From patchwork Sat Aug 7 13:07:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dario Binacchi X-Patchwork-Id: 493585 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13927C4338F for ; Sat, 7 Aug 2021 13:08:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0D076103B for ; Sat, 7 Aug 2021 13:08:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232291AbhHGNI2 (ORCPT ); Sat, 7 Aug 2021 09:08:28 -0400 Received: from smtp-32.italiaonline.it ([213.209.10.32]:44067 "EHLO libero.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S232207AbhHGNI1 (ORCPT ); Sat, 7 Aug 2021 09:08:27 -0400 Received: from passgat-Modern-14-A10M.homenet.telecomitalia.it ([82.60.87.158]) by smtp-32.iol.local with ESMTPA id CM3WmQm3XPvRTCM3bmIfYk; Sat, 07 Aug 2021 15:08:08 +0200 x-libjamoibt: 1601 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=libero.it; s=s2021; t=1628341688; bh=h42hvfOsVcsxyMi5VYbK7VWGEQ0NFsL2rgTVmpybmxg=; h=From; b=vLOFj436iHwG4y9ulGw15LMD3n4sZmLh/QhYvFT0j/r54aKABMIwgrXpdSyVGtE4N BzaOzZ88bs4csZO4dnol+oTJOMAjB/f0UVEhO/wb/ZByAIBw+YHlKKDMaH3PIyqCjD DgjvzgxeZht+jJsopCBfG/VGyx3SQ64GvVbrHi5ne/DVGJQITKXzePravHbVLqlyj7 1RetIaAAv1jEFLzJdbW4VTSPqGjSp6/TIr5Qd1AmCCOfAy2H7OhRi6JfciJR+jT01D nFGlIkMwAg+x2MQhZYyMHLlh+5ew8VhwD7nALYGpexb1olNwupW8AZC9x39XQInA61 pk0b8y9lY+Ztg== X-CNFS-Analysis: v=2.4 cv=NqgUz+RJ c=1 sm=1 tr=0 ts=610e85b8 cx=a_exe a=Hc/BMeSBGyun2kpB8NmEvQ==:117 a=Hc/BMeSBGyun2kpB8NmEvQ==:17 a=TSeAaTSCjiJB7GOU1roA:9 From: Dario Binacchi To: linux-kernel@vger.kernel.org Cc: Gianluca Falavigna , Dario Binacchi , Andrew Lunn , "David S. Miller" , Jakub Kicinski , Marc Kleine-Budde , Tong Zhang , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v3 1/4] can: c_can: remove struct c_can_priv::priv field Date: Sat, 7 Aug 2021 15:07:57 +0200 Message-Id: <20210807130800.5246-2-dariobin@libero.it> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210807130800.5246-1-dariobin@libero.it> References: <20210807130800.5246-1-dariobin@libero.it> X-CMAE-Envelope: MS4xfFXjyjkSSREEemsSXHD6ghKK6Ear5v3Gm1j9QSAtbp+ZLi0S+dxRbwa1ixcbKnNpPW9G15s+HZxGOUSaQCbbhZ2TQURMi8QBGm6Z54yoHyPdL3QXcVNP BMiNJz8LTXzQtOjmHx2DGyNucM60bl0VQXUxG+aANmgHbpd+u8SoVLDRdxIRLejPEEAuQ6Dvesb6kPHJXQ1G62S0+DikujHvIa9JIBJp/au1CHnHj0GaTiYk u3awC2snpN5WVznLBOIl2MtJsoXQTlWmSO21ILaZAZLvgDD/YWu7/CNWj3DrET0L+X7wVyj6k3sZzENm4o0UPgVdKSLyok8ftZXN4jmTP/M6aleRo+jJok6g ux+9cxLLZa9C2RQpYjqhObEH0vkMkV4cbt2fWjdS0i/24rlrZFzOuTLL0aArxVpALPZ1y6rklrmYRaUInu98FhLsT1HO4kvJhc0ba5yIIATAdUh5ssJhOWtq isYUDbfqV4JrZ8T9GTInV8bx6nq7gWQUs5yBdplHzVH5fU5m8PUIsEykyOyKUMtdBohhlUb1gJ2nweVv Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org It references the clock but it is never used. So let's remove it. Signed-off-by: Dario Binacchi --- (no changes since v1) drivers/net/can/c_can/c_can.h | 1 - drivers/net/can/c_can/c_can_platform.c | 1 - 2 files changed, 2 