patch-1.3.94 linux/arch/m68k/atari/stram.c

• Lines: 244
• Date: Wed Dec 27 22:44:28 1995
• Orig file: v1.3.93/linux/arch/m68k/atari/stram.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/atari/stram.c linux/arch/m68k/atari/stram.c
@@ -0,0 +1,243 @@
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <asm/bootinfo.h>
+#include <asm/atarihw.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+#if 0
+
+struct stram_desc
+  {
+    unsigned first:1;
+    unsigned last:1;
+    unsigned alloced:1;
+    unsigned length:24;
+  };
+
+#define DP(ptr) ((struct stram_desc *) (ptr))
+
+static unsigned long stramsize;
+static unsigned long stramaddr;
+
+void
+atari_stram_init (void)
+{
+  struct stram_desc *dp;
+  stramaddr = boot_info.bi_atari.stram_start;
+  stramsize = boot_info.bi_atari.stram_size;
+
+  /* initialize start boundary */
+  dp = DP (stramaddr);
+  dp->first = 1;
+  dp->alloced = 0;
+  dp->length = stramsize - 2 * sizeof (*dp);
+
+  /* initialize end boundary */
+  dp = DP (stramaddr + stramsize) - 1;
+  dp->last = 1;
+  dp->alloced = 0;
+  dp->length = stramsize - 2 * sizeof (*dp);
+
+#ifdef DEBUG
+  printk ("stram end boundary is %p, length is %d\n", dp,
+	  dp->length);
+#endif
+}
+
+void *
+atari_stram_alloc (long size)
+{
+  /* last chunk */
+  struct stram_desc *dp;
+  void *ptr;
+
+  /* round off */
+  size = (size + 3) & ~3;
+
+#ifdef DEBUG
+  printk ("stram_alloc: allocate %ld bytes\n", size);
+#endif
+
+  /*
+   * get pointer to descriptor for last chunk by 
+   * going backwards from end chunk
+   */
+  dp = DP (stramaddr + stramsize) - 1;
+  dp = DP ((unsigned long) dp - dp->length) - 1;
+
+  while ((dp->alloced || dp->length < size) && !dp->first)
+    dp = DP ((unsigned long) dp - dp[-1].length) - 2;
+
+  if (dp->alloced || dp->length < size)
+    {
+      printk ("no stram available for %ld allocation\n", size);
+      return NULL;
+    }
+
+  if (dp->length < size + 2 * sizeof (*dp))
+    {
+      /* length too small to split; allocate the whole thing */
+      dp->alloced = 1;
+      ptr = (void *) (dp + 1);
+      dp = DP ((unsigned long) ptr + dp->length);
+      dp->alloced = 1;
+#ifdef DEBUG
+      printk ("stram_alloc: no split\n");
+#endif
+    }
+  else
+    {
+      /* split the extent; use the end part */
+      long newsize = dp->length - (2 * sizeof (*dp) + size);
+
+#ifdef DEBUG
+      printk ("stram_alloc: splitting %d to %ld\n", dp->length,
+	      newsize);
+#endif
+      dp->length = newsize;
+      dp = DP ((unsigned long) (dp + 1) + newsize);
+      dp->first = dp->last = 0;
+      dp->alloced = 0;
+      dp->length = newsize;
+      dp++;
+      dp->first = dp->last = 0;
+      dp->alloced = 1;
+      dp->length = size;
+      ptr = (void *) (dp + 1);
+      dp = DP ((unsigned long) ptr + size);
+      dp->alloced = 1;
+      dp->length = size;
+    }
+
+#ifdef DEBUG
+  printk ("stram_alloc: returning %p\n", ptr);
+#endif
+  return ptr;
+}
+
+void 
+atari_stram_free (void *ptr)
+{
+  struct stram_desc *sdp = DP (ptr) - 1, *dp2;
+  struct stram_desc *edp = DP ((unsigned long) ptr + sdp->length);
+
+  /* deallocate the chunk */
