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pci-dma.c

/*
** 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/DMA-mapping.txt 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/mm.h>
#include <linux/pci.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/scatterlist.h>

#include <asm/cacheflush.h>
#include <asm/dma.h>    /* for DMA_CHUNK_SIZE */
#include <asm/io.h>
#include <asm/page.h>   /* get_order */
#include <asm/pgalloc.h>
#include <asm/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 = 0;
static unsigned long pcxl_used_pages __read_mostly = 0;

extern unsigned long pcxl_dma_start; /* Start of pcxl dma mapping area */
static spinlock_t   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 int pa11_dma_supported( struct device *dev, u64 mask)
{
      return 1;
}

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 {
            if (!pte_none(*pte))
                  printk(KERN_ERR "map_pte_uncached: page already exists\n");
            set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
            purge_tlb_start();
            pdtlb_kernel(orig_vaddr);
            purge_tlb_end();
            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 {
            pmd_t *pmd;
            
            pmd = pmd_alloc(NULL, dir, 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_map(pmd, vaddr);
      vaddr &= ~PMD_MASK;
      end = vaddr + size;
      if (end > PMD_SIZE)
            end = PMD_SIZE;
      do {
            pte_t page = *pte;
            pte_clear(&init_mm, vaddr, pte);
            purge_tlb_start();
            pdtlb_kernel(orig_vaddr);
            purge_tlb_end();
            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(dir, 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); \
}

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 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 proc_pcxl_dma_open(struct inode *inode, struct file *file)
{
      return single_open(file, proc_pcxl_dma_show, NULL);
}

static const struct file_operations proc_pcxl_dma_ops = {
      .owner            = THIS_MODULE,
      .open       = proc_pcxl_dma_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = single_release,
};

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

      spin_lock_init(&pcxl_res_lock);
      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("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 = create_proc_entry("pcxl_dma", 0, proc_gsc_root);
            if (ent)
                  ent->proc_fops = &proc_pcxl_dma_ops;
            else
                  printk(KERN_WARNING
                        "pci-dma.c: Unable to create pcxl_dma /proc entry.\n");
      }
      return 0;
}

__initcall(pcxl_dma_init);

static void * pa11_dma_alloc_consistent (struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag)
{
      unsigned long vaddr;
      unsigned long paddr;
      int order;

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

#if 0
/* This probably isn't needed to support EISA cards.
** ISA cards will certainly only support 24-bit DMA addressing.
** Not clear if we can, want, or need to support ISA.
*/
      if (!dev || *dev->coherent_dma_mask < 0xffffffff)
            gfp |= GFP_DMA;
#endif
      return (void *)vaddr;
}

static void pa11_dma_free_consistent (struct device *dev, size_t size, void *vaddr, dma_addr_t dma_handle)
{
      int order;

      order = get_order(size);
      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);
}

static dma_addr_t pa11_dma_map_single(struct device *dev, void *addr, size_t size, enum dma_data_direction direction)
{
      if (direction == DMA_NONE) {
            printk(KERN_ERR "pa11_dma_map_single(PCI_DMA_NONE) called by %p\n", __builtin_return_address(0));
            BUG();
      }

      flush_kernel_dcache_range((unsigned long) addr, size);
      return virt_to_phys(addr);
}

static void pa11_dma_unmap_single(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
{
      if (direction == DMA_NONE) {
            printk(KERN_ERR "pa11_dma_unmap_single(PCI_DMA_NONE) called by %p\n", __builtin_return_address(0));
            BUG();
      }

      if (direction == DMA_TO_DEVICE)
          return;

      /*
       * For PCI_DMA_FROMDEVICE this flush is not necessary for the
       * simple map/unmap case. However, it IS necessary if if
       * pci_dma_sync_single_* has been called and the buffer reused.
       */

      flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle), size);
      return;
}

static int pa11_dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
      int i;

      if (direction == DMA_NONE)
          BUG();

      for (i = 0; i < nents; i++, sglist++ ) {
            unsigned long vaddr = sg_virt_addr(sglist);
            sg_dma_address(sglist) = (dma_addr_t) virt_to_phys(vaddr);
            sg_dma_len(sglist) = sglist->length;
            flush_kernel_dcache_range(vaddr, sglist->length);
      }
      return nents;
}

static void pa11_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
      int i;

      if (direction == DMA_NONE)
          BUG();

      if (direction == DMA_TO_DEVICE)
          return;

      /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */

      for (i = 0; i < nents; i++, sglist++ )
            flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
      return;
}

static void pa11_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, enum dma_data_direction direction)
{
      if (direction == DMA_NONE)
          BUG();

      flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle) + offset, size);
}

static void pa11_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, enum dma_data_direction direction)
{
      if (direction == DMA_NONE)
          BUG();

      flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle) + offset, size);
}

static void pa11_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
      int i;

      /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */

      for (i = 0; i < nents; i++, sglist++ )
            flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
}

static void pa11_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
      int i;

      /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */

      for (i = 0; i < nents; i++, sglist++ )
            flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
}

struct hppa_dma_ops pcxl_dma_ops = {
      .dma_supported =  pa11_dma_supported,
      .alloc_consistent =     pa11_dma_alloc_consistent,
      .alloc_noncoherent =    pa11_dma_alloc_consistent,
      .free_consistent =      pa11_dma_free_consistent,
      .map_single =           pa11_dma_map_single,
      .unmap_single =         pa11_dma_unmap_single,
      .map_sg =         pa11_dma_map_sg,
      .unmap_sg =       pa11_dma_unmap_sg,
      .dma_sync_single_for_cpu = pa11_dma_sync_single_for_cpu,
      .dma_sync_single_for_device = pa11_dma_sync_single_for_device,
      .dma_sync_sg_for_cpu = pa11_dma_sync_sg_for_cpu,
      .dma_sync_sg_for_device = pa11_dma_sync_sg_for_device,
};

static void *fail_alloc_consistent(struct device *dev, size_t size,
                           dma_addr_t *dma_handle, gfp_t flag)
{
      return NULL;
}

static void *pa11_dma_alloc_noncoherent(struct device *dev, size_t size,
                                dma_addr_t *dma_handle, gfp_t flag)
{
      void *addr;

      addr = (void *)__get_free_pages(flag, get_order(size));
      if (addr)
            *dma_handle = (dma_addr_t)virt_to_phys(addr);

      return addr;
}

static void pa11_dma_free_noncoherent(struct device *dev, size_t size,
                              void *vaddr, dma_addr_t iova)
{
      free_pages((unsigned long)vaddr, get_order(size));
      return;
}

struct hppa_dma_ops pcx_dma_ops = {
      .dma_supported =  pa11_dma_supported,
      .alloc_consistent =     fail_alloc_consistent,
      .alloc_noncoherent =    pa11_dma_alloc_noncoherent,
      .free_consistent =      pa11_dma_free_noncoherent,
      .map_single =           pa11_dma_map_single,
      .unmap_single =         pa11_dma_unmap_single,
      .map_sg =         pa11_dma_map_sg,
      .unmap_sg =       pa11_dma_unmap_sg,
      .dma_sync_single_for_cpu =    pa11_dma_sync_single_for_cpu,
      .dma_sync_single_for_device = pa11_dma_sync_single_for_device,
      .dma_sync_sg_for_cpu =        pa11_dma_sync_sg_for_cpu,
      .dma_sync_sg_for_device =     pa11_dma_sync_sg_for_device,
};

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