Commit c70c4733 authored by Alexey Brodkin's avatar Alexey Brodkin Committed by Vineet Gupta

ARCv2: SLC: Make sure busy bit is set properly on SLC flushing

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.

Cc: stable@vger.kernel.org  #4.10
Signed-off-by: default avatarAlexey Brodkin <abrodkin@synopsys.com>
[vgupta: reworte changelog a bit]
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent ae9955ae
...@@ -633,6 +633,9 @@ noinline static void slc_entire_op(const int op) ...@@ -633,6 +633,9 @@ noinline static void slc_entire_op(const int op)
write_aux_reg(ARC_REG_SLC_INVALIDATE, 1); write_aux_reg(ARC_REG_SLC_INVALIDATE, 1);
/* Make sure "busy" bit reports correct stataus, see STAR 9001165532 */
read_aux_reg(r);
/* Important to wait for flush to complete */ /* Important to wait for flush to complete */
while (read_aux_reg(r) & SLC_CTRL_BUSY); while (read_aux_reg(r) & SLC_CTRL_BUSY);
} }
......
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