/* $Id: pci_iommu.c,v 1.7 1999/12/20 14:08:15 jj Exp $
 * pci_iommu.c: UltraSparc PCI controller IOM/STC support.
 *
 * Copyright (C) 1999 David S. Miller (davem@redhat.com)
 * Copyright (C) 1999 Jakub Jelinek (jakub@redhat.com)
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>

#include <asm/pbm.h>

#include "iommu_common.h"

#define PCI_STC_CTXMATCH_ADDR(STC, CTX)	\
	((STC)->strbuf_ctxmatch_base + ((CTX) << 3))

/* Accessing IOMMU and Streaming Buffer registers.
 * REG parameter is a physical address.  All registers
 * are 64-bits in size.
 */
#define pci_iommu_read(__reg) \
({	u64 __ret; \
	__asm__ __volatile__("ldxa [%1] %2, %0" \
			     : "=r" (__ret) \
			     : "r" (__reg), "i" (ASI_PHYS_BYPASS_EC_E) \
			     : "memory"); \
	__ret; \
})
#define pci_iommu_write(__reg, __val) \
	__asm__ __volatile__("stxa %0, [%1] %2" \
			     : /* no outputs */ \
			     : "r" (__val), "r" (__reg), \
			       "i" (ASI_PHYS_BYPASS_EC_E))

static iopte_t *alloc_streaming_cluster(struct pci_iommu *iommu, unsigned long npages)
{
	iopte_t *iopte;
	unsigned long cnum, ent;

	cnum = 0;
	while ((1UL << cnum) < npages)
		cnum++;
	iopte  = iommu->page_table + (cnum << (iommu->page_table_sz_bits - PBM_LOGCLUSTERS));
	iopte += ((ent = iommu->lowest_free[cnum]) << cnum);

	if (iopte_val(iopte[(1UL << cnum)]) == 0UL) {
		/* Fast path. */
		iommu->lowest_free[cnum] = ent + 1;
	} else {
		unsigned long pte_off = 1;

		ent += 1;
		do {
			pte_off++;
			ent++;
		} while (iopte_val(iopte[(pte_off << cnum)]) != 0UL);
		iommu->lowest_free[cnum] = ent;
	}

	/* I've got your streaming cluster right here buddy boy... */
	return iopte;
}

static inline void free_streaming_cluster(struct pci_iommu *iommu, u32 base, unsigned long npages)
{
	unsigned long cnum, ent;

	cnum = 0;
	while ((1UL << cnum) < npages)
		cnum++;
	ent = (base << (32 - PAGE_SHIFT + PBM_LOGCLUSTERS - iommu->page_table_sz_bits))
		>> (32 + PBM_LOGCLUSTERS + cnum - iommu->page_table_sz_bits);
	if (ent < iommu->lowest_free[cnum])
		iommu->lowest_free[cnum] = ent;
}

/* We allocate consistant mappings from the end of cluster zero. */
static iopte_t *alloc_consistant_cluster(struct pci_iommu *iommu, unsigned long npages)
{
	iopte_t *iopte;

	iopte = iommu->page_table + (1 << (iommu->page_table_sz_bits - PBM_LOGCLUSTERS));
	while (iopte > iommu->page_table) {
		iopte--;
		if (!(iopte_val(*iopte) & IOPTE_VALID)) {
			unsigned long tmp = npages;

			while (--tmp) {
				iopte--;
				if (iopte_val(*iopte) & IOPTE_VALID)
					break;
			}
			if (tmp == 0)
				return iopte;
		}
	}
	return NULL;
}

#define IOPTE_CONSISTANT(CTX, PADDR) \
	(IOPTE_VALID | IOPTE_CACHE | IOPTE_WRITE | \
	 (((CTX) << 47) & IOPTE_CONTEXT) | \
	 ((PADDR) & IOPTE_PAGE))

#define IOPTE_STREAMING(CTX, PADDR) \
	(IOPTE_CONSISTANT(CTX, PADDR) | IOPTE_STBUF)