deletions(-) diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h index 4247ff80a29c..8f23e9c83c84 100644 --- a/drivers/net/can/c_can/c_can.h +++ b/drivers/net/can/c_can/c_can.h @@ -200,7 +200,6 @@ struct c_can_priv { void (*write_reg32)(const struct c_can_priv *priv, enum reg index, u32 val); void __iomem *base; const u16 *regs; - void *priv; /* for board-specific data */ enum c_can_dev_id type; struct c_can_raminit raminit_sys; /* RAMINIT via syscon regmap */ void (*raminit)(const struct c_can_priv *priv, bool enable); diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c index 36950363682f..86e95e9d6533 100644 --- a/drivers/net/can/c_can/c_can_platform.c +++ b/drivers/net/can/c_can/c_can_platform.c @@ -385,7 +385,6 @@ static int c_can_plat_probe(struct platform_device *pdev) priv->base = addr; priv->device = &pdev->dev; priv->can.clock.freq = clk_get_rate(clk); - priv->priv = clk; priv->type = drvdata->id; platform_set_drvdata(pdev, dev); From patchwork Sat Aug 7 13:07:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dario Binacchi X-Patchwork-Id: 493817 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF831C432BE for ; Sat, 7 Aug 2021 13:09:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9B116103B for ; Sat, 7 Aug 2021 13:09:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232348AbhHGNJ2 (ORCPT ); Sat, 7 Aug 2021 09:09:28 -0400 Received: from smtp-32.italiaonline.it ([213.209.10.32]:44067 "EHLO libero.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S232226AbhHGNJZ (ORCPT ); Sat, 7 Aug 2021 09:09:25 -0400 Received: from passgat-Modern-14-A10M.homenet.telecomitalia.it ([82.60.87.158]) by smtp-32.iol.local with ESMTPA id CM3WmQm3XPvRTCM3cmIfZ4; Sat, 07 Aug 2021 15:08:08 +0200 x-libjamoibt: 1601 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=libero.it; s=s2021; t=1628341688; bh=qcQQKkpQcTduRVA/CnmRQITGUWlSeT/brnZTnXQ+50c=; h=From; b=gNXMP5g8mcUSeTr+UsiRu0FcPlG8lvMhLc0HivVzUtgdjJnMjCu4FdIHqXnSoXjEO /9RPyLU6Pkcpcl8HVre90o9A3yDkjxGYqOdby9OClniPRYvJj2zgFGBi7kHFHgY4SB LTeoRuCdpeNJwsth9cKDAc9JITooyUOoB/huDjK9PRuuRpz2mpfaSz4Iu4Gfo4fKyE RmqMFY0Oy7i+Tc39BmJcBGOCjdEWc1SeKZdFuDKG1782SrW2M0JwQo2NFYFFlzAJOP sTnZXyE07cfEBM16eSkNAs9spuxTB+CMGMDjIM+3o1kV1oySKbb7ZYTCatB+g6wAt+ 9UcRdy6U70uvw== X-CNFS-Analysis: v=2.4 cv=NqgUz+RJ c=1 sm=1 tr=0 ts=610e85b8 cx=a_exe a=Hc/BMeSBGyun2kpB8NmEvQ==:117 a=Hc/BMeSBGyun2kpB8NmEvQ==:17 a=0RFnQWo-as75lT-uasUA:9 From: Dario Binacchi To: linux-kernel@vger.kernel.org Cc: Gianluca Falavigna , Dario Binacchi , "David S. Miller" , Jakub Kicinski , Marc Kleine-Budde , Oliver Hartkopp , Vincent Mailhol , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v3 2/4] can: c_can: exit c_can_do_tx() early if no frames have been sent Date: Sat, 7 Aug 2021 15:07:58 +0200 Message-Id: <20210807130800.5246-3-dariobin@libero.it> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210807130800.5246-1-dariobin@libero.it> References: <20210807130800.5246-1-dariobin@libero.it> X-CMAE-Envelope: MS4xfFXjyjkSSREEemsSXHD6ghKK6Ear5v3Gm1j9QSAtbp+ZLi0S+dxRbwa1ixcbKnNpPW9G15s+HZxGOUSaQCbbhZ2TQURMi8QBGm6Z54yoHyPdL3QXcVNP BMiNJz8LTXzQtOjmHx2DGyNucM60bl0VQXUxG+aANmgHbpd+u8SoVLDRdxIRLejPEEAuQ6Dvesb6kPHJXQ1G62S0+DikujHvIa9JIBJp/au1CHnHj0GaTiYk u3awC2snpN5WVznLBOIl2MtJsoXQTlWmSO21ILaZAZIG5STGS9UynV5JU2q36XwSkwxDzksuO5lljJSLcZMaKaZbpGCMivkE53WDJv6aWD3LtEyIMHJ0uTHm wm5LnBnqugQ84EiBwQMO+9Orm7GNuv9d9G8t+xFWuDmhvBKlaXnp5oXhBiRrbwbaQrPuIEkVD2+h+DYNdOKsqVSyu7W/w1I2OEdZ8qhlIEvfRHuaqf3eddtR /iVFbBCI4vTJxx4+OERoF/OmDUMV+C+iFNWC0LDzARgSe0gVeQV3VthKNrjPtuP4+d8nDd+r7Jub3F14t/Ep2kD8M6A8Po8oWjNxhg== Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The c_can_poll() handles RX/TX events unconditionally. It may therefore happen that c_can_do_tx() is called unnecessarily because the interrupt was triggered by the reception of a frame. In these cases, we avoid to execute unnecessary statements and exit immediately. Signed-off-by: Dario Binacchi --- (no changes since v1) drivers/net/can/c_can/c_can_main.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c index 7588f70ca0fe..fec0e3416970 100644 --- a/drivers/net/can/c_can/c_can_main.c +++ b/drivers/net/can/c_can/c_can_main.c @@ -720,17 +720,18 @@ static void c_can_do_tx(struct net_device *dev) pkts++; } + if (!pkts) + return; + /* Clear the bits in the tx_active mask */ atomic_sub(clr, &priv->tx_active); if (clr & BIT(priv->msg_obj_tx_num - 1)) netif_wake_queue(dev); - if (pkts) { - stats->tx_bytes += bytes; - stats->tx_packets += pkts; - can_led_event(dev, CAN_LED_EVENT_TX); - } + stats->tx_bytes += bytes; + stats->tx_packets += pkts; + can_led_event(dev, CAN_LED_EVENT_TX); } /* If we have a gap in the pending bits, that means we either From patchwork Sat Aug 7 13:07:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dario Binacchi X-Patchwork-Id: 493816 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2584C4338F for ; Sat, 7 Aug 2021 13:09:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D256460295 for ; Sat, 7 Aug 2021 13:09:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232176AbhHGNJh (ORCPT ); Sat, 7 Aug 2021 09:09:37 -0400 Received: from smtp-32.italiaonline.it ([213.209.10.32]:42629 "EHLO libero.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S232321AbhHGNJ1 (ORCPT ); Sat, 7 Aug 2021 09:09:27 -0400 Received: from passgat-Modern-14-A10M.homenet.telecomitalia.it ([82.60.87.158]) by smtp-32.iol.local with ESMTPA id CM3WmQm3XPvRTCM3cmIfZG; Sat, 07 Aug 2021 15:08:09 +0200 x-libjamoibt: 1601 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=libero.it; s=s2021; t=1628341689; bh=E6M7RVWVJWpQmUiLkb81pv+TQOaxLq5ahfz354xgFLU=; h=From; b=mKTQUwVVq5mESSisyjCNpHVLxbuLvaGmt/iBPePNyO7dSew5RUP51IKI5Lmxyfmgr CNJhAkqwDJTD1JHlIx/Ej+s97RGkrnk6PO4R1ZZKWgWOyc1Seh5sHKltm818hp+p6Z