) { /* and bytesin is > 0 */
		trans->type = SPI_OPCODE_TYPE_READ_WITH_ADDRESS;
	}
}

static int spi_setup_opcode(spi_transaction *trans)
{
	uint16_t optypes;
	uint8_t opmenu[cntlr.menubytes];

	trans->opcode = trans->out[0];
	spi_use_out(trans, 1);
	if (!ichspi_lock) {
		/* The lock is off, so just use index 0. */
		writeb_(trans->opcode, cntlr.opmenu);
		optypes = readw_(cntlr.optype);
		optypes = (optypes & 0xfffc) | (trans->type & 0x3);
		writew_(optypes, cntlr.optype);
		return 0;
	} else {
		/* The lock is on. See if what we need is on the menu. */
		uint8_t optype;
		uint16_t opcode_index;

		read_reg(cntlr.opmenu, opmenu, sizeof(opmenu));
		for (opcode_index = 0; opcode_index < cntlr.menubytes;
				opcode_index++) {
			if (opmenu[opcode_index] == trans->opcode)
				break;
		}

		if (opcode_index == cntlr.menubytes) {
			printf("ICH SPI: Opcode %x not found\n",
				trans->opcode);
			return -1;
		}

		optypes = readw_(cntlr.optype);
		optype = (optypes >> (opcode_index * 2)) & 0x3;
		if (trans->type == SPI_OPCODE_TYPE_WRITE_NO_ADDRESS &&
			optype == SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS &&
			trans->bytesout >= 3) {
			/* We guessed wrong earlier. Fix it up. */
			trans->type = optype;
		}
		if (optype != trans->type) {
			printf("ICH SPI: Transaction doesn't fit type %d\n",
				optype);
			return -1;
		}
		return opcode_index;
	}
}

static int spi_setup_offset(spi_transaction *trans)
{
	/* Separate the SPI address and data. */
	switch (trans->type) {
	case SPI_OPCODE_TYPE_READ_NO_ADDRESS:
	case SPI_OPCODE_TYPE_WRITE_NO_ADDRESS:
		return 0;
	case SPI_OPCODE_TYPE_READ_WITH_ADDRESS:
	case SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS:
		trans->offset = ((uint32_t)trans->out[0] << 16) |
				((uint32_t)trans->out[1] << 8) |
				((uint32_t)trans->out[2] << 0);
		spi_use_out(trans, 3);
		return 1;
	default:
		printf("Unrecognized SPI transaction type %#x\n", trans->type);
		return -1;
	}
}

/*
 * Wait for up to 60ms til status register bit(s) turn 1 (in case wait_til_set
 * below is True) or 0. In case the wait was for the bit(s) to set - write
 * those bits back, which would cause resetting them.
 *
 * Return the last read status value on success or -1 on failure.
 */
static int ich_status_poll(u16 bitmask, int wait_til_set)
{
	int timeout = 6000; /* This will result in 60 ms */
	u16 status = 0;

	while (timeout--) {
		status = readw_(cntlr.status);
		if (wait_til_set ^ ((status & bitmask) == 0)) {
			if (wait_til_set)
				writew_((status & bitmask), cntlr.status);
			return status;
		}
		udelay(10);
	}

	printf("ICH SPI: SCIP timeout, read %x, expected %x\n",
		status, bitmask);
	return -1;
}

int spi_xfer(struct spi_slave *slave, const void *dout,
		unsigned int bitsout, void *din, unsigned int bitsin)
{
	uint16_t control;
	int16_t opcode_index;
	int with_address;
	int status;

	spi_transaction trans = {
		dout, bitsout / 8,
		din, bitsin / 8,
		0xff, 0xff, 0
	};