#define IOPTE_INVALID	0UL

/* Allocate and map kernel buffer of size SIZE using consistant mode
 * DMA for PCI device PDEV.  Return non-NULL cpu-side address if
 * successful and set *DMA_ADDRP to the PCI side dma address.
 */
void *pci_alloc_consistant(struct pci_dev *pdev, long size, u32 *dma_addrp)
{
	struct pcidev_cookie *pcp;
	struct pci_iommu *iommu;
	iopte_t *iopte;
	unsigned long flags, order, first_page, ctx;
	void *ret;
	int npages;

	if (size <= 0 || pdev == NULL ||
	    pdev->sysdata == NULL || dma_addrp == NULL)
		return NULL;

	size = PAGE_ALIGN(size);
	for (order = 0; order < 10; order++) {
		if ((PAGE_SIZE << order) >= size)
			break;
	}
	if (order == 10)
		return NULL;

	first_page = __get_free_pages(GFP_ATOMIC, order);
	if (first_page == 0UL)
		return NULL;
	memset((char *)first_page, 0, PAGE_SIZE << order);

	pcp = pdev->sysdata;
	iommu = &pcp->pbm->parent->iommu;

	spin_lock_irqsave(&iommu->lock, flags);
	iopte = alloc_consistant_cluster(iommu, size >> PAGE_SHIFT);
	if (iopte == NULL) {
		spin_unlock_irqrestore(&iommu->lock, flags);
		free_pages(first_page, order);
		return NULL;
	}

	*dma_addrp = (iommu->page_table_map_base +
		      ((iopte - iommu->page_table) << PAGE_SHIFT));
	ret = (void *) first_page;
	npages = size >> PAGE_SHIFT;
	ctx = 0;
	if (iommu->iommu_ctxflush)
		ctx = iommu->iommu_cur_ctx++;
	first_page = __pa(first_page);
	while (npages--) {
		iopte_val(*iopte) = IOPTE_CONSISTANT(ctx, first_page);
		iopte++;
		first_page += PAGE_SIZE;
	}

	if (iommu->iommu_ctxflush) {
		pci_iommu_write(iommu->iommu_ctxflush, ctx);
	} else {
		int i;
		u32 daddr = *dma_addrp;

		npages = size >> PAGE_SHIFT;
		for (i = 0; i < npages; i++) {
			pci_iommu_write(iommu->iommu_flush, daddr);
			daddr += PAGE_SIZE;
		}
	}

	spin_unlock_irqrestore(&iommu->lock, flags);

	return ret;
}

/* Free and unmap a consistant DMA translation. */
void pci_free_consistant(struct pci_dev *pdev, long size, void *cpu, u32 dvma)
{
	struct pcidev_cookie *pcp;
	struct pci_iommu *iommu;
	iopte_t *iopte;
	unsigned long flags, order, npages, i;

	if (size <= 0 || pdev == NULL ||
	    pdev->sysdata == NULL || cpu == NULL)
		return;

	npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
	pcp = pdev->sysdata;
	iommu = &pcp->pbm->parent->iommu;
	iopte = iommu->page_table +
		((dvma - iommu->page_table_map_base) >> PAGE_SHIFT);

	spin_lock_irqsave(&iommu->lock, flags);

	/* Data for consistant mappings cannot enter the streaming
	 * buffers, so we only need to update the TSB.  Flush of the
	 * IOTLB is done later when these ioptes are used for a new
	 * allocation.
	 */

	for (i = 0; i < npages; i++, iopte++)
		iopte_val(*iopte) = IOPTE_INVALID;

	spin_unlock_irqrestore(&iommu->lock, flags);

	for (order = 0; order < 10; order++) {
		if ((PAGE_SIZE << order) >= size)
			break;
	}
	if (order < 10)
		free_pages((unsigned long)cpu, order);
}

