arch/parisc/kernel/pci-dma.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
 ** PARISC 1.1 Dynamic DMA mapping support.
 ** This implementation is for PA-RISC platforms that do not support
 ** I/O TLBs (aka DMA address translation hardware).
 ** See Documentation/core-api/dma-api-howto.rst for interface definitions.
 **
 **      (c) Copyright 1999,2000 Hewlett-Packard Company
 **      (c) Copyright 2000 Grant Grundler
 **	(c) Copyright 2000 Philipp Rumpf <prumpf@tux.org>
 **      (c) Copyright 2000 John Marvin
 **
 ** "leveraged" from 2.3.47: arch/ia64/kernel/pci-dma.c.
 ** (I assume it's from David Mosberger-Tang but there was no Copyright)
 **
 ** AFAIK, all PA7100LC and PA7300LC platforms can use this code.
 **
 ** - ggg
 */

 #include <linux/init.h>
 #include <linux/gfp.h>
 #include <linux/mm.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/dma-direct.h>
 #include <linux/dma-map-ops.h>

 #include <asm/cacheflush.h>
 #include <asm/dma.h>    /* for DMA_CHUNK_SIZE */
 #include <asm/io.h>
 #include <asm/page.h>	/* get_order */
 #include <linux/uaccess.h>
 #include <asm/tlbflush.h>	/* for purge_tlb_*() macros */

 static struct proc_dir_entry * proc_gsc_root __read_mostly = NULL;
 static unsigned long pcxl_used_bytes __read_mostly;
 static unsigned long pcxl_used_pages __read_mostly;

 unsigned long pcxl_dma_start __ro_after_init; /* pcxl dma mapping area start */
 static DEFINE_SPINLOCK(pcxl_res_lock);
 static char    *pcxl_res_map;
 static int     pcxl_res_hint;
 static int     pcxl_res_size;

 #ifdef DEBUG_PCXL_RESOURCE
 #define DBG_RES(x...)	printk(x)
 #else
 #define DBG_RES(x...)
 #endif


 /*
 ** Dump a hex representation of the resource map.
 */

 #ifdef DUMP_RESMAP
 static
 void dump_resmap(void)
 {
 	u_long *res_ptr = (unsigned long *)pcxl_res_map;
 	u_long i = 0;

 	printk("res_map: ");
 	for(; i < (pcxl_res_size / sizeof(unsigned long)); ++i, ++res_ptr)
 		printk("%08lx ", *res_ptr);

 	printk("\n");
 }
 #else
 static inline void dump_resmap(void) {;}
 #endif

 static inline int map_pte_uncached(pte_t * pte,
 		unsigned long vaddr,
 		unsigned long size, unsigned long *paddr_ptr)
 {
 	unsigned long end;
 	unsigned long orig_vaddr = vaddr;

 	vaddr &= ~PMD_MASK;
 	end = vaddr + size;
 	if (end > PMD_SIZE)
 		end = PMD_SIZE;
 	do {
 		unsigned long flags;

 		if (!pte_none(*pte))
 			printk(KERN_ERR "map_pte_uncached: page already exists\n");
 		purge_tlb_start(flags);
 		set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
 		pdtlb(SR_KERNEL, orig_vaddr);
 		purge_tlb_end(flags);
 		vaddr += PAGE_SIZE;
 		orig_vaddr += PAGE_SIZE;
 		(*paddr_ptr) += PAGE_SIZE;
 		pte++;
 	} while (vaddr < end);
 	return 0;
 }

 static inline int map_pmd_uncached(pmd_t * pmd, unsigned long vaddr,
 		unsigned long size, unsigned long *paddr_ptr)
 {
 	unsigned long end;
 	unsigned long orig_vaddr = vaddr;

 	vaddr &= ~PGDIR_MASK;
 	end = vaddr + size;
 	if (end > PGDIR_SIZE)
 		end = PGDIR_SIZE;
 	do {
 		pte_t * pte = pte_alloc_kernel(pmd, vaddr);
 		if (!pte)
 			return -ENOMEM;
 		if (map_pte_uncached(pte, orig_vaddr, end - vaddr, paddr_ptr))
 			return -ENOMEM;
 		vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
 		orig_vaddr += PMD_SIZE;
 		pmd++;
 	} while (vaddr < end);
 	return 0;
 }