djBPDkELgic/X85EaLfrfbxYJQZYzpxWMA0NBkJoYvZNDsEuQmMoay8XprtX8FslLh XEU0H2hfPAISNDYpH2wDgtXWzoIZGhlCSRtHdBI7245GNE1PBH94ASOkW+qxRPtLwc aHeO6+IqzLlMpnOkRmfpqOUxG8KNB3xMgHk4+ew7bwsj+Ut0noC5B2v+0bka+Om3DU iBKiYsEfvFmgg== X-CNFS-Analysis: v=2.4 cv=NqgUz+RJ c=1 sm=1 tr=0 ts=610e85b9 cx=a_exe a=Hc/BMeSBGyun2kpB8NmEvQ==:117 a=Hc/BMeSBGyun2kpB8NmEvQ==:17 a=VwQbUJbxAAAA:8 a=83yiEfbaggHBMMd4CMwA:9 a=-J8SXSngrPIHDhUm:21 a=IB70CLii7Ylv5kr1:21 a=AjGcO6oz07-iQ99wixmX:22 From: Dario Binacchi To: linux-kernel@vger.kernel.org Cc: Gianluca Falavigna , Dario Binacchi , Andrew Lunn , "David S. Miller" , Jakub Kicinski , Marc Kleine-Budde , Oliver Hartkopp , Vincent Mailhol , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v3 3/4] can: c_can: support tx ring algorithm Date: Sat, 7 Aug 2021 15:07:59 +0200 Message-Id: <20210807130800.5246-4-dariobin@libero.it> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210807130800.5246-1-dariobin@libero.it> References: <20210807130800.5246-1-dariobin@libero.it> X-CMAE-Envelope: MS4xfGmoOd6GOqyevjfeI0zB2i24sWp8gcgfOcTme321pSFLb1391FI8sMh2uwQ33GcP7ve3oVNJSCCFK4M3gta3YFF46gmfy8mjPINjb8SgQk0sYSYElZIA TUeZZw2dN2t4yilSRcoCASz1cP8wYxJdheHTh2TDubSnu1KMKvrBSjixj/xAQlh0srNHUpZq+fvScR6KjwQAFKlwSshQaoJYwy8a93WutjcdeYo2sPbgEV0V 87DlYFJcDo2CZFerCOip/5We7BHD/vePwPMkh+nQPBre0rNu3FoxEFb+8ye/JZ8mDKjJRRmD28T6Kh0UZiWhPI36l6zkOjO8mC4+LwhiACB8DVCHNmuRIIkq 9GXLpCW9SfKZl5mbqM2ZXrytcRFlDrHH79dcWSKuL7WfTT6n7xu3r0Ja0L3ooH92rv7rphRPTAyj3gbZvdpaTUM1IOX2qCaqXGY+NgMo3LPxh3BDqUxjZqws FRVHuAPNt/+We5kFVbITTHpKerkDPnn+wyi99wh++3AOueuUJeInuCnWZNy7fsxx51VuNzeuHuYyg5fUgocvbcs9VefTESy0jnyFU2zj1GEkVJysMtOff9Gj dQo= Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The algorithm is already used successfully by other CAN drivers (e.g. mcp251xfd). Its implementation was kindly suggested to me by Marc Kleine-Budde following a patch I had previously submitted. You can find every detail at https://lore.kernel.org/patchwork/patch/1422929/. The idea is that after this patch, it will be easier to patch the driver to use the message object memory as a true FIFO. Suggested-by: Marc Kleine-Budde Signed-off-by: Dario Binacchi --- (no changes since v2) Changes in v2: - Move c_can_get_tx_free() from c_can_main.c to c_can.h. drivers/net/can/c_can/c_can.h | 33 ++++++++++++++- drivers/net/can/c_can/c_can_main.c | 67 ++++++++++++++++++++++-------- 2 files changed, 82 insertions(+), 18 deletions(-) diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h index 8f23e9c83c84..9b4e54c950a6 100644 --- a/drivers/net/can/c_can/c_can.h +++ b/drivers/net/can/c_can/c_can.h @@ -176,6 +176,13 @@ struct c_can_raminit { bool needs_pulse; }; +/* c_can tx ring structure */ +struct c_can_tx_ring { + unsigned int head; + unsigned int tail; + unsigned int obj_num; +}; + /* c_can private data structure */ struct c_can_priv { struct can_priv