	/* There has to always at least be an opcode. */
	if (!bitsout || !dout) {
		puts("ICH SPI: No opcode for transfer\n");
		return -1;
	}
	/* Make sure if we read something we have a place to put it. */
	if (bitsin != 0 && !din) {
		puts("ICH SPI: Read but no target buffer\n");
		return -1;
	}
	/* Right now we don't support writing partial bytes. */
	if (bitsout % 8 || bitsin % 8) {
		puts("ICH SPI: Accessing partial bytes not supported\n");
		return -1;
	}

	if (ich_status_poll(SPIS_SCIP, 0) == -1)
		return -1;

	writew_(SPIS_CDS | SPIS_FCERR, cntlr.status);

	spi_setup_type(&trans);
	if ((opcode_index = spi_setup_opcode(&trans)) < 0)
		return -1;
	if ((with_address = spi_setup_offset(&trans)) < 0)
		return -1;

	if (!ichspi_lock && trans.opcode == 0x06) {
		/*
		 * Treat Write Enable as Atomic Pre-Op if possible
		 * in order to prevent the Management Engine from
		 * issuing a transaction between WREN and DATA.
		 */
		writew_(trans.opcode, cntlr.preop);
		return 0;
	}

	/* Preset control fields */
	control = SPIC_SCGO | ((opcode_index & 0x07) << 4);

	/* Issue atomic preop cycle if needed */
	if (readw_(cntlr.preop))
		control |= SPIC_ACS;

	if (!trans.bytesout && !trans.bytesin) {
		/*
		 * This is a 'no data' command (like Write Enable), its
		 * bitesout size was 1, decremented to zero while executing
		 * spi_setup_opcode() above. Tell the chip to send the
		 * command.
		 */
		writew_(control, cntlr.control);

		/* wait for the result */
		status = ich_status_poll(SPIS_CDS | SPIS_FCERR, 1);
		if (status == -1)
			return -1;

		if (status & SPIS_FCERR) {
			puts("ICH SPI: Command transaction error\n");
			return -1;
		}

		return 0;
	}

	/*
	 * Check if this is a write command atempting to transfer more bytes
	 * than the controller can handle. Iterations for writes are not
	 * supported here because each SPI write command needs to be preceded
	 * and followed by other SPI commands, and this sequence is controlled
	 * by the SPI chip driver.
	 */
	if (trans.bytesout > cntlr.databytes) {
		puts("ICH SPI: Too much to write. Does your SPI chip driver use"
		     " CONTROLLER_PAGE_LIMIT?\n");
		return -1;
	}

	/*
	 * Read or write up to databytes bytes at a time until everything has
	 * been sent.
	 */
	while (trans.bytesout || trans.bytesin) {
		uint32_t data_length;

		/* SPI addresses are 24 bit only */
		writel_(trans.offset & 0x00FFFFFF, cntlr.addr);

		if (trans.bytesout)
			data_length = min(trans.bytesout, cntlr.databytes);
		else
			data_length = min(trans.bytesin, cntlr.databytes);

		/* Program data into FDATA0 to N */
		if (trans.bytesout) {
			write_reg(trans.out, cntlr.data, data_length);
			spi_use_out(&trans, data_length);
			if (with_address)
				trans.offset += data_length;
		}

		/* Add proper control fields' values */
		control &= ~((cntlr.databytes - 1) << 8);
		control |= SPIC_DS;
		control |= (data_length - 1) << 8;

		/* write it */
		writew_(control, cntlr.control);

		/* Wait for Cycle Done Status or Flash Cycle Error. */
		status = ich_status_poll(SPIS_CDS | SPIS_FCERR, 1);
		if (status == -1)
			return -1;

		if (status & SPIS_FCERR) {
			puts("ICH SPI: Data transaction error\n");
			return -1;
		}

		if (trans.bytesin) {
			read_reg(cntlr.data, trans.in, data_length);
			spi_use_in(&trans, data_length);
			if (with_address)
				trans.offset += data_length;
		}
	}

	/* Clear atomic preop now that xfer is done */
	writew_(0, cntlr.preop);

	return 0;
}