 static inline int map_uncached_pages(unsigned long vaddr, unsigned long size,
 		unsigned long paddr)
 {
 	pgd_t * dir;
 	unsigned long end = vaddr + size;

 	dir = pgd_offset_k(vaddr);
 	do {
 		p4d_t *p4d;
 		pud_t *pud;
 		pmd_t *pmd;

 		p4d = p4d_offset(dir, vaddr);
 		pud = pud_offset(p4d, vaddr);
 		pmd = pmd_alloc(NULL, pud, vaddr);

 		if (!pmd)
 			return -ENOMEM;
 		if (map_pmd_uncached(pmd, vaddr, end - vaddr, &paddr))
 			return -ENOMEM;
 		vaddr = vaddr + PGDIR_SIZE;
 		dir++;
 	} while (vaddr && (vaddr < end));
 	return 0;
 }

 static inline void unmap_uncached_pte(pmd_t * pmd, unsigned long vaddr,
 		unsigned long size)
 {
 	pte_t * pte;
 	unsigned long end;
 	unsigned long orig_vaddr = vaddr;

 	if (pmd_none(*pmd))
 		return;
 	if (pmd_bad(*pmd)) {
 		pmd_ERROR(*pmd);
 		pmd_clear(pmd);
 		return;
 	}
 	pte = pte_offset_kernel(pmd, vaddr);
 	vaddr &= ~PMD_MASK;
 	end = vaddr + size;
 	if (end > PMD_SIZE)
 		end = PMD_SIZE;
 	do {
 		unsigned long flags;
 		pte_t page = *pte;

 		pte_clear(&init_mm, vaddr, pte);
 		purge_tlb_start(flags);
 		pdtlb(SR_KERNEL, orig_vaddr);
 		purge_tlb_end(flags);
 		vaddr += PAGE_SIZE;
 		orig_vaddr += PAGE_SIZE;
 		pte++;
 		if (pte_none(page) || pte_present(page))
 			continue;
 		printk(KERN_CRIT "Whee.. Swapped out page in kernel page table\n");
 	} while (vaddr < end);
 }

 static inline void unmap_uncached_pmd(pgd_t * dir, unsigned long vaddr,
 		unsigned long size)
 {
 	pmd_t * pmd;
 	unsigned long end;
 	unsigned long orig_vaddr = vaddr;

 	if (pgd_none(*dir))
 		return;
 	if (pgd_bad(*dir)) {
 		pgd_ERROR(*dir);
 		pgd_clear(dir);
 		return;
 	}
 	pmd = pmd_offset(pud_offset(p4d_offset(dir, vaddr), vaddr), vaddr);
 	vaddr &= ~PGDIR_MASK;
 	end = vaddr + size;
 	if (end > PGDIR_SIZE)
 		end = PGDIR_SIZE;
 	do {
 		unmap_uncached_pte(pmd, orig_vaddr, end - vaddr);
 		vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
 		orig_vaddr += PMD_SIZE;
 		pmd++;
 	} while (vaddr < end);
 }

 static void unmap_uncached_pages(unsigned long vaddr, unsigned long size)
 {
 	pgd_t * dir;
 	unsigned long end = vaddr + size;

 	dir = pgd_offset_k(vaddr);
 	do {
 		unmap_uncached_pmd(dir, vaddr, end - vaddr);
 		vaddr = vaddr + PGDIR_SIZE;
 		dir++;
 	} while (vaddr && (vaddr < end));
 }

 #define PCXL_SEARCH_LOOP(idx, mask, size)  \
        for(; res_ptr < res_end; ++res_ptr) \
        { \
                if(0 == ((*res_ptr) & mask)) { \
                        *res_ptr |= mask; \
 		       idx = (int)((u_long)res_ptr - (u_long)pcxl_res_map); \
 		       pcxl_res_hint = idx + (size >> 3); \
                        goto resource_found; \
                } \
        }

