#include <device/pci_def.h>
#include <device/pci_ids.h>
#include <device/hypertransport_def.h>

static unsigned ht_lookup_slave_capability(device_t dev)
{
	unsigned pos;
	uint8_t hdr_type;

	hdr_type = pci_read_config8(dev, PCI_HEADER_TYPE);
	pos = 0;
	hdr_type &= 0x7f;

	if ((hdr_type == PCI_HEADER_TYPE_NORMAL) ||
		(hdr_type == PCI_HEADER_TYPE_BRIDGE)) {
		pos = PCI_CAPABILITY_LIST;
	}
	if (pos > PCI_CAP_LIST_NEXT) {
		pos = pci_read_config8(dev, pos);
	}
	while(pos != 0) { /* loop through the linked list */
		uint8_t cap;
		cap = pci_read_config8(dev, pos + PCI_CAP_LIST_ID);
		if (cap == PCI_CAP_ID_HT) {
			uint16_t flags;

			flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
			if ((flags >> 13) == 0) {
				/* Entry is a Slave secondary, success... */
				break;
			}
		}
		pos = pci_read_config8(dev, pos + PCI_CAP_LIST_NEXT);
	}
	return pos;
}

static void ht_collapse_previous_enumeration(unsigned bus)
{
	device_t dev;
	
	/* Spin through the devices and collapse any previous
	 * hypertransport enumeration.
	 */
	for(dev = PCI_DEV(bus, 0, 0); dev <= PCI_DEV(bus, 0x1f, 0x7); dev += PCI_DEV(0, 1, 0)) {
		uint32_t id;
		unsigned pos, flags;
		
		id = pci_read_config32(dev, PCI_VENDOR_ID);
		if ((id == 0xffffffff) || (id == 0x00000000) ||
			(id == 0x0000ffff) || (id == 0xffff0000)) {
			continue;
		}
		pos = ht_lookup_slave_capability(dev);
		if (!pos) {
			continue;
		}
		
		/* Clear the unitid */
		flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
		flags &= ~0x1f;
		pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);
	}
}


static unsigned ht_read_freq_cap(device_t dev, unsigned pos)
{
	/* Handle bugs in valid hypertransport frequency reporting */
	unsigned freq_cap;
	uint32_t id;

	freq_cap = pci_read_config16(dev, pos);
	freq_cap &= ~(1 << HT_FREQ_VENDOR); /* Ignore Vendor HT frequencies */

	id = pci_read_config32(dev, 0);

	/* AMD 8131 Errata 48 */
	if (id == (PCI_VENDOR_ID_AMD | (PCI_DEVICE_ID_AMD_8131_PCIX << 16))) {
		freq_cap &= ~(1 << HT_FREQ_800Mhz);
	}
	/* AMD 8151 Errata 23 */
	if (id == (PCI_VENDOR_ID_AMD | (PCI_DEVICE_ID_AMD_8151_SYSCTRL << 16))) {
		freq_cap &= ~(1 << HT_FREQ_800Mhz);
	}
	/* AMD K8 Unsupported 1Ghz? */
	if (id == (PCI_VENDOR_ID_AMD | (0x1100 << 16))) {
		freq_cap &= ~(1 << HT_FREQ_1000Mhz);
	}
	return freq_cap;
}

#define LINK_OFFS(WIDTH,FREQ,FREQ_CAP) \
	(((WIDTH & 0xff) << 16) | ((FREQ & 0xff) << 8) | (FREQ_CAP & 0xFF))

#define LINK_WIDTH(OFFS)    ((OFFS >> 16) & 0xFF)
#define LINK_FREQ(OFFS)     ((OFFS >> 8) & 0xFF)
#define LINK_FREQ_CAP(OFFS) ((OFFS) & 0xFF)

#define PCI_HT_HOST_OFFS LINK_OFFS( \
	PCI_HT_CAP_HOST_WIDTH, \
	PCI_HT_CAP_HOST_FREQ, \
	PCI_HT_CAP_HOST_FREQ_CAP)

#define PCI_HT_SLAVE0_OFFS LINK_OFFS( \
	PCI_HT_CAP_SLAVE_WIDTH0, \
	PCI_HT_CAP_SLAVE_FREQ0, \
	PCI_HT_CAP_SLAVE_FREQ_CAP0)

#define PCI_HT_SLAVE1_OFFS LINK_OFFS( \
	PCI_HT_CAP_SLAVE_WIDTH1, \
	PCI_HT_CAP_SLAVE_FREQ1, \
	PCI_HT_CAP_SLAVE_FREQ_CAP1)

static int ht_optimize_link(
	device_t dev1, uint8_t pos1, unsigned offs1,
	device_t dev2, uint8_t pos2, unsigned offs2)
{
	static const uint8_t link_width_to_pow2[]= { 3, 4, 0, 5, 1, 2, 0, 0 };
	static const uint8_t pow2_to_link_width[] = { 0x7, 4, 5, 0, 1, 3 };
	uint16_t freq_cap1, freq_cap2, freq_cap, freq_mask;
	uint8_t width_cap1, width_cap2, width_cap, width, old_width, ln_width1, ln_width2;
	uint8_t freq, old_freq;
	int needs_reset;
	/* Set link width and frequency */