+  sdp->alloced = edp->alloced = 0;
+
+  /* check if we should merge with the previous chunk */
+  if (!sdp->first && !sdp[-1].alloced)
+    {
+      dp2 = DP ((unsigned long) sdp - sdp[-1].length) - 2;
+      dp2->length += sdp->length + 2 * sizeof (*sdp);
+      edp->length = dp2->length;
+      sdp = dp2;
+    }
+
+  /* check if we should merge with the following chunk */
+  if (!edp->last && !edp[1].alloced)
+    {
+      dp2 = DP ((unsigned long) edp + edp[1].length) + 2;
+      dp2->length += edp->length + 2 * sizeof (*sdp);
+      sdp->length = dp2->length;
+      edp = dp2;
+    }
+}
+
+#else
+
+#include <linux/mm.h>
+
+/* ++roman:
+ * 
+ * New version of ST-Ram buffer allocation. Instead of using the
+ * 1 MB - 4 KB that remain when the the ST-Ram chunk starts at $1000
+ * (1 MB granularity!), such buffers are reserved like this:
+ *
+ *  - If the kernel resides in ST-Ram anyway, we can take the buffer
+ *    from behind the current kernel data space the normal way
+ *    (incrementing start_mem).
+ *    
+ *  - If the kernel is in TT-Ram, stram_init() initializes start and
+ *    end of the available region. Buffers are allocated from there
+ *    and mem_init() later marks the such used pages as reserved.
+ *    Since each TT-Ram chunk is at least 4 MB in size, I hope there
+ *    won't be an overrun of the ST-Ram region by normal kernel data
+ *    space.
+ *    
+ * For that, ST-Ram may only be allocated while kernel initialization
+ * is going on, or exactly: before mem_init() is called. There is also
+ * no provision now for freeing ST-Ram buffers. It seems that isn't
+ * really needed.
+ *
+ * ToDo:
+ * Check the high level scsi code what is done when the
+ * UNCHECKED_ISA_DMA flag is set. It guess, it is just a test for adr
+ * < 16 Mega. There should be call to atari_stram_alloc() instead.
+ *
+ * Also ToDo:
+ * Go through head.S and delete parts no longer needed (transparent
+ * mapping of ST-Ram etc.)
+ * 
+ */
+   
+
+unsigned long rsvd_stram_beg, rsvd_stram_end;
+    /* Start and end of the reserved ST-Ram region */
+static unsigned long stram_end;
+    /* Overall end of ST-Ram */
+
+
+void atari_stram_init( void )
+
+{	int		i;
+
+	for( i = 0; i < boot_info.num_memory; ++i ) {
+		if (boot_info.memory[i].addr == 0) {
+			rsvd_stram_beg = PTOV( 0x800 ); /* skip super-only first 2 KB! */
+			rsvd_stram_end = rsvd_stram_beg;
+			stram_end = rsvd_stram_beg - 0x800 + boot_info.memory[i].size;
+			return;
+		}
+	}
+	/* Should never come here! (There is always ST-Ram!) */
+}
+
+
+void *atari_stram_alloc( long size, unsigned long *start_mem )
+
+{
+	static int				kernel_in_stram = -1;
+	
+	void	*adr = 0;
+	
+	if (kernel_in_stram < 0)
+		kernel_in_stram = (PTOV( 0 ) == 0);
+
+	if (kernel_in_stram) {
+		/* Get memory from kernel data space */
+		adr = (void *) *start_mem;
+		*start_mem += size;
+	}
+	else {
+		/* Get memory from rsvd_stram_beg */
+		if (rsvd_stram_end + size < stram_end) {
+			adr = (void *) rsvd_stram_end;
+			rsvd_stram_end += size;
+		}
+	}
+	
+	return( adr );
+}
+
+void atari_stram_free( void *ptr )
+
+{
+	/* Sorry, this is a dummy. It isn't needed anyway. */
+}
+
+#endif
+
+