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Commit 1d9e9477 authored by Andrey Smirnov's avatar Andrey Smirnov Committed by Shawn Guo
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ARM: i.MX: system.c: Tweak prefetch settings for performance 



Update Prefetch Control Register settings to match that of Freescale's
Linux tree. As the commit e3addf1b773964eac7f797e8538c69481be4279c
states (author Nitin Garg):

"... set Prefetch offset to 15, since it improves memcpy performance by
35%. Don't enable Incr double Linefill enable since it adversely affects
memcpy performance by about 32MB/s and reads by 90MB/s. Tested with 4K
to 16MB sized src and dst aligned buffer..."

Those results are also corroborated by our own testing.

Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Tested-by: default avatarChris Healy <cphealy@gmail.com>
Signed-off-by: default avatarAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: default avatarShawn Guo <shawnguo@kernel.org>
parent b8290371

arch/arm/mach-imx/system.c

+6 −2
Original line number Diff line number Diff line
@@ -111,8 +111,12 @@ void __init imx_init_l2cache(void) 
		val = readl_relaxed(l2x0_base + L310_PREFETCH_CTRL);

		val |= L310_PREFETCH_CTRL_DBL_LINEFILL |

			L310_PREFETCH_CTRL_INSTR_PREFETCH |

			L310_PREFETCH_CTRL_DATA_PREFETCH |

			L310_PREFETCH_CTRL_DBL_LINEFILL_INCR;

			L310_PREFETCH_CTRL_DATA_PREFETCH;



		/* Set perfetch offset to improve performance */

		val &= ~L310_PREFETCH_CTRL_OFFSET_MASK;

		val |= 15;



		writel_relaxed(val, l2x0_base + L310_PREFETCH_CTRL);

	}