linux-kernel - [PATCH 4.12 42/99] ARCv2: SLC: Make sure busy bit is set properly for region ops

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Date:   Mon, 28 Aug 2017 10:04:40 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Alexey Brodkin <abrodkin@...opsys.com>,
        Vineet Gupta <vgupta@...opsys.com>
Subject: [PATCH 4.12 42/99] ARCv2: SLC: Make sure busy bit is set properly for region ops

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexey Brodkin <abrodkin@...opsys.com>

commit b37174d95b0251611a80ef60abf03752e9d66d67 upstream.

c70c473396cb "ARCv2: SLC: Make sure busy bit is set properly on SLC flushing"
fixes problem for entire SLC operation where the problem was initially
caught. But given a nature of the issue it is perfectly possible for
busy bit to be read incorrectly even when region operation was started.

So extending initial fix for regional operation as well.

Signed-off-by: Alexey Brodkin <abrodkin@...opsys.com>
Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arc/mm/cache.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -697,6 +697,9 @@ noinline void slc_op(phys_addr_t paddr,
 	write_aux_reg(ARC_REG_SLC_RGN_END, (paddr + sz + l2_line_sz - 1));
 	write_aux_reg(ARC_REG_SLC_RGN_START, paddr);
 
+	/* Make sure "busy" bit reports correct stataus, see STAR 9001165532 */
+	read_aux_reg(ARC_REG_SLC_CTRL);
+
 	while (read_aux_reg(ARC_REG_SLC_CTRL) & SLC_CTRL_BUSY);
 
 	spin_unlock_irqrestore(&lock, flags);