	/* Initially assume everything is already optimized and I don't need a reset */
	needs_reset = 0;

	/* Get the frequency capabilities */
	freq_cap1 = ht_read_freq_cap(dev1, pos1 + LINK_FREQ_CAP(offs1));
	freq_cap2 = ht_read_freq_cap(dev2, pos2 + LINK_FREQ_CAP(offs2));

	/* Calculate the highest possible frequency */
	freq = log2(freq_cap1 & freq_cap2);

	/* See if I am changing the link freqency */
	old_freq = pci_read_config8(dev1, pos1 + LINK_FREQ(offs1));
	needs_reset |= old_freq != freq;
	old_freq = pci_read_config8(dev2, pos2 + LINK_FREQ(offs2));
	needs_reset |= old_freq != freq;

	/* Set the Calulcated link frequency */
	pci_write_config8(dev1, pos1 + LINK_FREQ(offs1), freq);
	pci_write_config8(dev2, pos2 + LINK_FREQ(offs2), freq);

	/* Get the width capabilities */
	width_cap1 = pci_read_config8(dev1, pos1 + LINK_WIDTH(offs1));
	width_cap2 = pci_read_config8(dev2, pos2 + LINK_WIDTH(offs2));

	/* Calculate dev1's input width */
	ln_width1 = link_width_to_pow2[width_cap1 & 7];
	ln_width2 = link_width_to_pow2[(width_cap2 >> 4) & 7];
	if (ln_width1 > ln_width2) {
		ln_width1 = ln_width2;
	}
	width = pow2_to_link_width[ln_width1];
	/* Calculate dev1's output width */
	ln_width1 = link_width_to_pow2[(width_cap1 >> 4) & 7];
	ln_width2 = link_width_to_pow2[width_cap2 & 7];
	if (ln_width1 > ln_width2) {
		ln_width1 = ln_width2;
	}
	width |= pow2_to_link_width[ln_width1] << 4;

	/* See if I am changing dev1's width */
	old_width = pci_read_config8(dev1, pos1 + LINK_WIDTH(offs1) + 1);
	needs_reset |= old_width != width;

	/* Set dev1's widths */
	pci_write_config8(dev1, pos1 + LINK_WIDTH(offs1) + 1, width);

	/* Calculate dev2's width */
	width = ((width & 0x70) >> 4) | ((width & 0x7) << 4);

	/* See if I am changing dev2's width */
	old_width = pci_read_config8(dev2, pos2 + LINK_WIDTH(offs2) + 1);
	needs_reset |= old_width != width;

	/* Set dev2's widths */
	pci_write_config8(dev2, pos2 + LINK_WIDTH(offs2) + 1, width);

	return needs_reset;
}

static int ht_setup_chain(device_t udev, unsigned upos)
{
	/* Assumption the HT chain that is bus 0 has the HT I/O Hub on it.
	 * On most boards this just happens.  If a cpu has multiple
	 * non Coherent links the appropriate bus registers for the
	 * links needs to be programed to point at bus 0.
	 */
	unsigned next_unitid, last_unitid;
	int reset_needed;
	unsigned uoffs;

#warning "FIXME handle multiple chains!"

	/* Make certain the HT bus is not enumerated */
	ht_collapse_previous_enumeration(0);

	reset_needed = 0;
	uoffs = PCI_HT_HOST_OFFS;
	next_unitid = 1;
	do {
		uint32_t id;
		uint8_t pos;
		unsigned flags, count;
		device_t dev = PCI_DEV(0, 0, 0);
		last_unitid = next_unitid;

		id = pci_read_config32(dev, PCI_VENDOR_ID);
		/* If the chain is enumerated quit */
		if (((id & 0xffff) == 0x0000) || ((id & 0xffff) == 0xffff) ||
			(((id >> 16) & 0xffff) == 0xffff) ||
			(((id >> 16) & 0xffff) == 0x0000)) {
			break;
		}
		pos = ht_lookup_slave_capability(dev);
		if (!pos) {
			print_err("HT link capability not found\r\n");
			break;
		}
		/* Setup the Hypertransport link */
		reset_needed |= ht_optimize_link(udev, upos, uoffs, dev, pos, PCI_HT_SLAVE0_OFFS);

		/* Update the Unitid of the current device */
		flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
		flags &= ~0x1f; /* mask out the bse Unit ID */
		flags |= next_unitid & 0x1f;
		pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);

