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 9A03A3603DE for ; Sat, 28 Feb 2026 17:48:36 +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=1772300916; cv=none; b=OPIUuDSqJRkxSGWl00pB8gdK9mTIN5wSxBwbJny8/hxa0LvjHOk94rHfxTEP+4G08z8G/3QOg05O7A2KoNcRBeri4FQgpWJyUnXh73jOkZHRYd9V05YKyJ90qjtAJdIVGnSkadcCzGOk/8H5njzVIQAEqjpaRZQ+EnDZH6M42M8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300916; c=relaxed/simple; bh=iv7VVudKM1I3hlT9k5+PCMCP6tgXzG9LZ2Dv/FdCcbk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fUUx98g050mF7ZeqcWH6k3bbje7SthufNLdBdsBZBq+4SV9bkgn9WkJDBq2iQVtenfwiHOTaQnu0YxT70RaIIih4qTGPakqU3IMAdo6vW8ohyosUhPT1Vz9qxwdCHXuHY9NZVPnj7ytINixloc2L5GJ5MTrKWPaDXmiCZ4kmoew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OCW5rLNP; 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="OCW5rLNP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7F27C116D0; Sat, 28 Feb 2026 17:48:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300916; bh=iv7VVudKM1I3hlT9k5+PCMCP6tgXzG9LZ2Dv/FdCcbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OCW5rLNP3wbpd4tDunrjjKrzRoEiBOYCgTg+DbndZEwqSqX/lgYqV3VAcPG+9gpI9 e83aaindbgdimGcMCXcoDD17i2Dqna2A5Ss6rIgOTypWP2dJvuU/d7XucVUbeZdSID 3oQFPBT944XUoQApRLYK9IPppVwLFwRxTfmRYWPTpXaEy6twkmSkMtgCLeXQNScwsy D8RZ+O4t/KXOaIQWkpOqUnkJUD8s5u2sMDiEulJ+BiB5Yv/1VYBl+7qIHXg6Pf4m3r f8ZRtpfrxuluaDExJxtjOsgH3QT6V4l0dguPvZBTYLHxHf0BlOkxcT/FLztoMBOryb HzRytuH1OMmoQ== From: Sasha Levin To: patches@lists.linux.dev Cc: Adrian Hunter , Frank Li , Alexandre Belloni , Sasha Levin Subject: [PATCH 6.18 032/752] i3c: mipi-i3c-hci: Reset RING_OPERATION1 fields during init Date: Sat, 28 Feb 2026 12:35:43 -0500 Message-ID: <20260228174750.1542406-32-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228174750.1542406-1-sashal@kernel.org> References: <20260228174750.1542406-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Adrian Hunter [ Upstream commit 78f63ae4a82db173f93adca462e63d11ba06b126 ] The MIPI I3C HCI specification does not define reset values for RING_OPERATION1 fields, and some controllers (e.g., Intel) do not clear them during a software reset. Ensure the ring pointers are explicitly set to zero during bus initialization to avoid inconsistent state. Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260113072702.16268-2-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin --- drivers/i3c/master/mipi-i3c-hci/dma.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c index c401a9425cdc5..951abfea5a6fd 100644 --- a/drivers/i3c/master/mipi-i3c-hci/dma.c +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c @@ -342,6 +342,14 @@ static int hci_dma_init(struct i3c_hci *hci) rh_reg_write(INTR_SIGNAL_ENABLE, regval); ring_ready: + /* + * The MIPI I3C HCI specification does not document reset values for + * RING_OPERATION1 fields and some controllers (e.g. Intel controllers) + * do not reset the values, so ensure the ring pointers are set to zero + * here. + */ + rh_reg_write(RING_OPERATION1, 0); + rh_reg_write(RING_CONTROL, RING_CTRL_ENABLE | RING_CTRL_RUN_STOP); } -- 2.51.0