can; /* must be the first member */ @@ -190,10 +197,10 @@ struct c_can_priv { unsigned int msg_obj_tx_first; unsigned int msg_obj_tx_last; u32 msg_obj_rx_mask; - atomic_t tx_active; atomic_t sie_pending; unsigned long tx_dir; int last_status; + struct c_can_tx_ring tx; u16 (*read_reg)(const struct c_can_priv *priv, enum reg index); void (*write_reg)(const struct c_can_priv *priv, enum reg index, u16 val); u32 (*read_reg32)(const struct c_can_priv *priv, enum reg index); @@ -219,4 +226,28 @@ int c_can_power_down(struct net_device *dev); void c_can_set_ethtool_ops(struct net_device *dev); +static inline u8 c_can_get_tx_head(const struct c_can_tx_ring *ring) +{ + return ring->head & (ring->obj_num - 1); +} + +static inline u8 c_can_get_tx_tail(const struct c_can_tx_ring *ring) +{ + return ring->tail & (ring->obj_num - 1); +} + +static inline u8 c_can_get_tx_free(const struct c_can_tx_ring *ring) +{ + u8 head = c_can_get_tx_head(ring); + u8 tail = c_can_get_tx_tail(ring); + + /* This is not a FIFO. C/D_CAN sends out the buffers + * prioritized. The lowest buffer number wins. + */ + if (head < tail) + return 0; + + return ring->obj_num - head; +} + #endif /* C_CAN_H */ diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c index fec0e3416970..80a6196a8d7a 100644 --- a/drivers/net/can/c_can/c_can_main.c +++ b/drivers/net/can/c_can/c_can_main.c @@ -427,24 +427,50 @@ static void c_can_setup_receive_object(struct net_device *dev, int iface, c_can_object_put(dev, iface, obj, IF_COMM_RCV_SETUP); } +static bool c_can_tx_busy(const struct c_can_priv *priv, + const struct c_can_tx_ring *tx_ring) +{ + if (c_can_get_tx_free(tx_ring) > 0) + return false; + + netif_stop_queue(priv->dev); + + /* Memory barrier before checking tx_free (head and tail) */ + smp_mb(); + + if (c_can_get_tx_free(tx_ring) == 0) { + netdev_dbg(priv->dev, + "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n", + tx_ring->head, tx_ring->tail, + tx_ring->head - tx_ring->tail); + return true; + } + + netif_start_queue(priv->dev); + return false; +} + static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, struct net_device *dev) { struct can_frame *frame = (struct can_frame *)skb->data; struct c_can_priv *priv = netdev_priv(dev); + struct c_can_tx_ring *tx_ring = &priv->tx; u32 idx, obj; if (can_dropped_invalid_skb(dev, skb)) return NETDEV_TX_OK; - /* This is not a FIFO. C/D_CAN sends out the buffers - * prioritized. The lowest buffer number wins. - */ - idx = fls(atomic_read(&priv->tx_active)); - obj = idx + priv->msg_obj_tx_first; - /* If this is the last buffer, stop the xmit queue */ - if (idx == priv->msg_obj_tx_num - 1) + if (c_can_tx_busy(priv, tx_ring)) + return NETDEV_TX_BUSY; + + idx = c_can_get_tx_head(tx_ring); + tx_ring->head++; + if (c_can_get_tx_free(tx_ring) == 0) netif_stop_queue(dev); + + obj = idx + priv->msg_obj_tx_first; + /* Store