 #define PCXL_FIND_FREE_MAPPING(idx, mask, size)  { \
        u##size *res_ptr = (u##size *)&(pcxl_res_map[pcxl_res_hint & ~((size >> 3) - 1)]); \
        u##size *res_end = (u##size *)&pcxl_res_map[pcxl_res_size]; \
        PCXL_SEARCH_LOOP(idx, mask, size); \
        res_ptr = (u##size *)&pcxl_res_map[0]; \
        PCXL_SEARCH_LOOP(idx, mask, size); \
 }

 static unsigned long
 pcxl_alloc_range(size_t size)
 {
 	int res_idx;
 	u_long mask, flags;
 	unsigned int pages_needed = size >> PAGE_SHIFT;

 	mask = (u_long) -1L;
  	mask >>= BITS_PER_LONG - pages_needed;

 	DBG_RES("pcxl_alloc_range() size: %d pages_needed %d pages_mask 0x%08lx\n",
 		size, pages_needed, mask);

 	spin_lock_irqsave(&pcxl_res_lock, flags);

 	if(pages_needed <= 8) {
 		PCXL_FIND_FREE_MAPPING(res_idx, mask, 8);
 	} else if(pages_needed <= 16) {
 		PCXL_FIND_FREE_MAPPING(res_idx, mask, 16);
 	} else if(pages_needed <= 32) {
 		PCXL_FIND_FREE_MAPPING(res_idx, mask, 32);
 	} else {
 		panic("%s: pcxl_alloc_range() Too many pages to map.\n",
 		      __FILE__);
 	}

 	dump_resmap();
 	panic("%s: pcxl_alloc_range() out of dma mapping resources\n",
 	      __FILE__);

 resource_found:

 	DBG_RES("pcxl_alloc_range() res_idx %d mask 0x%08lx res_hint: %d\n",
 		res_idx, mask, pcxl_res_hint);

 	pcxl_used_pages += pages_needed;
 	pcxl_used_bytes += ((pages_needed >> 3) ? (pages_needed >> 3) : 1);

 	spin_unlock_irqrestore(&pcxl_res_lock, flags);

 	dump_resmap();

 	/*
 	** return the corresponding vaddr in the pcxl dma map
 	*/
 	return (pcxl_dma_start + (res_idx << (PAGE_SHIFT + 3)));
 }

 #define PCXL_FREE_MAPPINGS(idx, m, size) \
 		u##size *res_ptr = (u##size *)&(pcxl_res_map[(idx) + (((size >> 3) - 1) & (~((size >> 3) - 1)))]); \
 		/* BUG_ON((*res_ptr & m) != m); */ \
 		*res_ptr &= ~m;

 /*
 ** clear bits in the pcxl resource map
 */
 static void
 pcxl_free_range(unsigned long vaddr, size_t size)
 {
 	u_long mask, flags;
 	unsigned int res_idx = (vaddr - pcxl_dma_start) >> (PAGE_SHIFT + 3);
 	unsigned int pages_mapped = size >> PAGE_SHIFT;

 	mask = (u_long) -1L;
  	mask >>= BITS_PER_LONG - pages_mapped;

 	DBG_RES("pcxl_free_range() res_idx: %d size: %d pages_mapped %d mask 0x%08lx\n",
 		res_idx, size, pages_mapped, mask);

 	spin_lock_irqsave(&pcxl_res_lock, flags);

 	if(pages_mapped <= 8) {
 		PCXL_FREE_MAPPINGS(res_idx, mask, 8);
 	} else if(pages_mapped <= 16) {
 		PCXL_FREE_MAPPINGS(res_idx, mask, 16);
 	} else if(pages_mapped <= 32) {
 		PCXL_FREE_MAPPINGS(res_idx, mask, 32);
 	} else {
 		panic("%s: pcxl_free_range() Too many pages to unmap.\n",
 		      __FILE__);
 	}

 	pcxl_used_pages -= (pages_mapped ? pages_mapped : 1);
 	pcxl_used_bytes -= ((pages_mapped >> 3) ? (pages_mapped >> 3) : 1);

 	spin_unlock_irqrestore(&pcxl_res_lock, flags);

 	dump_resmap();
 }

 static int __maybe_unused proc_pcxl_dma_show(struct seq_file *m, void *v)
 {
 #if 0
 	u_long i = 0;
 	unsigned long *res_ptr = (u_long *)pcxl_res_map;
 #endif
 	unsigned long total_pages = pcxl_res_size << 3;   /* 8 bits per byte */

