patch-2.2.8 linux/arch/m68k/sun3x/dvma.c

• Lines: 163
• Date: Tue May 11 09:57:14 1999
• Orig file: v2.2.7/linux/arch/m68k/sun3x/dvma.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.2.7/linux/arch/m68k/sun3x/dvma.c linux/arch/m68k/sun3x/dvma.c
@@ -0,0 +1,162 @@
+/*
+ * Virtual DMA allocation
+ *
+ * (C) 1999 Thomas Bogendoerfer (tsbogend@alpha.franken.de) 
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+#include <linux/mm.h>
+
+#include <asm/sun3x.h>
+#include <asm/dvma.h>
+#include <asm/io.h>
+#include <asm/page.h>
+
+/* IOMMU support */
+
+#define IOMMU_ENTRIES		   2048
+#define IOMMU_ADDR_MASK            0x03ffe000
+#define IOMMU_CACHE_INHIBIT        0x00000040
+#define IOMMU_FULL_BLOCK           0x00000020
+#define IOMMU_MODIFIED             0x00000010
+#define IOMMU_USED                 0x00000008
+#define IOMMU_WRITE_PROTECT        0x00000004
+#define IOMMU_DT_MASK              0x00000003
+#define IOMMU_DT_INVALID           0x00000000
+#define IOMMU_DT_VALID             0x00000001
+#define IOMMU_DT_BAD               0x00000002
+
+#define DVMA_PAGE_SHIFT	13
+#define DVMA_PAGE_SIZE	(1UL << DVMA_PAGE_SHIFT)
+#define DVMA_PAGE_MASK	(~(DVMA_PAGE_SIZE-1))
+
+
+static volatile unsigned long *iommu_pte = (unsigned long *)SUN3X_IOMMU;
+static unsigned long iommu_use[IOMMU_ENTRIES];
+static unsigned long iommu_bitmap[IOMMU_ENTRIES/32];
+
+
+#define dvma_entry_paddr(index) 	(iommu_pte[index] & IOMMU_ADDR_MASK)
+#define dvma_entry_vaddr(index,paddr) 	((index << DVMA_PAGE_SHIFT) |  \
+					 (paddr & (DVMA_PAGE_SIZE-1)))
+#define dvma_entry_set(index,addr)	(iommu_pte[index] =            \
+					    (addr & IOMMU_ADDR_MASK) | \
+				             IOMMU_DT_VALID)
+#define dvma_entry_clr(index)		(iommu_pte[index] = IOMMU_DT_INVALID)
+#define dvma_entry_use(index)		(iommu_use[index])
+#define dvma_entry_inc(index)		(iommu_use[index]++)
+#define dvma_entry_dec(index)		(iommu_use[index]--)
+#define dvma_entry_hash(addr)		((addr >> DVMA_PAGE_SHIFT) ^ \
+					 ((addr & 0x03c00000) >>     \
+						(DVMA_PAGE_SHIFT+4)))
+#define dvma_map			iommu_bitmap
+#define dvma_map_size			(IOMMU_ENTRIES/2)
+#define dvma_slow_offset		(IOMMU_ENTRIES/2)
+#define dvma_is_slow(addr)		((addr) & 		      \
+					 (dvma_slow_offset << DVMA_PAGE_SHIFT))
+
+static int fixed_dvma;
+
+void __init dvma_init(void)
+{
+    unsigned long tmp;
+
+    if ((unsigned long)high_memory < (IOMMU_ENTRIES << DVMA_PAGE_SHIFT)) {
+	printk ("Sun3x fixed DVMA mapping\n");
+	fixed_dvma = 1;
+	for (tmp = 0; tmp < (unsigned long)high_memory; tmp += DVMA_PAGE_SIZE)
+	dvma_entry_set (tmp >> DVMA_PAGE_SHIFT, virt_to_phys((void *)tmp));
+	fixed_dvma = 1;
+    } else {
+	printk ("Sun3x variable DVMA mapping\n");
+	for (tmp = 0; tmp < IOMMU_ENTRIES; tmp++)
+	    dvma_entry_clr (tmp);
+	fixed_dvma = 0;
+    }
+}
+
+unsigned long dvma_slow_alloc (unsigned long paddr, int npages)
+{
+    int scan, base;
+    
+    scan = 0;
+    for (;;) {
+	scan = find_next_zero_bit(dvma_map, dvma_map_size, scan);
+	if ((base = scan) + npages > dvma_map_size) {
+	    printk ("dvma_slow_alloc failed for %d pages\n",npages);
+	    return 0;
+	}
+	for  (;;) {
+	    if (scan >= base + npages) goto found;
+	    if (test_bit(scan, dvma_map)) break;
+	    scan++;
+	}
+    }
+
+found:
+    for (scan = base; scan < base+npages; scan++) {
+	dvma_entry_set(scan+dvma_slow_offset, paddr);
+	paddr += DVMA_PAGE_SIZE;
+	set_bit(scan, dvma_map);
+    }
+    return (dvma_entry_vaddr((base+dvma_slow_offset),paddr));
+}
+
+unsigned long dvma_alloc (unsigned long paddr, unsigned long size)
+{
+    int index;
+    int pages = ((paddr & ~DVMA_PAGE_MASK) + size + (DVMA_PAGE_SIZE-1)) >>
+		DVMA_PAGE_SHIFT;
+
+    if (fixed_dvma)
+	return ((unsigned long)phys_to_virt (paddr));
+
+    if (pages > 1) /* multi page, allocate from slow pool */
+	return dvma_slow_alloc (paddr, pages);
+    
+    index = dvma_entry_hash (paddr);
+
+    if (dvma_entry_use(index)) {
+	if (dvma_entry_paddr(index) == (paddr & DVMA_PAGE_MASK)) {
+	    dvma_entry_inc(index);
+	    return dvma_entry_vaddr(index,paddr);
+	}
+	/* collision, allocate from slow pool */
+	return dvma_slow_alloc (paddr, pages);
+    }
+    
+    dvma_entry_set(index,paddr); 
+    dvma_entry_inc(index);
+    return dvma_entry_vaddr(index,paddr);
+}
+
+void dvma_free (unsigned long dvma_addr, unsigned long size)
+{
+    int npages;
+    int index;
+    
+    if (fixed_dvma)
+	return;
+
+    if (!dvma_is_slow(dvma_addr)) {
+	index = (dvma_addr >> DVMA_PAGE_SHIFT);
+	if (dvma_entry_use(index) == 0) {
+	    printk ("dvma_free: %lx entry already free\n",dvma_addr);
+	    return;
+	}
+        dvma_entry_dec(index);
+	if (dvma_entry_use(index) == 0)
+	    dvma_entry_clr(index);
+	return;
+    }
+
+    /* free in slow pool */
+    npages = ((dvma_addr & ~DVMA_PAGE_MASK) + size + (DVMA_PAGE_SIZE-1)) >>
+	    DVMA_PAGE_SHIFT;
+    for (index = (dvma_addr >> DVMA_PAGE_SHIFT); npages--; index++) {
+	dvma_entry_clr(index);
+	clear_bit (index,dvma_map);
+    }
+}