Date: Sat, 29 Jan 2000 22:24:54 +0900 From: YAMAMOTO Shigeru <shigeru@iij.ad.jp> To: dfr@nlsystems.com Cc: imp@village.org, freebsd-hackers@FreeBSD.ORG Subject: Re: how to allocate an alined address for a device? Message-ID: <20000129222454T.shigeru@iij.ad.jp> In-Reply-To: Your message of "Sat, 29 Jan 2000 11:05:47 %2B0000 (GMT)" <Pine.BSF.4.10.10001291105190.25770-100000@salmon.nlsystems.com> References: <Pine.BSF.4.10.10001291105190.25770-100000@salmon.nlsystems.com>
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>>>>> "Doug" == Doug Rabson <Doug> writes:
>> Well, with just 6 bits one could handle any alignment requirement up to
>> 2^(2^6).
>>
>> We have 6 bits left. If this were the alignment requirement, a value of
>> 0 would mean 2^0 or 1, which is the current behavior. More restrictive
>> alignment requirements could be encoded easily. No ABI or API change
>> needed.
>>
>> #define RF_ALIGNMENT_MASK 0xfc00
>> #define RF_ALIGNMENT_SHIFT 10
>> #define RF_ALIGNMENT_LOG2(x) (x << RF_ALIGNMENT_SHIFT)
Doug> That seems reasonable. We should implement this right after 4.0 is
Doug> done.
I re-write a code using Warner's idea.
Thanks,
-------
YAMAMOTO Shigeru Internet Initiative Japan Inc.
<shigeru@iij.ad.jp> Network Engineering Div.
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--- kern/subr_rman.c.org Tue Nov 16 08:28:57 1999
+++ kern/subr_rman.c Sat Jan 29 03:40:36 2000
@@ -227,7 +227,19 @@
continue;
}
rstart = max(s->r_start, start);
- rend = min(s->r_end, max(start + count, end));
+ if (flags & RF_ALIGNMENT_MASK) {
+ /* need to align an address */
+ u_long aligned_rstart;
+ u_long alignment_size;
+
+ alignment_size = (1u << ((flags & RF_ALIGNMENT_MASK) >> RF_ALIGNMENT_SHIFT));
+ aligned_rstart = (rstart & (~alignment_size + 1u));
+ if ((rstart & (~(~alignment_size + 1u))) != 0) {
+ aligned_rstart += alignment_size;
+ }
+ rstart = aligned_rstart;
+ }
+ rend = min(s->r_end, max(max(start + count, end), rstart + count));
#ifdef RMAN_DEBUG
printf("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
rstart, rend, (rend - rstart + 1), count);
@@ -608,4 +620,19 @@
rv = int_rman_release_resource(rm, r);
simple_unlock(rm->rm_slock);
return (rv);
+}
+
+u_int32_t
+rman_make_alignment_flags(int size) {
+ int i;
+
+ for (i = 0; i < 32 && size > 0x01; i ++) {
+ size = (size >> 1);
+ }
+
+ if (i > 31) {
+ i = 0;
+ }
+
+ return(RF_ALIGNMENT_LOG2(i));
}
--- sys/rman.h.org Mon Jan 10 08:48:52 2000
+++ sys/rman.h Sat Jan 29 03:44:40 2000
@@ -64,7 +64,11 @@
#define RF_WANTED 0x0010 /* somebody is waiting for this resource */
#define RF_FIRSTSHARE 0x0020 /* first in sharing list */
-#define RF_PCCARD_ATTR 0x10000 /* PCCARD attribute memory */
+#define RF_PCCARD_ATTR 0x10000 /* PCCARD attribute memory */
+
+#define RF_ALIGNMENT_SHIFT 10 /* alignment size bit starts bit 10 */
+#define RF_ALIGNMENT_MASK (0x003F << RF_ALIGNMENT_SHIFT) /* resource address alignemnt size bit mask */
+#define RF_ALIGNMENT_LOG2(x) ((x) << RF_ALIGNMENT_SHIFT)
enum rman_type { RMAN_UNINIT = 0, RMAN_GAUGE, RMAN_ARRAY };
@@ -91,6 +95,8 @@
struct resource *rman_reserve_resource(struct rman *rm, u_long start,
u_long end, u_long count,
u_int flags, struct device *dev);
+
+extern u_int32_t rman_make_alignment_flags __P((int size));
#define rman_get_start(r) ((r)->r_start)
#define rman_get_end(r) ((r)->r_end)
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