 	seq_printf(m, "\nDMA Mapping Area size    : %d bytes (%ld pages)\n",
 		PCXL_DMA_MAP_SIZE, total_pages);

 	seq_printf(m, "Resource bitmap : %d bytes\n", pcxl_res_size);

 	seq_puts(m,  "     	  total:    free:    used:   % used:\n");
 	seq_printf(m, "blocks  %8d %8ld %8ld %8ld%%\n", pcxl_res_size,
 		pcxl_res_size - pcxl_used_bytes, pcxl_used_bytes,
 		(pcxl_used_bytes * 100) / pcxl_res_size);

 	seq_printf(m, "pages   %8ld %8ld %8ld %8ld%%\n", total_pages,
 		total_pages - pcxl_used_pages, pcxl_used_pages,
 		(pcxl_used_pages * 100 / total_pages));

 #if 0
 	seq_puts(m, "\nResource bitmap:");

 	for(; i < (pcxl_res_size / sizeof(u_long)); ++i, ++res_ptr) {
 		if ((i & 7) == 0)
 		    seq_puts(m,"\n   ");
 		seq_printf(m, "%s %08lx", buf, *res_ptr);
 	}
 #endif
 	seq_putc(m, '\n');
 	return 0;
 }

 static int __init
 pcxl_dma_init(void)
 {
 	if (pcxl_dma_start == 0)
 		return 0;

 	pcxl_res_size = PCXL_DMA_MAP_SIZE >> (PAGE_SHIFT + 3);
 	pcxl_res_hint = 0;
 	pcxl_res_map = (char *)__get_free_pages(GFP_KERNEL,
 					    get_order(pcxl_res_size));
 	memset(pcxl_res_map, 0, pcxl_res_size);
 	proc_gsc_root = proc_mkdir("bus/gsc", NULL);
 	if (!proc_gsc_root)
     		printk(KERN_WARNING
 			"pcxl_dma_init: Unable to create gsc /proc dir entry\n");
 	else {
 		struct proc_dir_entry* ent;
 		ent = proc_create_single("pcxl_dma", 0, proc_gsc_root,
 				proc_pcxl_dma_show);
 		if (!ent)
 			printk(KERN_WARNING
 				"pci-dma.c: Unable to create pcxl_dma /proc entry.\n");
 	}
 	return 0;
 }

 __initcall(pcxl_dma_init);

 void *arch_dma_alloc(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 {
 	unsigned long vaddr;
 	unsigned long paddr;
 	int order;

 	if (boot_cpu_data.cpu_type != pcxl2 && boot_cpu_data.cpu_type != pcxl)
 		return NULL;

 	order = get_order(size);
 	size = 1 << (order + PAGE_SHIFT);
 	vaddr = pcxl_alloc_range(size);
 	paddr = __get_free_pages(gfp | __GFP_ZERO, order);
 	flush_kernel_dcache_range(paddr, size);
 	paddr = __pa(paddr);
 	map_uncached_pages(vaddr, size, paddr);
 	*dma_handle = (dma_addr_t) paddr;

 	return (void *)vaddr;
 }

 void arch_dma_free(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_handle, unsigned long attrs)
 {
 	int order = get_order(size);

 	WARN_ON_ONCE(boot_cpu_data.cpu_type != pcxl2 &&
 		     boot_cpu_data.cpu_type != pcxl);

 	size = 1 << (order + PAGE_SHIFT);
 	unmap_uncached_pages((unsigned long)vaddr, size);
 	pcxl_free_range((unsigned long)vaddr, size);

 	free_pages((unsigned long)__va(dma_handle), order);
 }

 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
 		enum dma_data_direction dir)
 {
 	/*
 	 * fdc: The data cache line is written back to memory, if and only if
 	 * it is dirty, and then invalidated from the data cache.
 	 */
 	flush_kernel_dcache_range((unsigned long)phys_to_virt(paddr), size);
 }