/* Map a single buffer at PTR of SZ bytes for PCI DMA
 * in streaming mode.
 */
u32 pci_map_single(struct pci_dev *pdev, void *ptr, long sz)
{
	struct pcidev_cookie *pcp = pdev->sysdata;
	struct pci_iommu *iommu = &pcp->pbm->parent->iommu;
	struct pci_strbuf *strbuf = &pcp->pbm->stc;
	iopte_t *base;
	unsigned long flags, npages, oaddr;
	unsigned long i, base_paddr, ctx;
	u32 bus_addr, ret;

	oaddr = (unsigned long)ptr;
	npages = PAGE_ALIGN(oaddr + sz) - (oaddr & PAGE_MASK);
	npages >>= PAGE_SHIFT;

	spin_lock_irqsave(&iommu->lock, flags);

	base = alloc_streaming_cluster(iommu, npages);
	bus_addr = (iommu->page_table_map_base +
		    ((base - iommu->page_table) << PAGE_SHIFT));
	ret = bus_addr | (oaddr & ~PAGE_MASK);
	base_paddr = __pa(oaddr & PAGE_MASK);
	ctx = 0;
	if (iommu->iommu_ctxflush)
		ctx = iommu->iommu_cur_ctx++;
	if (strbuf->strbuf_enabled) {
		for (i = 0; i < npages; i++, base++, base_paddr += PAGE_SIZE)
			iopte_val(*base) = IOPTE_STREAMING(ctx, base_paddr);
	} else {
		for (i = 0; i < npages; i++, base++, base_paddr += PAGE_SIZE)
			iopte_val(*base) = IOPTE_CONSISTANT(ctx, base_paddr);
	}

	/* Flush the IOMMU TLB. */
	if (iommu->iommu_ctxflush) {
		pci_iommu_write(iommu->iommu_ctxflush, ctx);
	} else {
		for (i = 0; i < npages; i++, bus_addr += PAGE_SIZE)
			pci_iommu_write(iommu->iommu_flush, bus_addr);
	}

	spin_unlock_irqrestore(&iommu->lock, flags);

	return ret;
}

/* Unmap a single streaming mode DMA translation. */
void pci_unmap_single(struct pci_dev *pdev, u32 bus_addr, long sz)
{
	struct pcidev_cookie *pcp = pdev->sysdata;
	struct pci_iommu *iommu = &pcp->pbm->parent->iommu;
	struct pci_strbuf *strbuf = &pcp->pbm->stc;
	iopte_t *base;
	unsigned long flags, npages, i, ctx;

	npages = PAGE_ALIGN(bus_addr + sz) - (bus_addr & PAGE_MASK);
	npages >>= PAGE_SHIFT;
	base = iommu->page_table +
		((bus_addr - iommu->page_table_map_base) >> PAGE_SHIFT);
	bus_addr &= PAGE_MASK;

	spin_lock_irqsave(&iommu->lock, flags);

	/* Step 1: Kick data out of streaming buffers if necessary. */
	if (strbuf->strbuf_enabled) {
		u32 vaddr = bus_addr;

		/* Record the context, if any. */
		ctx = 0;
		if (iommu->iommu_ctxflush)
			ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;

		PCI_STC_FLUSHFLAG_INIT(strbuf);
		if (strbuf->strbuf_ctxflush &&
		    iommu->iommu_ctxflush) {
			unsigned long matchreg, flushreg;

			flushreg = strbuf->strbuf_ctxflush;
			matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
			do {
				pci_iommu_write(flushreg, ctx);
			} while(((long)pci_iommu_read(matchreg)) < 0L);
		} else {
			for (i = 0; i < npages; i++, vaddr += PAGE_SIZE)
				pci_iommu_write(strbuf->strbuf_pflush, vaddr);
		}

		pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
		(void) pci_iommu_read(iommu->write_complete_reg);
		while (!PCI_STC_FLUSHFLAG_SET(strbuf))
			membar("#LoadLoad");
	}

	/* Step 2: Clear out first TSB entry. */
	iopte_val(*base) = IOPTE_INVALID;

	free_streaming_cluster(iommu, bus_addr - iommu->page_table_map_base, npages);

