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Commit ada9f1ca authored by Felix Fietkau's avatar Felix Fietkau Committed by John W. Linville
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ath9k_hw: optimize all descriptor access functions 



Because all of the descriptor data structures are marked as __packed, GCC
assumes the worst case wrt. alignment and generates unaligned load/store
instructions on MIPS for access to all fields.
Since descriptors always have to be 4-byte-aligned, we can just mark the
data structures with __aligned(4), which allows GCC to generate much more
efficient code.
Verified through disassembly and OProfile comparisons.

Signed-off-by: default avatarFelix Fietkau <nbd@openwrt.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent f0e94b47

drivers/net/wireless/ath/ath9k/ar9003_mac.h

+3 −3
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ struct ar9003_rxs { 
	u32 status9;

	u32 status10;

	u32 status11;

} __packed;

} __packed __aligned(4);



/* Transmit Control Descriptor */

struct ar9003_txc {
@@ -93,7 +93,7 @@ struct ar9003_txc { 
	u32 ctl21;  /* DMA control 21 */

	u32 ctl22;  /* DMA control 22 */

	u32 pad[9]; /* pad to cache line (128 bytes/32 dwords) */

} __packed;

} __packed __aligned(4);



struct ar9003_txs {

	u32 ds_info;
@@ -105,7 +105,7 @@ struct ar9003_txs { 
	u32 status6;

	u32 status7;

	u32 status8;

} __packed;

} __packed __aligned(4);



void ar9003_hw_attach_mac_ops(struct ath_hw *hw);

void ath9k_hw_set_rx_bufsize(struct ath_hw *ah, u16 buf_size);

drivers/net/wireless/ath/ath9k/mac.h

+2 −2
Original line number Diff line number Diff line
@@ -237,7 +237,7 @@ struct ath_desc { 
	u32 ds_ctl1;

	u32 ds_hw[20];

	void *ds_vdata;

} __packed;

} __packed __aligned(4);



#define ATH9K_TXDESC_CLRDMASK		0x0001

#define ATH9K_TXDESC_NOACK		0x0002
@@ -307,7 +307,7 @@ struct ar5416_desc { 
			u32 status8;

		} rx;

	} u;

} __packed;

} __packed __aligned(4);



#define AR5416DESC(_ds)         ((struct ar5416_desc *)(_ds))

#define AR5416DESC_CONST(_ds)   ((const struct ar5416_desc *)(_ds))