 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 		enum dma_data_direction dir)
 {
 	unsigned long addr = (unsigned long) phys_to_virt(paddr);

 	switch (dir) {
 	case DMA_TO_DEVICE:
 	case DMA_BIDIRECTIONAL:
 		flush_kernel_dcache_range(addr, size);
 		return;
 	case DMA_FROM_DEVICE:
 		purge_kernel_dcache_range_asm(addr, addr + size);
 		return;
 	default:
 		BUG();
 	}
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	** PARISC 1.1 Dynamic DMA mapping support.
	** This implementation is for PA-RISC platforms that do not support
	** I/O TLBs (aka DMA address translation hardware).
	** See Documentation/core-api/dma-api-howto.rst for interface definitions.
	**
	** (c) Copyright 1999,2000 Hewlett-Packard Company
	** (c) Copyright 2000 Grant Grundler
	** (c) Copyright 2000 Philipp Rumpf <prumpf@tux.org>
	** (c) Copyright 2000 John Marvin
	**
	** "leveraged" from 2.3.47: arch/ia64/kernel/pci-dma.c.
	** (I assume it's from David Mosberger-Tang but there was no Copyright)
	**
	** AFAIK, all PA7100LC and PA7300LC platforms can use this code.
	**
	** - ggg
	*/

	#include <linux/init.h>
	#include <linux/gfp.h>
	#include <linux/mm.h>
	#include <linux/proc_fs.h>
	#include <linux/seq_file.h>
	#include <linux/string.h>
	#include <linux/types.h>
	#include <linux/dma-direct.h>
	#include <linux/dma-map-ops.h>

	#include <asm/cacheflush.h>
	#include <asm/dma.h> /* for DMA_CHUNK_SIZE */
	#include <asm/io.h>
	#include <asm/page.h> /* get_order */
	#include <linux/uaccess.h>
	#include <asm/tlbflush.h> /* for purge_tlb_() macros /

	static struct proc_dir_entry * proc_gsc_root __read_mostly = NULL;
	static unsigned long pcxl_used_bytes __read_mostly;
	static unsigned long pcxl_used_pages __read_mostly;

	unsigned long pcxl_dma_start __ro_after_init; /* pcxl dma mapping area start */
	static DEFINE_SPINLOCK(pcxl_res_lock);
	static char *pcxl_res_map;
	static int pcxl_res_hint;
	static int pcxl_res_size;

	#ifdef DEBUG_PCXL_RESOURCE
	#define DBG_RES(x...) printk(x)
	#else
	#define DBG_RES(x...)
	#endif


	/*
	** Dump a hex representation of the resource map.
	*/

	#ifdef DUMP_RESMAP
	static
	void dump_resmap(void)
	{
	u_long res_ptr = (unsigned long )pcxl_res_map;
	u_long i = 0;

	printk("res_map: ");
	for(; i < (pcxl_res_size / sizeof(unsigned long)); ++i, ++res_ptr)
	printk("%08lx ", *res_ptr);

	printk("\n");
	}
	#else
	static inline void dump_resmap(void) {;}
	#endif

	static inline int map_pte_uncached(pte_t * pte,
	unsigned long vaddr,
	unsigned long size, unsigned long *paddr_ptr)
	{
	unsigned long end;
	unsigned long orig_vaddr = vaddr;

	vaddr &= ~PMD_MASK;
	end = vaddr + size;
	if (end > PMD_SIZE)
	end = PMD_SIZE;
	do {
	unsigned long flags;

	if (!pte_none(*pte))
	printk(KERN_ERR "map_pte_uncached: page already exists\n");
	purge_tlb_start(flags);
	set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
	pdtlb(SR_KERNEL, orig_vaddr);
	purge_tlb_end(flags);
	vaddr += PAGE_SIZE;
	orig_vaddr += PAGE_SIZE;
	(*paddr_ptr) += PAGE_SIZE;
	pte++;
	} while (vaddr < end);
	return 0;
	}

	static inline int map_pmd_uncached(pmd_t * pmd, unsigned long vaddr,
	unsigned long size, unsigned long *paddr_ptr)
	{
	unsigned long end;
	unsigned long orig_vaddr = vaddr;

