From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC302157A79; Sun, 24 Mar 2024 23:12:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321949; cv=none; b=TIqqVZFCXHjaPYCyWMg94ggzGDJo0HMNPCXOZOs3a0edQbfYKZrxMPHC3GJxJJkvpFKB1YJruidcH00CwCj+32k+l5fJXGFMvoNYWiEZMdvQB9izKZqFsoWakPJqUPriXwYg90uArTcP0bO725An92s/8wnRZEpLeYmjdSGuYmA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321949; c=relaxed/simple; bh=hvQacLUHv2CHEtBQWiQYdrGs6KhvmHzqYnpwsBmzmLg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZZmHeJfOyfrTXJFExaEkloDRTrLdwoEm5HFPme0Wn9w/KWo0Oy2SBiQIJIGrOPGYChARD5crChdW5fUAvYolsdvpcMDZZwTAslL1bmb5ZkUfKCzNEjv4lHSzWmCqcEuOJza73SarfyZBRJrofZQcCiakGTtQQfc7vmESPQsfw10= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i1k+WSrH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="i1k+WSrH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 112F2C433A6; Sun, 24 Mar 2024 23:12:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711321948; bh=hvQacLUHv2CHEtBQWiQYdrGs6KhvmHzqYnpwsBmzmLg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i1k+WSrHfi0YNPxBgnKvrq2DwJHl1/8eSTmMnZyEBEnCJY9WCa1Z6CtvmSGvljX3l CCcP9fn2XALYbcpoQ+pnSA5fXtcFE40v1kUjF8xlsvY/7NF3w1DhEUUX/nqv+2t4p6 ApLS8KiKfaSQgIbiVbLXIXdQIo0KqLtEcx1vlutpwdEybwQvUvSCoqWGOhJNQFb9WX exiKO+pteB0yYmRBRKrvSnk7zmy40S1yQdf7q6GP0mAP+SzWJ6OFO13msWs/xJys73 G9kzVRE1TQ6lQ1kisqJKGYGqUyfEqaeXOVhEGjX1YlZBWrqzV3Z9EnoEpMN/QTdj/0 5iEe6GI+7pRKQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ilkka Koskinen , Robin Murphy , Will Deacon , Sasha Levin Subject: [PATCH 6.1 020/451] perf/arm-cmn: Workaround AmpereOneX errata AC04_MESH_1 (incorrect child count) Date: Sun, 24 Mar 2024 19:04:56 -0400 Message-ID: <20240324231207.1351418-21-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324231207.1351418-1-sashal@kernel.org> References: <20240324231207.1351418-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Ilkka Koskinen [ Upstream commit 50572064ec7109b00eef8880e905f55861c8b3de ] AmpereOneX mesh implementation has a bug in HN-P nodes that makes them report incorrect child count. The failing crosspoints report 8 children while they only have two. When the driver tries to access the inexistent child nodes, it believes it has reached an invalid node type and probing fails. The workaround is to ignore those incorrect child nodes and continue normally. Signed-off-by: Ilkka Koskinen [ rm: rewrote simpler generalised version ] Tested-by: Ilkka Koskinen Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/ce4b1442135fe03d0de41859b04b268c88c854a3.1707498577.git.robin.murphy@arm.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/perf/arm-cmn.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index 47e7c3206939f..899e4ed49905c 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -2178,6 +2178,17 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) dev_dbg(cmn->dev, "ignoring external node %llx\n", reg); continue; } + /* + * AmpereOneX erratum AC04_MESH_1 makes some XPs report a bogus + * child count larger than the number of valid child pointers. + * A child offset of 0 can only occur on CMN-600; otherwise it + * would imply the root node being its own grandchild, which + * we can safely dismiss in general. + */ + if (reg == 0 && cmn->part != PART_CMN600) { + dev_dbg(cmn->dev, "bogus child pointer?\n"); + continue; + } arm_cmn_init_node_info(cmn, reg & CMN_CHILD_NODE_ADDR, dn); -- 2.43.0