[PATCH v2 1/2] smc91x: always use 8-bit access if necessary

Arnd Bergmann arnd at arndb.de
Thu Aug 25 08:39:00 PDT 2016


As Russell King found out the hard way, a change I did to fix multiplatform
builds with this driver broke the old Assabet/Neponset platform: It turns
out that while the driver is runtime configurable in principle, the
runtime configuration does not cover the specific case of machines that
can not do any 16-bit I/O on the smc91x registers.

The driver currently provides helpers to access 16-bit registers for
architectures that are known at compile-time to only have 8-bit I/O,
but my patch changed it to a runtime flag that never gets consulted
most register accesses.

This introduces new SMC_out16()/SMC_in16 helpers (if anyone can suggest
a better name, I'm glad to modify this) that behaves like SMC_outw()/SMC_inw()
most of the time, but uses a pair of 8-bit accesses on platforms that
have no support for wider register accesses.

Signed-off-by: Arnd Bergmann <arnd at arndb.de>
Reported-by: Russell King <linux at armlinux.org.uk>
Fixes: b70661c70830d ("net: smc91x: use run-time configuration on all ARM machines")
---
Having bad luck streak with this patch, the version I sent
had a couple of mistakes from the last rebase before sending
it out, this version should actually apply and build.

diff --git a/drivers/net/ethernet/smsc/smc91x.h b/drivers/net/ethernet/smsc/smc91x.h
index 1a55c7976df0..497411ed6de2 100644
--- a/drivers/net/ethernet/smsc/smc91x.h
+++ b/drivers/net/ethernet/smsc/smc91x.h
@@ -414,30 +414,32 @@ smc_pxa_dma_insw(void __iomem *ioaddr, struct smc_local *lp, int reg, int dma,
 #define SMC_outsl(a, r, p, l)		BUG()
 #endif
 
-#if ! SMC_CAN_USE_16BIT
-
 /*
- * Any 16-bit access is performed with two 8-bit accesses if the hardware
- * can't do it directly. Most registers are 16-bit so those are mandatory.
+ * Any 16-bit register access is performed with two 8-bit accesses if the
+ * hardware can't do it directly.
  */
-#define SMC_outw(x, ioaddr, reg)					\
-	do {								\
-		unsigned int __val16 = (x);				\
-		SMC_outb( __val16, ioaddr, reg );			\
-		SMC_outb( __val16 >> 8, ioaddr, reg + (1 << SMC_IO_SHIFT));\
-	} while (0)
-#define SMC_inw(ioaddr, reg)						\
-	({								\
-		unsigned int __val16;					\
-		__val16 =  SMC_inb( ioaddr, reg );			\
+#define SMC_out16(x, ioaddr, reg)					     \
+do {									     \
+	if (SMC_CAN_USE_8BIT && !SMC_16BIT(lp)) {			     \
+		unsigned int __val16 = (x);				     \
+		SMC_outb(__val16, ioaddr, reg );			     \
+		SMC_outb(__val16 >> 8, ioaddr, reg + (1 << SMC_IO_SHIFT));   \
+	} else {							     \
+		SMC_outw(x, ioaddr, reg);				     \
+	}								     \
+} while (0)
+
+#define SMC_in16(ioaddr, reg)						     \
+({									     \
+	unsigned int __val16;					   	     \
+	if (SMC_CAN_USE_8BIT && !SMC_16BIT(lp)) {			     \
+		__val16 =  SMC_inb( ioaddr, reg );			     \
 		__val16 |= SMC_inb( ioaddr, reg + (1 << SMC_IO_SHIFT)) << 8; \
-		__val16;						\
-	})
-
-#define SMC_insw(a, r, p, l)		BUG()
-#define SMC_outsw(a, r, p, l)		BUG()
-
-#endif
+	} else {							     \
+		__val16 = SMC_inw(ioaddr, reg);				     \
+	}								     \
+	__val16;							     \
+})
 