	vaddr &= ~PGDIR_MASK;
	end = vaddr + size;
	if (end > PGDIR_SIZE)
	end = PGDIR_SIZE;
	do {
	pte_t * pte = pte_alloc_kernel(pmd, vaddr);
	if (!pte)
	return -ENOMEM;
	if (map_pte_uncached(pte, orig_vaddr, end - vaddr, paddr_ptr))
	return -ENOMEM;
	vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
	orig_vaddr += PMD_SIZE;
	pmd++;
	} while (vaddr < end);
	return 0;
	}

	static inline int map_uncached_pages(unsigned long vaddr, unsigned long size,
	unsigned long paddr)
	{
	pgd_t * dir;
	unsigned long end = vaddr + size;

	dir = pgd_offset_k(vaddr);
	do {
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;

	p4d = p4d_offset(dir, vaddr);
	pud = pud_offset(p4d, vaddr);
	pmd = pmd_alloc(NULL, pud, vaddr);

	if (!pmd)
	return -ENOMEM;
	if (map_pmd_uncached(pmd, vaddr, end - vaddr, &paddr))
	return -ENOMEM;
	vaddr = vaddr + PGDIR_SIZE;
	dir++;
	} while (vaddr && (vaddr < end));
	return 0;
	}

	static inline void unmap_uncached_pte(pmd_t * pmd, unsigned long vaddr,
	unsigned long size)
	{
	pte_t * pte;
	unsigned long end;
	unsigned long orig_vaddr = vaddr;

	if (pmd_none(*pmd))
	return;
	if (pmd_bad(*pmd)) {
	pmd_ERROR(*pmd);
	pmd_clear(pmd);
	return;
	}
	pte = pte_offset_kernel(pmd, vaddr);
	vaddr &= ~PMD_MASK;
	end = vaddr + size;
	if (end > PMD_SIZE)
	end = PMD_SIZE;
	do {
	unsigned long flags;
	pte_t page = *pte;

	pte_clear(&init_mm, vaddr, pte);
	purge_tlb_start(flags);
	pdtlb(SR_KERNEL, orig_vaddr);
	purge_tlb_end(flags);
	vaddr += PAGE_SIZE;
	orig_vaddr += PAGE_SIZE;
	pte++;
	if (pte_none(page) \|\| pte_present(page))
	continue;
	printk(KERN_CRIT "Whee.. Swapped out page in kernel page table\n");
	} while (vaddr < end);
	}

	static inline void unmap_uncached_pmd(pgd_t * dir, unsigned long vaddr,
	unsigned long size)
	{
	pmd_t * pmd;
	unsigned long end;
	unsigned long orig_vaddr = vaddr;

	if (pgd_none(*dir))
	return;
	if (pgd_bad(*dir)) {
	pgd_ERROR(*dir);
	pgd_clear(dir);
	return;
	}
	pmd = pmd_offset(pud_offset(p4d_offset(dir, vaddr), vaddr), vaddr);
	vaddr &= ~PGDIR_MASK;
	end = vaddr + size;
	if (end > PGDIR_SIZE)
	end = PGDIR_SIZE;
	do {
	unmap_uncached_pte(pmd, orig_vaddr, end - vaddr);
	vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
	orig_vaddr += PMD_SIZE;
	pmd++;
	} while (vaddr < end);
	}

	static void unmap_uncached_pages(unsigned long vaddr, unsigned long size)
	{
	pgd_t * dir;
	unsigned long end = vaddr + size;

	dir = pgd_offset_k(vaddr);
	do {
	unmap_uncached_pmd(dir, vaddr, end - vaddr);
	vaddr = vaddr + PGDIR_SIZE;
	dir++;
	} while (vaddr && (vaddr < end));
	}

	#define PCXL_SEARCH_LOOP(idx, mask, size) \
	for(; res_ptr < res_end; ++res_ptr) \
	{ \
	if(0 == ((*res_ptr) & mask)) { \
	*res_ptr \|= mask; \
	idx = (int)((u_long)res_ptr - (u_long)pcxl_res_map); \
	pcxl_res_hint = idx + (size >> 3); \
	goto resource_found; \
	} \
	}

