Thread (7 messages) flat view 7 messages, 3 authors, 2016-06-27
STALE3703d REVIEWED: 1 (1M)

1 review trailer.

[PATCH net-next 2/5] phy: convert swphy register generation to tabular form

From: Russell King <hidden>
Date: 2016-06-23 13:50:14
Subsystem: ethernet phy library, networking drivers, the rest · Maintainers: Andrew Lunn, Heiner Kallweit, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

Convert the swphy register generation to tabular form which allows us
to eliminate multiple switch() statements.  This results in a smaller
object code size, more efficient, and easier to add support for faster
speeds.

Before:

Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00000164  00000000  00000000  00000034  2**2

   text    data     bss     dec     hex filename
    388       0       0     388     184 swphy.o

After:

Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         000000fc  00000000  00000000  00000034  2**2
  5 .rodata       00000028  00000000  00000000  00000138  2**2

   text    data     bss     dec     hex filename
    324       0       0     324     144 swphy.o

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <redacted>
---
 drivers/net/phy/swphy.c | 143 ++++++++++++++++++++++++++----------------------
 1 file changed, 78 insertions(+), 65 deletions(-)
diff --git a/drivers/net/phy/swphy.c b/drivers/net/phy/swphy.c
index 0551a79a2454..c88a194b4cb6 100644
--- a/drivers/net/phy/swphy.c
+++ b/drivers/net/phy/swphy.c
@@ -20,6 +20,72 @@
 
 #include "swphy.h"
 
+struct swmii_regs {
+	u16 bmcr;
+	u16 bmsr;
+	u16 lpa;
+	u16 lpagb;
+};
+
+enum {
+	SWMII_SPEED_10 = 0,
+	SWMII_SPEED_100,
+	SWMII_SPEED_1000,
+	SWMII_DUPLEX_HALF = 0,
+	SWMII_DUPLEX_FULL,
+};
+
+/*
+ * These two tables get bitwise-anded together to produce the final result.
+ * This means the speed table must contain both duplex settings, and the
+ * duplex table must contain all speed settings.
+ */
+static const struct swmii_regs speed[] = {
+	[SWMII_SPEED_10] = {
+		.bmcr  = BMCR_FULLDPLX,
+		.lpa   = LPA_10FULL | LPA_10HALF,
+	},
+	[SWMII_SPEED_100] = {
+		.bmcr  = BMCR_FULLDPLX | BMCR_SPEED100,
+		.bmsr  = BMSR_100FULL | BMSR_100HALF,
+		.lpa   = LPA_100FULL | LPA_100HALF,
+	},
+	[SWMII_SPEED_1000] = {
+		.bmcr  = BMCR_FULLDPLX | BMCR_SPEED1000,
+		.bmsr  = BMSR_ESTATEN,
+		.lpagb = LPA_1000FULL | LPA_1000HALF,
+	},
+};
+
+static const struct swmii_regs duplex[] = {
+	[SWMII_DUPLEX_HALF] = {
+		.bmcr  = ~BMCR_FULLDPLX,
+		.bmsr  = BMSR_ESTATEN | BMSR_100HALF,
+		.lpa   = LPA_10HALF | LPA_100HALF,
+		.lpagb = LPA_1000HALF,
+	},
+	[SWMII_DUPLEX_FULL] = {
+		.bmcr  = ~0,
+		.bmsr  = BMSR_ESTATEN | BMSR_100FULL,
+		.lpa   = LPA_10FULL | LPA_100FULL,
+		.lpagb = LPA_1000FULL,
+	},
+};
+
+static int swphy_decode_speed(int speed)
+{
+	switch (speed) {
+	case 1000:
+		return SWMII_SPEED_1000;
+	case 100:
+		return SWMII_SPEED_100;
+	case 10:
+		return SWMII_SPEED_10;
+	default:
+		return -EINVAL;
+	}
+}
+
 /**
  * swphy_update_regs - update MII register array with fixed phy state
  * @regs: array of 32 registers to update
@@ -30,81 +96,28 @@
  */
 int swphy_update_regs(u16 *regs, const struct fixed_phy_status *state)
 {
+	int speed_index, duplex_index;
 	u16 bmsr = BMSR_ANEGCAPABLE;
 	u16 bmcr = 0;
 	u16 lpagb = 0;
 	u16 lpa = 0;
 
-	if (state->duplex) {
-		switch (state->speed) {
-		case 1000:
-			bmsr |= BMSR_ESTATEN;
-			break;
-		case 100:
-			bmsr |= BMSR_100FULL;
-			break;
-		case 10:
-			bmsr |= BMSR_10FULL;
-			break;
-		default:
-			break;
-		}
-	} else {
-		switch (state->speed) {
-		case 1000:
-			bmsr |= BMSR_ESTATEN;
-			break;
-		case 100:
-			bmsr |= BMSR_100HALF;
-			break;
-		case 10:
-			bmsr |= BMSR_10HALF;
-			break;
-		default:
-			break;
-		}
+	speed_index = swphy_decode_speed(state->speed);
+	if (speed_index < 0) {
+		pr_warn("swphy: unknown speed\n");
+		return -EINVAL;
 	}
 
+	duplex_index = state->duplex ? SWMII_DUPLEX_FULL : SWMII_DUPLEX_HALF;
+
+	bmsr |= speed[speed_index].bmsr & duplex[duplex_index].bmsr;
+
 	if (state->link) {
 		bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
 
-		if (state->duplex) {
-			bmcr |= BMCR_FULLDPLX;
-
-			switch (state->speed) {
-			case 1000:
-				bmcr |= BMCR_SPEED1000;
-				lpagb |= LPA_1000FULL;
-				break;
-			case 100:
-				bmcr |= BMCR_SPEED100;
-				lpa |= LPA_100FULL;
-				break;
-			case 10:
-				lpa |= LPA_10FULL;
-				break;
-			default:
-				pr_warn("swphy: unknown speed\n");
-				return -EINVAL;
-			}
-		} else {
-			switch (state->speed) {
-			case 1000:
-				bmcr |= BMCR_SPEED1000;
-				lpagb |= LPA_1000HALF;
-				break;
-			case 100:
-				bmcr |= BMCR_SPEED100;
-				lpa |= LPA_100HALF;
-				break;
-			case 10:
-				lpa |= LPA_10HALF;
-				break;
-			default:
-				pr_warn("swphy: unknown speed\n");
-				return -EINVAL;
-			}
-		}
+		bmcr  |= speed[speed_index].bmcr  & duplex[duplex_index].bmcr;
+		lpa   |= speed[speed_index].lpa   & duplex[duplex_index].lpa;
+		lpagb |= speed[speed_index].lpagb & duplex[duplex_index].lpagb;
 
 		if (state->pause)
 			lpa |= LPA_PAUSE_CAP;
-- 
2.1.0
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help