As reported in STAR 9001165532, an SLC control reg read (for checking busy state) right after SLC invalidate command may incorrectly return NOT busy causing software to NOT spin-wait while operation is underway. (and for some reason this only happens if L1 cache is also disabled - as required by IOC programming model) Suggested workaround is to do an additional Control Reg read, which ensures the 2nd read gets the right status. Same fix made in Linux kernel: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c70c473396cbdec1168a6eff60e13029c0916854 Signed-off-by: Alexey Brodkin <abrodkin at synopsys.com> --- arch/arc/lib/cache.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arc/lib/cache.c b/arch/arc/lib/cache.c index b6ec83112cd8..f1436bf19992 100644 --- a/arch/arc/lib/cache.c +++ b/arch/arc/lib/cache.c @@ -59,10 +59,16 @@ static unsigned int __before_slc_op(const int op) static void __after_slc_op(const int op, unsigned int reg) { - if (op & OP_FLUSH) /* flush / flush-n-inv both wait */ + if (op & OP_FLUSH) { /* flush / flush-n-inv both wait */ + /* + * Make sure "busy" bit reports correct status, + * see STAR 9001165532 + */ + read_aux_reg(ARC_AUX_SLC_CTRL); while (read_aux_reg(ARC_AUX_SLC_CTRL) & DC_CTRL_FLUSH_STATUS) ; + } /* Switch back to default Invalidate mode */ if (op == OP_INV) -- 2.7.4