 #if !defined(SMC_insw) || !defined(SMC_outsw)
 #define SMC_insw(a, r, p, l)		BUG()
@@ -927,113 +929,113 @@ static const char * chip_ids[ 16 ] =  {
 			SMC_outw((x) << 8, ioaddr, INT_REG(lp));	\
 	} while (0)
 
-#define SMC_CURRENT_BANK(lp)	SMC_inw(ioaddr, BANK_SELECT)
+#define SMC_CURRENT_BANK(lp)	SMC_in16(ioaddr, BANK_SELECT)
 
 #define SMC_SELECT_BANK(lp, x)					\
 	do {								\
 		if (SMC_MUST_ALIGN_WRITE(lp))				\
 			SMC_outl((x)<<16, ioaddr, 12<<SMC_IO_SHIFT);	\
 		else							\
-			SMC_outw(x, ioaddr, BANK_SELECT);		\
+			SMC_out16(x, ioaddr, BANK_SELECT);		\
 	} while (0)
 
-#define SMC_GET_BASE(lp)		SMC_inw(ioaddr, BASE_REG(lp))
+#define SMC_GET_BASE(lp)	SMC_in16(ioaddr, BASE_REG(lp))
 
-#define SMC_SET_BASE(lp, x)		SMC_outw(x, ioaddr, BASE_REG(lp))
+#define SMC_SET_BASE(lp, x)	SMC_out16(x, ioaddr, BASE_REG(lp))
 
-#define SMC_GET_CONFIG(lp)	SMC_inw(ioaddr, CONFIG_REG(lp))
+#define SMC_GET_CONFIG(lp)	SMC_in16(ioaddr, CONFIG_REG(lp))
 
-#define SMC_SET_CONFIG(lp, x)	SMC_outw(x, ioaddr, CONFIG_REG(lp))
+#define SMC_SET_CONFIG(lp, x)	SMC_out16(x, ioaddr, CONFIG_REG(lp))
 
-#define SMC_GET_COUNTER(lp)	SMC_inw(ioaddr, COUNTER_REG(lp))
+#define SMC_GET_COUNTER(lp)	SMC_in16(ioaddr, COUNTER_REG(lp))
 
-#define SMC_GET_CTL(lp)		SMC_inw(ioaddr, CTL_REG(lp))
+#define SMC_GET_CTL(lp)		SMC_in16(ioaddr, CTL_REG(lp))
 
-#define SMC_SET_CTL(lp, x)		SMC_outw(x, ioaddr, CTL_REG(lp))
+#define SMC_SET_CTL(lp, x)	SMC_out16(x, ioaddr, CTL_REG(lp))
 
-#define SMC_GET_MII(lp)		SMC_inw(ioaddr, MII_REG(lp))
+#define SMC_GET_MII(lp)		SMC_in16(ioaddr, MII_REG(lp))
 
-#define SMC_GET_GP(lp)		SMC_inw(ioaddr, GP_REG(lp))
+#define SMC_GET_GP(lp)		SMC_in16(ioaddr, GP_REG(lp))
 
 #define SMC_SET_GP(lp, x)						\
 	do {								\
 		if (SMC_MUST_ALIGN_WRITE(lp))				\
 			SMC_outl((x)<<16, ioaddr, SMC_REG(lp, 8, 1));	\
 		else							\
-			SMC_outw(x, ioaddr, GP_REG(lp));		\
+			SMC_out16(x, ioaddr, GP_REG(lp));		\
 	} while (0)
 
-#define SMC_SET_MII(lp, x)		SMC_outw(x, ioaddr, MII_REG(lp))
+#define SMC_SET_MII(lp, x)	SMC_out16(x, ioaddr, MII_REG(lp))
 
-#define SMC_GET_MIR(lp)		SMC_inw(ioaddr, MIR_REG(lp))
+#define SMC_GET_MIR(lp)		SMC_in16(ioaddr, MIR_REG(lp))
 
