pata_mpc52xx: reduce code size by simple change of constant data types
I've prepared a totally simple patch that, if I did it and measured it
correctly, reduces the text size as of the ppc-6xx-size command of
pata-mpc52xx by more than 10%, by reducing the rodata size from 0x4a4
to 0x17e bytes. This is simply done by changing the data types of the
ATA timing constants.
If you are interested at all, and it's worth the trouble, here the
details:
ppc-6xx-size:
text data bss dec hex filename
old: 6532 1068 0 7600 1db0 pata-mpc52xx.o
new: 5718 1068 0 6786 1a82 pata-mpc52xx.o
The (assembler) code itself doesn't really change very much. I double
checked the final results inside mpc52xx-ata-apply-timings() and they
match. The driver is still working fine of course.
Signed-off-by: Roman Fietze <roman.fietze@telemotive.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/pata_mpc52xx.c b/drivers/ata/pata_mpc52xx.c
index 9f5b053..96b11b6 100644
--- a/drivers/ata/pata_mpc52xx.c
+++ b/drivers/ata/pata_mpc52xx.c
@@ -64,13 +64,13 @@
/* ATAPI-4 PIO specs (in ns) */
-static const int ataspec_t0[5] = {600, 383, 240, 180, 120};
-static const int ataspec_t1[5] = { 70, 50, 30, 30, 25};
-static const int ataspec_t2_8[5] = {290, 290, 290, 80, 70};
-static const int ataspec_t2_16[5] = {165, 125, 100, 80, 70};
-static const int ataspec_t2i[5] = { 0, 0, 0, 70, 25};
-static const int ataspec_t4[5] = { 30, 20, 15, 10, 10};
-static const int ataspec_ta[5] = { 35, 35, 35, 35, 35};
+static const u16 ataspec_t0[5] = {600, 383, 240, 180, 120};
+static const u16 ataspec_t1[5] = { 70, 50, 30, 30, 25};
+static const u16 ataspec_t2_8[5] = {290, 290, 290, 80, 70};
+static const u16 ataspec_t2_16[5] = {165, 125, 100, 80, 70};
+static const u16 ataspec_t2i[5] = { 0, 0, 0, 70, 25};
+static const u16 ataspec_t4[5] = { 30, 20, 15, 10, 10};
+static const u16 ataspec_ta[5] = { 35, 35, 35, 35, 35};
#define CALC_CLKCYC(c,v) ((((v)+(c)-1)/(c)))
@@ -78,13 +78,13 @@
/* ATAPI-4 MDMA specs (in clocks) */
struct mdmaspec {
- u32 t0M;
- u32 td;
- u32 th;
- u32 tj;
- u32 tkw;
- u32 tm;
- u32 tn;
+ u8 t0M;
+ u8 td;
+ u8 th;
+ u8 tj;
+ u8 tkw;
+ u8 tm;
+ u8 tn;
};
static const struct mdmaspec mdmaspec66[3] = {
@@ -101,23 +101,23 @@
/* ATAPI-4 UDMA specs (in clocks) */
struct udmaspec {
- u32 tcyc;
- u32 t2cyc;
- u32 tds;
- u32 tdh;
- u32 tdvs;
- u32 tdvh;
- u32 tfs;
- u32 tli;
- u32 tmli;
- u32 taz;
- u32 tzah;
- u32 tenv;
- u32 tsr;
- u32 trfs;
- u32 trp;
- u32 tack;
- u32 tss;
+ u8 tcyc;
+ u8 t2cyc;
+ u8 tds;
+ u8 tdh;
+ u8 tdvs;
+ u8 tdvh;
+ u8 tfs;
+ u8 tli;
+ u8 tmli;
+ u8 taz;
+ u8 tzah;
+ u8 tenv;
+ u8 tsr;
+ u8 trfs;
+ u8 trp;
+ u8 tack;
+ u8 tss;
};
static const struct udmaspec udmaspec66[6] = {
@@ -270,7 +270,7 @@
{
struct mpc52xx_ata_timings *timing = &priv->timings[dev];
unsigned int ipb_period = priv->ipb_period;
- unsigned int t0, t1, t2_8, t2_16, t2i, t4, ta;
+ u32 t0, t1, t2_8, t2_16, t2i, t4, ta;
if ((pio < 0) || (pio > 4))
return -EINVAL;
@@ -299,8 +299,8 @@
if (speed < 0 || speed > 2)
return -EINVAL;
- t->mdma1 = (s->t0M << 24) | (s->td << 16) | (s->tkw << 8) | (s->tm);
- t->mdma2 = (s->th << 24) | (s->tj << 16) | (s->tn << 8);
+ t->mdma1 = ((u32)s->t0M << 24) | ((u32)s->td << 16) | ((u32)s->tkw << 8) | s->tm;
+ t->mdma2 = ((u32)s->th << 24) | ((u32)s->tj << 16) | ((u32)s->tn << 8);
t->using_udma = 0;
return 0;
@@ -316,11 +316,11 @@
if (speed < 0 || speed > 2)
return -EINVAL;
- t->udma1 = (s->t2cyc << 24) | (s->tcyc << 16) | (s->tds << 8) | s->tdh;
- t->udma2 = (s->tdvs << 24) | (s->tdvh << 16) | (s->tfs << 8) | s->tli;
- t->udma3 = (s->tmli << 24) | (s->taz << 16) | (s->tenv << 8) | s->tsr;
- t->udma4 = (s->tss << 24) | (s->trfs << 16) | (s->trp << 8) | s->tack;
- t->udma5 = (s->tzah << 24);
+ t->udma1 = ((u32)s->t2cyc << 24) | ((u32)s->tcyc << 16) | ((u32)s->tds << 8) | s->tdh;
+ t->udma2 = ((u32)s->tdvs << 24) | ((u32)s->tdvh << 16) | ((u32)s->tfs << 8) | s->tli;
+ t->udma3 = ((u32)s->tmli << 24) | ((u32)s->taz << 16) | ((u32)s->tenv << 8) | s->tsr;
+ t->udma4 = ((u32)s->tss << 24) | ((u32)s->trfs << 16) | ((u32)s->trp << 8) | s->tack;
+ t->udma5 = (u32)s->tzah << 24;
t->using_udma = 1;
return 0;