This is a note to let you know that I've just added the patch titled ARM: 9007/1: l2c: fix prefetch bits init in L2X0_AUX_CTRL using DT values to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm-9007-1-l2c-fix-prefetch-bits-init-in-l2x0_aux_ct.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 85a02013dfd47a721ac8f5b3e6938678fba5d0b5 Author: Guillaume Tucker <guillaume.tucker@xxxxxxxxxxxxx> Date: Tue Sep 1 16:58:06 2020 +0100 ARM: 9007/1: l2c: fix prefetch bits init in L2X0_AUX_CTRL using DT values [ Upstream commit 8e007b367a59bcdf484c81f6df9bd5a4cc179ca6 ] The L310_PREFETCH_CTRL register bits 28 and 29 to enable data and instruction prefetch respectively can also be accessed via the L2X0_AUX_CTRL register. They appear to be actually wired together in hardware between the registers. Changing them in the prefetch register only will get undone when restoring the aux control register later on. For this reason, set these bits in both registers during initialisation according to the devicetree property values. Link: https://lore.kernel.org/lkml/76f2f3ad5e77e356e0a5b99ceee1e774a2842c25.1597061474.git.guillaume.tucker@xxxxxxxxxxxxx/ Fixes: ec3bd0e68a67 ("ARM: 8391/1: l2c: add options to overwrite prefetching behavior") Signed-off-by: Guillaume Tucker <guillaume.tucker@xxxxxxxxxxxxx> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c index 493692d838c67..0b6f8a93d8c60 100644 --- a/arch/arm/mm/cache-l2x0.c +++ b/arch/arm/mm/cache-l2x0.c @@ -1228,20 +1228,28 @@ static void __init l2c310_of_parse(const struct device_node *np, ret = of_property_read_u32(np, "prefetch-data", &val); if (ret == 0) { - if (val) + if (val) { prefetch |= L310_PREFETCH_CTRL_DATA_PREFETCH; - else + *aux_val |= L310_PREFETCH_CTRL_DATA_PREFETCH; + } else { prefetch &= ~L310_PREFETCH_CTRL_DATA_PREFETCH; + *aux_val &= ~L310_PREFETCH_CTRL_DATA_PREFETCH; + } + *aux_mask &= ~L310_PREFETCH_CTRL_DATA_PREFETCH; } else if (ret != -EINVAL) { pr_err("L2C-310 OF prefetch-data property value is missing\n"); } ret = of_property_read_u32(np, "prefetch-instr", &val); if (ret == 0) { - if (val) + if (val) { prefetch |= L310_PREFETCH_CTRL_INSTR_PREFETCH; - else + *aux_val |= L310_PREFETCH_CTRL_INSTR_PREFETCH; + } else { prefetch &= ~L310_PREFETCH_CTRL_INSTR_PREFETCH; + *aux_val &= ~L310_PREFETCH_CTRL_INSTR_PREFETCH; + } + *aux_mask &= ~L310_PREFETCH_CTRL_INSTR_PREFETCH; } else if (ret != -EINVAL) { pr_err("L2C-310 OF prefetch-instr property value is missing\n"); }