	#define PCXL_FIND_FREE_MAPPING(idx, mask, size) { \
	u##size res_ptr = (u##size )&(pcxl_res_map[pcxl_res_hint & ~((size >> 3) - 1)]); \
	u##size res_end = (u##size )&pcxl_res_map[pcxl_res_size]; \
	PCXL_SEARCH_LOOP(idx, mask, size); \
	res_ptr = (u##size *)&pcxl_res_map[0]; \
	PCXL_SEARCH_LOOP(idx, mask, size); \
	}

	static unsigned long
	pcxl_alloc_range(size_t size)
	{
	int res_idx;
	u_long mask, flags;
	unsigned int pages_needed = size >> PAGE_SHIFT;

	mask = (u_long) -1L;
	mask >>= BITS_PER_LONG - pages_needed;

	DBG_RES("pcxl_alloc_range() size: %d pages_needed %d pages_mask 0x%08lx\n",
	size, pages_needed, mask);

	spin_lock_irqsave(&pcxl_res_lock, flags);

	if(pages_needed <= 8) {
	PCXL_FIND_FREE_MAPPING(res_idx, mask, 8);
	} else if(pages_needed <= 16) {
	PCXL_FIND_FREE_MAPPING(res_idx, mask, 16);
	} else if(pages_needed <= 32) {
	PCXL_FIND_FREE_MAPPING(res_idx, mask, 32);
	} else {
	panic("%s: pcxl_alloc_range() Too many pages to map.\n",
	__FILE__);
	}

	dump_resmap();
	panic("%s: pcxl_alloc_range() out of dma mapping resources\n",
	__FILE__);

	resource_found:

	DBG_RES("pcxl_alloc_range() res_idx %d mask 0x%08lx res_hint: %d\n",
	res_idx, mask, pcxl_res_hint);

	pcxl_used_pages += pages_needed;
	pcxl_used_bytes += ((pages_needed >> 3) ? (pages_needed >> 3) : 1);

	spin_unlock_irqrestore(&pcxl_res_lock, flags);

	dump_resmap();

	/*
	** return the corresponding vaddr in the pcxl dma map
	*/
	return (pcxl_dma_start + (res_idx << (PAGE_SHIFT + 3)));
	}

	#define PCXL_FREE_MAPPINGS(idx, m, size) \
	u##size res_ptr = (u##size )&(pcxl_res_map[(idx) + (((size >> 3) - 1) & (~((size >> 3) - 1)))]); \
	/* BUG_ON((res_ptr & m) != m); / \
	*res_ptr &= ~m;

	/*
	** clear bits in the pcxl resource map
	*/
	static void
	pcxl_free_range(unsigned long vaddr, size_t size)
	{
	u_long mask, flags;
	unsigned int res_idx = (vaddr - pcxl_dma_start) >> (PAGE_SHIFT + 3);
	unsigned int pages_mapped = size >> PAGE_SHIFT;

	mask = (u_long) -1L;
	mask >>= BITS_PER_LONG - pages_mapped;

	DBG_RES("pcxl_free_range() res_idx: %d size: %d pages_mapped %d mask 0x%08lx\n",
	res_idx, size, pages_mapped, mask);

	spin_lock_irqsave(&pcxl_res_lock, flags);

	if(pages_mapped <= 8) {
	PCXL_FREE_MAPPINGS(res_idx, mask, 8);
	} else if(pages_mapped <= 16) {
	PCXL_FREE_MAPPINGS(res_idx, mask, 16);
	} else if(pages_mapped <= 32) {
	PCXL_FREE_MAPPINGS(res_idx, mask, 32);
	} else {
	panic("%s: pcxl_free_range() Too many pages to unmap.\n",
	__FILE__);
	}

	pcxl_used_pages -= (pages_mapped ? pages_mapped : 1);
	pcxl_used_bytes -= ((pages_mapped >> 3) ? (pages_mapped >> 3) : 1);

	spin_unlock_irqrestore(&pcxl_res_lock, flags);

	dump_resmap();
	}

	static int __maybe_unused proc_pcxl_dma_show(struct seq_file m, void v)
	{
	#if 0
	u_long i = 0;
	unsigned long res_ptr = (u_long )pcxl_res_map;
	#endif
	unsigned long total_pages = pcxl_res_size << 3; /* 8 bits per byte */