-#define SMC_SET_MIR(lp, x)		SMC_outw(x, ioaddr, MIR_REG(lp))
+#define SMC_SET_MIR(lp, x)	SMC_out16(x, ioaddr, MIR_REG(lp))
 
-#define SMC_GET_MMU_CMD(lp)	SMC_inw(ioaddr, MMU_CMD_REG(lp))
+#define SMC_GET_MMU_CMD(lp)	SMC_in16(ioaddr, MMU_CMD_REG(lp))
 
-#define SMC_SET_MMU_CMD(lp, x)	SMC_outw(x, ioaddr, MMU_CMD_REG(lp))
+#define SMC_SET_MMU_CMD(lp, x)	SMC_out16(x, ioaddr, MMU_CMD_REG(lp))
 
-#define SMC_GET_FIFO(lp)		SMC_inw(ioaddr, FIFO_REG(lp))
+#define SMC_GET_FIFO(lp)	SMC_in16(ioaddr, FIFO_REG(lp))
 
-#define SMC_GET_PTR(lp)		SMC_inw(ioaddr, PTR_REG(lp))
+#define SMC_GET_PTR(lp)		SMC_in16(ioaddr, PTR_REG(lp))
 
 #define SMC_SET_PTR(lp, x)						\
 	do {								\
 		if (SMC_MUST_ALIGN_WRITE(lp))				\
 			SMC_outl((x)<<16, ioaddr, SMC_REG(lp, 4, 2));	\
 		else							\
-			SMC_outw(x, ioaddr, PTR_REG(lp));		\
+			SMC_out16(x, ioaddr, PTR_REG(lp));		\
 	} while (0)
 
-#define SMC_GET_EPH_STATUS(lp)	SMC_inw(ioaddr, EPH_STATUS_REG(lp))
+#define SMC_GET_EPH_STATUS(lp)	SMC_in16(ioaddr, EPH_STATUS_REG(lp))
 
-#define SMC_GET_RCR(lp)		SMC_inw(ioaddr, RCR_REG(lp))
+#define SMC_GET_RCR(lp)		SMC_in16(ioaddr, RCR_REG(lp))
 
-#define SMC_SET_RCR(lp, x)		SMC_outw(x, ioaddr, RCR_REG(lp))
+#define SMC_SET_RCR(lp, x)	SMC_out16(x, ioaddr, RCR_REG(lp))
 
-#define SMC_GET_REV(lp)		SMC_inw(ioaddr, REV_REG(lp))
+#define SMC_GET_REV(lp)		SMC_in16(ioaddr, REV_REG(lp))
 
-#define SMC_GET_RPC(lp)		SMC_inw(ioaddr, RPC_REG(lp))
+#define SMC_GET_RPC(lp)		SMC_in16(ioaddr, RPC_REG(lp))
 
 #define SMC_SET_RPC(lp, x)						\
 	do {								\
 		if (SMC_MUST_ALIGN_WRITE(lp))				\
 			SMC_outl((x)<<16, ioaddr, SMC_REG(lp, 8, 0));	\
 		else							\
-			SMC_outw(x, ioaddr, RPC_REG(lp));		\
+			SMC_out16(x, ioaddr, RPC_REG(lp));		\
 	} while (0)
 
-#define SMC_GET_TCR(lp)		SMC_inw(ioaddr, TCR_REG(lp))
+#define SMC_GET_TCR(lp)		SMC_in16(ioaddr, TCR_REG(lp))
 
-#define SMC_SET_TCR(lp, x)		SMC_outw(x, ioaddr, TCR_REG(lp))
+#define SMC_SET_TCR(lp, x)	SMC_out16(x, ioaddr, TCR_REG(lp))
 
