From patchwork Wed Jul 31 09:37:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Kleine-Budde X-Patchwork-Id: 13748381 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A2ED1C3DA7F for ; Wed, 31 Jul 2024 09:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=FmtL/u+dzc/4TpvB+mLX5nOa9W1Rdco0kblxQLsRL60=; b=p1BuqAJWGSDMY89wDZ4mczNtFn xOnZEJYJLDi4Zlkz8Rt0sEEe82ow8b7DLAfnWKbN9uSqHZCp19cfkrT2F30P5ovQkqqpSnL2x7Df5 +SsxGbrBfGJQIAuJcTYvyiXMlX2J4CkBbjkvh5QdXug4J6pMnjdhLiQbqgUOicK5y1D9Pvs3wAi1l 9a4zNqeq7CavDuj/1AG0CkQmAZlt5neiqxN3m4d2rP2PwlEb9LQGCDEinXaKUvSPF3L/3s5jcN/zr DQ0Qr2D3/N8u8pif9Ul8JZJZvT2b/MuoTXJcLzLW9QrmIzNGEEIdx4qHDIravIuB1Uv2PBbmlUs4K lYHnbtdg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZ5qq-00000000Z7G-1Qog; Wed, 31 Jul 2024 09:42:32 +0000 Received: from metis.whiteo.stw.pengutronix.de ([185.203.201.7]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZ5mV-00000000XGt-3qIa for linux-arm-kernel@lists.infradead.org; Wed, 31 Jul 2024 09:38:05 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1sZ5mT-0005f8-AU for linux-arm-kernel@lists.infradead.org; Wed, 31 Jul 2024 11:38:01 +0200 Received: from [2a0a:edc0:0:b01:1d::7b] (helo=bjornoya.blackshift.org) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1sZ5mO-003UnQ-Ev for linux-arm-kernel@lists.infradead.org; Wed, 31 Jul 2024 11:37:56 +0200 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id F3B79312892 for ; Wed, 31 Jul 2024 09:37:55 +0000 (UTC) Received: from hardanger.blackshift.org (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id 553A3312824; Wed, 31 Jul 2024 09:37:52 +0000 (UTC) Received: from [172.20.34.65] (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id d03afc40; Wed, 31 Jul 2024 09:37:42 +0000 (UTC) From: Marc Kleine-Budde Date: Wed, 31 Jul 2024 11:37:11 +0200 Subject: [PATCH can-next v2 09/20] can: rockchip_canfd: rkcanfd_handle_rx_int_one(): implement workaround for erratum 5: check for empty FIFO MIME-Version: 1.0 Message-Id: <20240731-rockchip-canfd-v2-9-d9604c5b4be8@pengutronix.de> References: <20240731-rockchip-canfd-v2-0-d9604c5b4be8@pengutronix.de> In-Reply-To: <20240731-rockchip-canfd-v2-0-d9604c5b4be8@pengutronix.de> To: kernel@pengutronix.de, Vincent Mailhol , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Heiko Stuebner , Philipp Zabel , Elaine Zhang , David Jander Cc: Simon Horman , linux-can@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, Marc Kleine-Budde X-Mailer: b4 0.15-dev-37811 X-Developer-Signature: v=1; a=openpgp-sha256; l=3961; i=mkl@pengutronix.de; h=from:subject:message-id; bh=FLJfTesulV14NYZTiSKDaIDFdma0tMAH3V9sgp4cSYk=; b=owEBbQGS/pANAwAKASg4oj56LbxvAcsmYgBmqgXSdarvWtcVK9HziJ2GGCtOJ8fA+878ggzLp 5YZklxUCAyJATMEAAEKAB0WIQRQQLqG4LYE3Sm8Pl8oOKI+ei28bwUCZqoF0gAKCRAoOKI+ei28 bzsKB/9Hx2M/aV7mVqnLwblChM2517xJLozifL1EMRDG0GxlrKjlVuTdwd6FvzoXluWaSyQqzz9 lARvAq3yAWOWISNpGndNXi1HvOijimXb8MJCTTAAxJYqT8Or/uqEpNQsVZqw+NXGOibgtJN+nzz NizvTiK86Z4Qln/med5QE+ql/QJzf1onZe4f34h9dOI6aoISSMpIxCbF0GThznG0oTLnUCC0CUe ECmyJOEKsoykHamoWGC4oI06nT/tDq/yT9cyLVgxK1NBU4y7QptZU6nDTRtRsZaoPiKD6/RGRYh FwcPt36VpXstp/Y4YtQcbfMlqPV0/snmz6DwBJHLNRQyubHS X-Developer-Key: i=mkl@pengutronix.de; a=openpgp; fpr=C1400BA0B3989E6FBC7D5B5C2B5EE211C58AEA54 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240731_023803_993403_AB256A42 X-CRM114-Status: GOOD ( 20.