	/* Step 3: Ensure completion of previous PIO writes. */
	(void) pci_iommu_read(iommu->write_complete_reg);

	spin_unlock_irqrestore(&iommu->lock, flags);
}

static inline struct scatterlist *fill_sg(iopte_t *iopte, struct scatterlist *sg, int nents, unsigned long ctx, int streaming)
{
	struct scatterlist *dma_sg = sg;

	do {
		unsigned long pteval = ~0UL;
		u32 dma_npages;

		dma_npages = ((dma_sg->dvma_address & (PAGE_SIZE - 1UL)) +
			      dma_sg->dvma_length +
			      ((u32)(PAGE_SIZE - 1UL))) >> PAGE_SHIFT;
		do {
			unsigned long offset;
			signed int len;

			/* If we are here, we know we have at least one
			 * more page to map.  So walk forward until we
			 * hit a page crossing, and begin creating new
			 * mappings from that spot.
			 */
			for (;;) {
				unsigned long tmp;

				tmp = (unsigned long) __pa(sg->address);
				len = sg->length;
				if (((tmp ^ pteval) >> PAGE_SHIFT) != 0UL) {
					pteval = tmp & PAGE_MASK;
					offset = tmp & (PAGE_SIZE - 1UL);
					break;
				}
				if (((tmp ^ (tmp + len - 1UL)) >> PAGE_SHIFT) != 0UL) {
					pteval = (tmp + PAGE_SIZE) & PAGE_MASK;
					offset = 0UL;
					len -= (PAGE_SIZE - (tmp & (PAGE_SIZE - 1UL)));
					break;
				}
				sg++;
			}

			if (streaming)
				pteval = IOPTE_STREAMING(ctx, pteval);
			else
				pteval = IOPTE_CONSISTANT(ctx, pteval);
			while (len > 0) {
				*iopte++ = __iopte(pteval);
				pteval += PAGE_SIZE;
				len -= (PAGE_SIZE - offset);
				offset = 0;
				dma_npages--;
			}

			pteval = (pteval & IOPTE_PAGE) + len;
			sg++;

			/* Skip over any tail mappings we've fully mapped,
			 * adjusting pteval along the way.  Stop when we
			 * detect a page crossing event.
			 */
			while ((pteval << (64 - PAGE_SHIFT)) != 0UL &&
			       pteval == __pa(sg->address) &&
			       ((pteval ^
				 (__pa(sg->address) + sg->length - 1UL)) >> PAGE_SHIFT) == 0UL) {
				pteval += sg->length;
				sg++;
			}
			if ((pteval << (64 - PAGE_SHIFT)) == 0UL)
				pteval = ~0UL;
		} while (dma_npages != 0);
		dma_sg++;
	} while (dma_sg->dvma_length != 0);
	return dma_sg;
}

/* Map a set of buffers described by SGLIST with NELEMS array
 * elements in streaming mode for PCI DMA.
 * When making changes here, inspect the assembly output. I was having
 * hard time to kepp this routine out of using stack slots for holding variables.
 */
int pci_map_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems)
{
	struct pcidev_cookie *pcp;
	struct pci_iommu *iommu;
	struct pci_strbuf *strbuf;
	unsigned long flags, ctx, i, npages;
	iopte_t *base;
	u32 dma_base;
	struct scatterlist *sgtmp;
	int tmp;

	/* Fast path single entry scatterlists. */
	if (nelems == 1) {
		sglist->dvma_address = pci_map_single(pdev, sglist->address, sglist->length);
		sglist->dvma_length = sglist->length;
		return 1;
	}
                                                                        
	pcp = pdev->sysdata;
	iommu = &pcp->pbm->parent->iommu;
	strbuf = &pcp->pbm->stc;
	
	/* Step 1: Prepare scatter list. */

	npages = prepare_sg(sglist, nelems);

	/* Step 2: Allocate a cluster. */

	spin_lock_irqsave(&iommu->lock, flags);

	base = alloc_streaming_cluster(iommu, npages);
	dma_base = iommu->page_table_map_base + ((base - iommu->page_table) << PAGE_SHIFT);