 #ifndef SMC_GET_MAC_ADDR
 #define SMC_GET_MAC_ADDR(lp, addr)					\
 	do {								\
 		unsigned int __v;					\
-		__v = SMC_inw(ioaddr, ADDR0_REG(lp));			\
+		__v = SMC_in16(ioaddr, ADDR0_REG(lp));			\
 		addr[0] = __v; addr[1] = __v >> 8;			\
-		__v = SMC_inw(ioaddr, ADDR1_REG(lp));			\
+		__v = SMC_in16(ioaddr, ADDR1_REG(lp));			\
 		addr[2] = __v; addr[3] = __v >> 8;			\
-		__v = SMC_inw(ioaddr, ADDR2_REG(lp));			\
+		__v = SMC_in16(ioaddr, ADDR2_REG(lp));			\
 		addr[4] = __v; addr[5] = __v >> 8;			\
 	} while (0)
 #endif
 
 #define SMC_SET_MAC_ADDR(lp, addr)					\
 	do {								\
-		SMC_outw(addr[0]|(addr[1] << 8), ioaddr, ADDR0_REG(lp)); \
-		SMC_outw(addr[2]|(addr[3] << 8), ioaddr, ADDR1_REG(lp)); \
-		SMC_outw(addr[4]|(addr[5] << 8), ioaddr, ADDR2_REG(lp)); \
+		SMC_out16(addr[0]|(addr[1] << 8), ioaddr, ADDR0_REG(lp)); \
+		SMC_out16(addr[2]|(addr[3] << 8), ioaddr, ADDR1_REG(lp)); \
+		SMC_out16(addr[4]|(addr[5] << 8), ioaddr, ADDR2_REG(lp)); \
 	} while (0)
 
 #define SMC_SET_MCAST(lp, x)						\
 	do {								\
 		const unsigned char *mt = (x);				\
-		SMC_outw(mt[0] | (mt[1] << 8), ioaddr, MCAST_REG1(lp)); \
-		SMC_outw(mt[2] | (mt[3] << 8), ioaddr, MCAST_REG2(lp)); \
-		SMC_outw(mt[4] | (mt[5] << 8), ioaddr, MCAST_REG3(lp)); \
-		SMC_outw(mt[6] | (mt[7] << 8), ioaddr, MCAST_REG4(lp)); \
+		SMC_out16(mt[0] | (mt[1] << 8), ioaddr, MCAST_REG1(lp)); \
+		SMC_out16(mt[2] | (mt[3] << 8), ioaddr, MCAST_REG2(lp)); \
+		SMC_out16(mt[4] | (mt[5] << 8), ioaddr, MCAST_REG3(lp)); \
+		SMC_out16(mt[6] | (mt[7] << 8), ioaddr, MCAST_REG4(lp)); \
 	} while (0)
 
 #define SMC_PUT_PKT_HDR(lp, status, length)				\
@@ -1042,8 +1044,8 @@ static const char * chip_ids[ 16 ] =  {
 			SMC_outl((status) | (length)<<16, ioaddr,	\
 				 DATA_REG(lp));			\
 		else {							\
-			SMC_outw(status, ioaddr, DATA_REG(lp));	\
-			SMC_outw(length, ioaddr, DATA_REG(lp));	\
+			SMC_out16(status, ioaddr, DATA_REG(lp));	\
+			SMC_out16(length, ioaddr, DATA_REG(lp));	\
 		}							\
 	} while (0)
 
@@ -1054,8 +1056,8 @@ static const char * chip_ids[ 16 ] =  {
 			(status) = __val & 0xffff;			\
 			(length) = __val >> 16;				\
 		} else {						\
-			(status) = SMC_inw(ioaddr, DATA_REG(lp));	\
-			(length) = SMC_inw(ioaddr, DATA_REG(lp));	\
+			(status) = SMC_in16(ioaddr, DATA_REG(lp));	\
+			(length) = SMC_in16(ioaddr, DATA_REG(lp));	\
 		}							\
 	} while (0)
 




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