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The rk3568 CAN-FD errata sheet as of Tue 07 Nov 2023 11:25:31 +08:00 says: | Erratum 5: Counters related to the TXFIFO and RXFIFO exhibit | abnormal counting behavior. | | Due to a bug in the cross-asynchronous logic of the enable signals | for rx_fifo_cnt and txe_fifo_frame_cnt counters, the counts of these | two counters become inaccurate. This issue has resulted in the | inability to use the TXFIFO and RXFIFO functions. The errata sheet mentioned above states that only the rk3568v2 is affected by this erratum, but tests with the rk3568v2 and rk3568v3 show that the RX_FIFO_CNT is sometimes too high. This leads to CAN frames being read from the FIFO, which is then already empty. Further tests on the rk3568v2 and rk3568v3 show that in this situation (i.e. empty FIFO) all elements of the FIFO header (frameinfo, id, ts) contain the same data. On the rk3568v2 and rk3568v3, this problem only occurs extremely rarely with the standard clock of 300 MHz, but almost immediately at 80 MHz. To workaround this problem, check for empty FIFO with rkcanfd_fifo_header_empty() in rkcanfd_handle_rx_int_one() and exit early. Signed-off-by: Marc Kleine-Budde --- drivers/net/can/rockchip/rockchip_canfd-rx.c | 14 ++++++++++++++ drivers/net/can/rockchip/rockchip_canfd.h | 22 ++++++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c index 5398aff0d180..609282359bca 100644 --- a/drivers/net/can/rockchip/rockchip_canfd-rx.c +++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c @@ -47,6 +47,16 @@ rkcanfd_fifo_header_to_cfd_header(const struct rkcanfd_priv *priv, return len + cfd->len; } +static inline bool +rkcanfd_fifo_header_empty(const struct rkcanfd_fifo_header *header) +{ + /* Erratum 5: If the FIFO is empty, we read the same value for + * all elements. + */ + return header->frameinfo == header->id && + header->frameinfo == header->ts; +} + static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv) { struct net_device_stats *stats = &priv->ndev->stats; @@ -63,6 +73,10 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv) rkcanfd_read_rep(priv, RKCANFD_REG_RX_FIFO_RDATA, cfd->data, sizeof(cfd->data)); + /* Erratum 5: Counters for TXEFIFO and RXFIFO may be wrong */ + if (rkcanfd_fifo_header_empty(header)) + return 0; + len = rkcanfd_fifo_header_to_cfd_header(priv, header, cfd); /* Drop any received CAN-FD frames if CAN-FD mode is not diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h index 3dafb5e68dc5..c775e75a2740 100644 --- a/drivers/net/can/rockchip/rockchip_canfd.h +++ b/drivers/net/can/rockchip/rockchip_canfd.h @@ -315,6 +315,28 @@ /* Erratum 5: Counters related to the TXFIFO and RXFIFO exhibit * abnormal counting behavior. + * + * The rk3568 CAN-FD errata sheet as of Tue 07 Nov 2023 11:25:31 +08:00 + * states that only the rk3568v2 is affected by this erratum, but + * tests with the rk3568v2 and rk3568v3 show that the RX_FIFO_CNT is + * sometimes too high. This leads to CAN frames being read from the + * FIFO, which is then already empty. + * + * Further tests on the rk3568v2 and rk3568v3 show that in this + * situation (i.e. empty FIFO) all elements of the FIFO header + * (frameinfo, id, ts) contain the same data. + * + * On the rk3568v2 and rk3568v3, this problem only occurs extremely + * rarely with the standard clock of 300 MHz, but almost immediately + * at 80 MHz. + * + * To workaround this problem, check for empty FIFO with + * rkcanfd_fifo_header_empty() in rkcanfd_handle_rx_int_one() and exit + * early. + * + * To reproduce: + * assigned-clocks = <&cru CLK_CANx>; + * assigned-clock-rates = <80000000>; */ #define RKCANFD_QUIRK_RK3568_ERRATUM_5 BIT(4)