	/* Step 3: Normalize DMA addresses. */
	tmp = nelems;

	sgtmp = sglist;
	while (tmp-- && sgtmp->dvma_length) {
		sgtmp->dvma_address += dma_base;
		sgtmp++;
	}

	/* Step 4: Choose a context if necessary. */
	ctx = 0;
	if (iommu->iommu_ctxflush)
		ctx = iommu->iommu_cur_ctx++;

	/* Step 5: Create the mappings. */
	sgtmp = fill_sg (base, sglist, nelems, ctx, strbuf->strbuf_enabled);
#ifdef VERIFY_SG
	verify_sglist(sglist, nelems, base, npages);
#endif

	/* Step 6: Flush the IOMMU TLB. */
	if (iommu->iommu_ctxflush) {
		pci_iommu_write(iommu->iommu_ctxflush, ctx);
	} else {
		for (i = 0; i < npages; i++, dma_base += PAGE_SIZE)
			pci_iommu_write(iommu->iommu_flush, dma_base);
	}

	spin_unlock_irqrestore(&iommu->lock, flags);

	return sgtmp - sglist;
}

/* Unmap a set of streaming mode DMA translations. */
void pci_unmap_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems)
{
	struct pcidev_cookie *pcp = pdev->sysdata;
	struct pci_iommu *iommu = &pcp->pbm->parent->iommu;
	struct pci_strbuf *strbuf = &pcp->pbm->stc;
	iopte_t *base;
	unsigned long flags, ctx, i, npages;
	u32 bus_addr;
	
	bus_addr = sglist->dvma_address & PAGE_MASK;

	i = 0;
	if (nelems > 1) {
		for (; i < nelems; i++)
			if (sglist[i].dvma_length == 0)
				break;
		i--;
	}
	npages = (PAGE_ALIGN(sglist[i].dvma_address + sglist[i].dvma_length) - bus_addr) >> PAGE_SHIFT;

	base = iommu->page_table +
		((bus_addr - iommu->page_table_map_base) >> PAGE_SHIFT);

	spin_lock_irqsave(&iommu->lock, flags);

	/* Step 1: Kick data out of streaming buffers if necessary. */
	if (strbuf->strbuf_enabled) {
		u32 vaddr = bus_addr;

		/* Record the context, if any. */
		ctx = 0;
		if (iommu->iommu_ctxflush)
			ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;

		PCI_STC_FLUSHFLAG_INIT(strbuf);
		if (strbuf->strbuf_ctxflush &&
		    iommu->iommu_ctxflush) {
			unsigned long matchreg, flushreg;

			flushreg = strbuf->strbuf_ctxflush;
			matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
			do {
				pci_iommu_write(flushreg, ctx);
			} while(((long)pci_iommu_read(matchreg)) < 0L);
		} else {
			for (i = 0; i < npages; i++, vaddr += PAGE_SIZE)
				pci_iommu_write(strbuf->strbuf_pflush, vaddr);
		}

		pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
		(void) pci_iommu_read(iommu->write_complete_reg);
		while (!PCI_STC_FLUSHFLAG_SET(strbuf))
			membar("#LoadLoad");
	}

	/* Step 2: Clear out first TSB entry. */
	iopte_val(*base) = IOPTE_INVALID;

	free_streaming_cluster(iommu, bus_addr - iommu->page_table_map_base, npages);

	/* Step 3: Ensure completion of previous PIO writes. */
	(void) pci_iommu_read(iommu->write_complete_reg);

	spin_unlock_irqrestore(&iommu->lock, flags);
}

/* Make physical memory consistant for a single
 * streaming mode DMA translation after a transfer.
 */
void pci_dma_sync_single(struct pci_dev *pdev, u32 bus_addr, long sz)
{
	struct pcidev_cookie *pcp = pdev->sysdata;
	struct pci_iommu *iommu = &pcp->pbm->parent->iommu;
	struct pci_strbuf *strbuf = &pcp->pbm->stc;
	unsigned long flags, ctx, npages;

	if (!strbuf->strbuf_enabled)
		return;

	spin_lock_irqsave(&iommu->lock, flags);

	npages = PAGE_ALIGN(bus_addr + sz) - (bus_addr & PAGE_MASK);
	npages >>= PAGE_SHIFT;
	bus_addr &= PAGE_MASK;

