path: root/arch/parisc/kernel/pci-dma.c

// 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/DMA-API-HOWTO.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/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-noncoherent.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 <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 = 0;
static unsigned long pcxl_used_pages __read_mostly = 0;

extern unsigned long pcxl_dma_start; /* Start of pcxl dma mapping area */
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_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_map(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_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); \
}

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"