the message in the interface so we can call * can_put_echo_skb(). We must do this before we enable * transmit as we might race against do_tx(). @@ -453,8 +479,6 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, priv->dlc[idx] = frame->len; can_put_echo_skb(skb, dev, idx, 0); - /* Update the active bits */ - atomic_add(BIT(idx), &priv->tx_active); /* Start transmission */ c_can_object_put(dev, IF_TX, obj, IF_COMM_TX); @@ -567,6 +591,7 @@ static int c_can_software_reset(struct net_device *dev) static int c_can_chip_config(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); + struct c_can_tx_ring *tx_ring = &priv->tx; int err; err = c_can_software_reset(dev); @@ -598,7 +623,8 @@ static int c_can_chip_config(struct net_device *dev) priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED); /* Clear all internal status */ - atomic_set(&priv->tx_active, 0); + tx_ring->head = 0; + tx_ring->tail = 0; priv->tx_dir = 0; /* set bittiming params */ @@ -696,14 +722,14 @@ static int c_can_get_berr_counter(const struct net_device *dev, static void c_can_do_tx(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); + struct c_can_tx_ring *tx_ring = &priv->tx; struct net_device_stats *stats = &dev->stats; - u32 idx, obj, pkts = 0, bytes = 0, pend, clr; + u32 idx, obj, pkts = 0, bytes = 0, pend; if (priv->msg_obj_tx_last > 32) pend = priv->read_reg32(priv, C_CAN_INTPND3_REG); else pend = priv->read_reg(priv, C_CAN_INTPND2_REG); - clr = pend; while ((idx = ffs(pend))) { idx--; @@ -723,11 +749,14 @@ static void c_can_do_tx(struct net_device *dev) if (!pkts) return; - /* Clear the bits in the tx_active mask */ - atomic_sub(clr, &priv->tx_active); - - if (clr & BIT(priv->msg_obj_tx_num - 1)) - netif_wake_queue(dev); + tx_ring->tail += pkts; + if (c_can_get_tx_free(tx_ring)) { + /* Make sure that anybody stopping the queue after + * this sees the new tx_ring->tail. + */ + smp_mb(); + netif_wake_queue(priv->dev); + } stats->tx_bytes += bytes; stats->tx_packets += pkts; @@ -1206,6 +1235,10 @@ struct net_device *alloc_c_can_dev(int msg_obj_num) priv->msg_obj_tx_last = priv->msg_obj_tx_first + priv->msg_obj_tx_num - 1; + priv->tx.head = 0; + priv->tx.tail = 0; + priv->tx.obj_num = msg_obj_tx_num; + netif_napi_add(dev, &priv->napi, c_can_poll, priv->msg_obj_rx_num); priv->dev = dev; From patchwork Sat Aug 7 13:08:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dario Binacchi X-Patchwork-Id: 493584 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6B80C4338F for ; Sat, 7 Aug 2021 13:09:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F85160C3F for ; Sat, 7 Aug 2021 13:09:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232350AbhHGNJa (ORCPT ); Sat, 7 Aug 2021 09:09:30 -0400 Received: from smtp-32.italiaonline.it ([213.209.10.32]:57646 "EHLO libero.