	/* Step 1: Record the context, if any. */
	ctx = 0;
	if (iommu->iommu_ctxflush &&
	    strbuf->strbuf_ctxflush) {
		iopte_t *iopte;

		iopte = iommu->page_table +
			((bus_addr - iommu->page_table_map_base)>>PAGE_SHIFT);
		ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
	}

	/* Step 2: Kick data out of streaming buffers. */
	PCI_STC_FLUSHFLAG_INIT(strbuf);
	if (iommu->iommu_ctxflush &&
	    strbuf->strbuf_ctxflush) {
		unsigned long matchreg, flushreg;

		flushreg = strbuf->strbuf_ctxflush;
		matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
		do {
			pci_iommu_write(flushreg, ctx);
		} while(((long)pci_iommu_read(matchreg)) < 0L);
	} else {
		unsigned long i;

		for (i = 0; i < npages; i++, bus_addr += PAGE_SIZE)
			pci_iommu_write(strbuf->strbuf_pflush, bus_addr);
	}

	/* Step 3: Perform flush synchronization sequence. */
	pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
	(void) pci_iommu_read(iommu->write_complete_reg);
	while (!PCI_STC_FLUSHFLAG_SET(strbuf))
		membar("#LoadLoad");

	spin_unlock_irqrestore(&iommu->lock, flags);
}

/* Make physical memory consistant for a set of streaming
 * mode DMA translations after a transfer.
 */
void pci_dma_sync_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems)
{
	struct pcidev_cookie *pcp = pdev->sysdata;
	struct pci_iommu *iommu = &pcp->pbm->parent->iommu;
	struct pci_strbuf *strbuf = &pcp->pbm->stc;
	unsigned long flags, ctx;

	if (!strbuf->strbuf_enabled)
		return;

	spin_lock_irqsave(&iommu->lock, flags);

	/* Step 1: Record the context, if any. */
	ctx = 0;
	if (iommu->iommu_ctxflush &&
	    strbuf->strbuf_ctxflush) {
		iopte_t *iopte;

		iopte = iommu->page_table +
			((sglist[0].dvma_address - iommu->page_table_map_base) >> PAGE_SHIFT);
		ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
	}

	/* Step 2: Kick data out of streaming buffers. */
	PCI_STC_FLUSHFLAG_INIT(strbuf);
	if (iommu->iommu_ctxflush &&
	    strbuf->strbuf_ctxflush) {
		unsigned long matchreg, flushreg;

		flushreg = strbuf->strbuf_ctxflush;
		matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
		do {
			pci_iommu_write(flushreg, ctx);
		} while (((long)pci_iommu_read(matchreg)) < 0L);
	} else {
		unsigned long i, npages;
		u32 bus_addr;

		i = 0;
		bus_addr = sglist[0].dvma_address & PAGE_MASK;

		if (nelems > 1) {
			for(; i < nelems; i++)
				if (!sglist[i].dvma_length)
					break;
			i--;
		}
		npages = (PAGE_ALIGN(sglist[i].dvma_address + sglist[i].dvma_length) - bus_addr) >> PAGE_SHIFT;
		for (i = 0; i < npages; i++, bus_addr += PAGE_SIZE)
			pci_iommu_write(strbuf->strbuf_pflush, bus_addr);
	}

	/* Step 3: Perform flush synchronization sequence. */
	pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
	(void) pci_iommu_read(iommu->write_complete_reg);
	while (!PCI_STC_FLUSHFLAG_SET(strbuf))
		membar("#LoadLoad");

	spin_unlock_irqrestore(&iommu->lock, flags);
}