	seq_printf(m, "\nDMA Mapping Area size : %d bytes (%ld pages)\n",
	PCXL_DMA_MAP_SIZE, total_pages);

	seq_printf(m, "Resource bitmap : %d bytes\n", pcxl_res_size);

	seq_puts(m, " total: free: used: % used:\n");
	seq_printf(m, "blocks %8d %8ld %8ld %8ld%%\n", pcxl_res_size,
	pcxl_res_size - pcxl_used_bytes, pcxl_used_bytes,
	(pcxl_used_bytes * 100) / pcxl_res_size);

	seq_printf(m, "pages %8ld %8ld %8ld %8ld%%\n", total_pages,
	total_pages - pcxl_used_pages, pcxl_used_pages,
	(pcxl_used_pages * 100 / total_pages));

	#if 0
	seq_puts(m, "\nResource bitmap:");

	for(; i < (pcxl_res_size / sizeof(u_long)); ++i, ++res_ptr) {
	if ((i & 7) == 0)
	seq_puts(m,"\n ");
	seq_printf(m, "%s %08lx", buf, *res_ptr);
	}
	#endif
	seq_putc(m, '\n');
	return 0;
	}

	static int __init
	pcxl_dma_init(void)
	{
	if (pcxl_dma_start == 0)
	return 0;

	pcxl_res_size = PCXL_DMA_MAP_SIZE >> (PAGE_SHIFT + 3);
	pcxl_res_hint = 0;
	pcxl_res_map = (char *)__get_free_pages(GFP_KERNEL,
	get_order(pcxl_res_size));
	memset(pcxl_res_map, 0, pcxl_res_size);
	proc_gsc_root = proc_mkdir("bus/gsc", NULL);
	if (!proc_gsc_root)
	printk(KERN_WARNING
	"pcxl_dma_init: Unable to create gsc /proc dir entry\n");
	else {
	struct proc_dir_entry* ent;
	ent = proc_create_single("pcxl_dma", 0, proc_gsc_root,
	proc_pcxl_dma_show);
	if (!ent)
	printk(KERN_WARNING
	"pci-dma.c: Unable to create pcxl_dma /proc entry.\n");
	}
	return 0;
	}

	__initcall(pcxl_dma_init);

	void arch_dma_alloc(struct device dev, size_t size,
	dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
	{
	unsigned long vaddr;
	unsigned long paddr;
	int order;

	if (boot_cpu_data.cpu_type != pcxl2 && boot_cpu_data.cpu_type != pcxl)
	return NULL;

	order = get_order(size);
	size = 1 << (order + PAGE_SHIFT);
	vaddr = pcxl_alloc_range(size);
	paddr = __get_free_pages(gfp \| __GFP_ZERO, order);
	flush_kernel_dcache_range(paddr, size);
	paddr = __pa(paddr);
	map_uncached_pages(vaddr, size, paddr);
	*dma_handle = (dma_addr_t) paddr;

	return (void *)vaddr;
	}

	void arch_dma_free(struct device dev, size_t size, void vaddr,
	dma_addr_t dma_handle, unsigned long attrs)
	{
	int order = get_order(size);

	WARN_ON_ONCE(boot_cpu_data.cpu_type != pcxl2 &&
	boot_cpu_data.cpu_type != pcxl);

	size = 1 << (order + PAGE_SHIFT);
	unmap_uncached_pages((unsigned long)vaddr, size);
	pcxl_free_range((unsigned long)vaddr, size);

	free_pages((unsigned long)__va(dma_handle), order);
	}

	void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
	enum dma_data_direction dir)
	{
	/*
	* fdc: The data cache line is written back to memory, if and only if
	* it is dirty, and then invalidated from the data cache.
	*/
	flush_kernel_dcache_range((unsigned long)phys_to_virt(paddr), size);
	}

	void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
	enum dma_data_direction dir)
	{
	unsigned long addr = (unsigned long) phys_to_virt(paddr);

	switch (dir) {
	case DMA_TO_DEVICE:
	case DMA_BIDIRECTIONAL:
	flush_kernel_dcache_range(addr, size);
	return;
	case DMA_FROM_DEVICE:
	purge_kernel_dcache_range_asm(addr, addr + size);
	return;
	default:
	BUG();
	}
	}