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S232315AbhHGNJ1 (ORCPT ); Sat, 7 Aug 2021 09:09:27 -0400 Received: from passgat-Modern-14-A10M.homenet.telecomitalia.it ([82.60.87.158]) by smtp-32.iol.local with ESMTPA id CM3WmQm3XPvRTCM3dmIfZb; Sat, 07 Aug 2021 15:08:09 +0200 x-libjamoibt: 1601 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=libero.it; s=s2021; t=1628341689; bh=AckADGcKabU1CkSpV4t7qzvQ6zrVoNpS9rhgk52TYv0=; h=From; b=smRCHIBK8S6QqS7tkru9LBe/cQwDrZcfQFF6q0cP2i7unpVPIscnkqubkglJCAj+v uayEpMUnjl7ROMw+dIdClFEQRo9nQHmNivzpSJ8piPV7A+m7+mNBTolNcRgcNRKJAm ThjDkiMELzmYlcclMoyc2jCI//UsLps7yOTymwwAThH3mmfcHZjuP1mnebx9lbQimi kb9A48CtSve/IYVpAeKlnUgwohS/ERbKRB8QToy906rTxcNj7IYCxcQRRKnGc8ZFmj onpSCwyDIensMPsXKreJTDbMmnw61/2EJTVoCG/i9QE/aZ9/u41AiLmRKbgPAZyF8k LBUUJiV/K6s0Q== X-CNFS-Analysis: v=2.4 cv=NqgUz+RJ c=1 sm=1 tr=0 ts=610e85b9 cx=a_exe a=Hc/BMeSBGyun2kpB8NmEvQ==:117 a=Hc/BMeSBGyun2kpB8NmEvQ==:17 a=ZFJuXQVxYH-b9Oyd0qwA:9 From: Dario Binacchi To: linux-kernel@vger.kernel.org Cc: Gianluca Falavigna , Dario Binacchi , Andrew Lunn , "David S. Miller" , Jakub Kicinski , Marc Kleine-Budde , Oliver Hartkopp , Vincent Mailhol , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v3 4/4] can: c_can: cache frames to operate as a true FIFO Date: Sat, 7 Aug 2021 15:08:00 +0200 Message-Id: <20210807130800.5246-5-dariobin@libero.it> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210807130800.5246-1-dariobin@libero.it> References: <20210807130800.5246-1-dariobin@libero.it> X-CMAE-Envelope: MS4xfGmoOd6GOqyevjfeI0zB2i24sWp8gcgfOcTme321pSFLb1391FI8sMh2uwQ33GcP7ve3oVNJSCCFK4M3gta3YFF46gmfy8mjPINjb8SgQk0sYSYElZIA TUeZZw2dN2t4yilSRcoCASz1cP8wYxJdheHTh2TDubSnu1KMKvrBSjixj/xAQlh0srNHUpZq+fvScR6KjwQAFKlwSshQaoJYwy8a93WutjcdeYo2sPbgEV0V 87DlYFJcDo2CZFerCOip/5We7BHD/vePwPMkh+nQPBre0rNu3FoxEFb+8ye/JZ8mDKjJRRmD28T6Kh0UZiWhPI36l6zkOjO8mC4+LwhiACB8DVCHNmuRIIkq 9GXLpCW9SfKZl5mbqM2ZXrytcRFlDrHH79dcWSKuL7WfTT6n7xu3r0Ja0L3ooH92rv7rphRPTAyj3gbZvdpaTUM1IOX2qCaqXGY+NgMo3LPxh3BDqUxjZqws FRVHuAPNt/+We5kFVbITTHpKerkDPnn+wyi99wh++3AOueuUJeInuCnWZNy7fsxx51VuNzeuHuYyg5fUgocvbcs9VefTESy0jnyFU2zj1GEkVJysMtOff9Gj dQo= Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org As reported by a comment in the c_can_start_xmit() this was not a FIFO. C/D_CAN controller sends out the buffers prioritized so that the lowest buffer number wins. What did c_can_start_xmit() do if head was less tail in the tx ring ? It waited until all the frames queued in the FIFO was actually transmitted by the controller before accepting a new CAN frame to transmit, even if the FIFO was not full, to ensure that the messages were transmitted in the order in which they were loaded. By storing the frames in the FIFO without requiring its transmission, we will be able to use the full size of the FIFO even in cases such as the one described above. The transmission interrupt will trigger their transmission