		/* Remeber the location of the last device */
		udev = PCI_DEV(0, next_unitid, 0);
		upos = pos;
		uoffs = PCI_HT_SLAVE1_OFFS;

		/* Compute the number of unitids consumed */
		count = (flags >> 5) & 0x1f;
		next_unitid += count;

	} while((last_unitid != next_unitid) && (next_unitid <= 0x1f));
	return reset_needed;
}
struct ht_chain {
        device_t udev;
        unsigned upos;
        unsigned devreg; 
        unsigned mindev; 
};              

static int ht_setup_chains(const struct ht_chain *ht_c, int ht_c_num)
{               
        /* Assumption the HT chain that is bus 0 has the HT I/O Hub on it. 
         * On most boards this just happens.  If a cpu has multiple
         * non Coherent links the appropriate bus registers for the
         * links needs to be programed to point at bus 0.
         */     
        unsigned next_unitid, last_unitid;
        int reset_needed; 
        unsigned uoffs;
        unsigned upos;
        device_t udev;
        int i;

        /* Make certain the HT bus is not enumerated */
        ht_collapse_previous_enumeration(0);

        reset_needed = 0;
        next_unitid = 1;


        for(i=0;i<ht_c_num;i++) {
#if 0
        unsigned tmp;
        tmp = pci_read_config8(PCI_DEV(0,0x18,1),ht_c[i].devreg);
#endif

        pci_write_config8(PCI_DEV(0,0x18,1), ht_c[i].devreg, 0);
#if CONFIG_MAX_CPUS > 1 
        pci_write_config8(PCI_DEV(0,0x19,1), ht_c[i].devreg, 0);
#endif
#if CONFIG_MAX_CPUS > 2
        pci_write_config8(PCI_DEV(0,0x1a,1), ht_c[i].devreg, 0);
        pci_write_config8(PCI_DEV(0,0x1b,1), ht_c[i].devreg, 0);
#endif

        uoffs = PCI_HT_HOST_OFFS;
        upos = ht_c[i].upos;
        udev = ht_c[i].udev;
        do {
                uint32_t id;
                uint8_t pos;
                unsigned flags, count;
                device_t dev = PCI_DEV(0, 0, 0);
                last_unitid = next_unitid;
                
                id = pci_read_config32(dev, PCI_VENDOR_ID);
                /* If the chain is enumerated quit */
                if (((id & 0xffff) == 0x0000) || ((id & 0xffff) == 0xffff) ||
                        (((id >> 16) & 0xffff) == 0xffff) ||
                        (((id >> 16) & 0xffff) == 0x0000)) {
                        break;
                }       
                pos = ht_lookup_slave_capability(dev);
                if (!pos) {
                        print_err("HT link capability not found\r\n");
                        break;
                }
                /* Setup the Hypertransport link */
                reset_needed |= ht_optimize_link(udev, upos, uoffs, dev, pos, PCI_HT_SLAVE0_OFFS);

                /* Update the Unitid of the current device */
                flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
                flags &= ~0x1f; /* mask out the bse Unit ID */
                flags |= next_unitid & 0x1f;
                pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);

                /* Remeber the location of the last device */
                udev = PCI_DEV(0, next_unitid, 0);
                upos = pos;
                uoffs = PCI_HT_SLAVE1_OFFS;

                /* Compute the number of unitids consumed */
                count = (flags >> 5) & 0x1f;
                next_unitid += count;

        } while((last_unitid != next_unitid) && (next_unitid <= 0x1f));
#if 0
        pci_write_config8(PCI_DEV(0,0x18,1), ht_c[i].devreg, tmp);
#if CONFIG_MAX_CPUS > 1 
        pci_write_config8(PCI_DEV(0,0x19,1), ht_c[i].devreg, tmp);
#endif
#if CONFIG_MAX_CPUS > 2
        pci_write_config8(PCI_DEV(0,0x1a,1), ht_c[i].devreg, tmp);
        pci_write_config8(PCI_DEV(0,0x1b,1), ht_c[i].devreg, tmp);
#endif
#else
        pci_write_config8(PCI_DEV(0,0x18,1), ht_c[i].devreg, ht_c[i].mindev);
#if CONFIG_MAX_CPUS > 1 
        pci_write_config8(PCI_DEV(0,0x19,1), ht_c[i].devreg, ht_c[i].mindev);
#endif
#if CONFIG_MAX_CPUS > 2
        pci_write_config8(PCI_DEV(0,0x1a,1), ht_c[i].devreg, ht_c[i].mindev);
        pci_write_config8(PCI_DEV(0,0x1b,1), ht_c[i].devreg, ht_c[i].mindev);
#endif
#endif

        }

        return reset_needed;
}