only when all the messages previously loaded but stored in less priority positions of the buffers have been transmitted. Suggested-by: Gianluca Falavigna Signed-off-by: Dario Binacchi --- Changes in v3: - Remove the transmission spin_lock. - Use IF_RX in c_can_do_tx(). drivers/net/can/c_can/c_can.h | 11 +---------- drivers/net/can/c_can/c_can_main.c | 23 ++++++++++++++++++----- 2 files changed, 19 insertions(+), 15 deletions(-) diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h index 9b4e54c950a6..08b6efa7a1a7 100644 --- a/drivers/net/can/c_can/c_can.h +++ b/drivers/net/can/c_can/c_can.h @@ -238,16 +238,7 @@ static inline u8 c_can_get_tx_tail(const struct c_can_tx_ring *ring) static inline u8 c_can_get_tx_free(const struct c_can_tx_ring *ring) { - u8 head = c_can_get_tx_head(ring); - u8 tail = c_can_get_tx_tail(ring); - - /* This is not a FIFO. C/D_CAN sends out the buffers - * prioritized. The lowest buffer number wins. - */ - if (head < tail) - return 0; - - return ring->obj_num - head; + return ring->obj_num - (ring->head - ring->tail); } #endif /* C_CAN_H */ diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c index 80a6196a8d7a..e26b097b11ff 100644 --- a/drivers/net/can/c_can/c_can_main.c +++ b/drivers/net/can/c_can/c_can_main.c @@ -456,7 +456,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, struct can_frame *frame = (struct can_frame *)skb->data; struct c_can_priv *priv = netdev_priv(dev); struct c_can_tx_ring *tx_ring = &priv->tx; - u32 idx, obj; + u32 idx, obj, cmd = IF_COMM_TX; if (can_dropped_invalid_skb(dev, skb)) return NETDEV_TX_OK; @@ -469,7 +469,8 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, if (c_can_get_tx_free(tx_ring) == 0) netif_stop_queue(dev); - obj = idx + priv->msg_obj_tx_first; + if (idx < c_can_get_tx_tail(tx_ring)) + cmd &= ~IF_COMM_TXRQST; /* Cache the message */ /* Store the message in the interface so we can call * can_put_echo_skb(). We must do this before we enable @@ -478,9 +479,8 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, c_can_setup_tx_object(dev, IF_TX, frame, idx); priv->dlc[idx] = frame->len; can_put_echo_skb(skb, dev, idx, 0); - - /* Start transmission */ - c_can_object_put(dev, IF_TX, obj, IF_COMM_TX); + obj = idx + priv->msg_obj_tx_first; + c_can_object_put(dev, IF_TX, obj, cmd); return NETDEV_TX_OK; } @@ -725,6 +725,7 @@ static void c_can_do_tx(struct net_device *dev) struct c_can_tx_ring *tx_ring = &priv->tx; struct net_device_stats *stats = &dev->stats; u32 idx, obj, pkts = 0, bytes = 0, pend; + u8 tail; if (priv->msg_obj_tx_last > 32) pend = priv->read_reg32(priv, C_CAN_INTPND3_REG); @@ -761,6 +762,18 @@ static void c_can_do_tx(struct net_device *dev) stats->tx_bytes += bytes; stats->tx_packets += pkts; can_led_event(dev, CAN_LED_EVENT_TX); + + tail = c_can_get_tx_tail(tx_ring); + + if (tail == 0) { + u8 head = c_can_get_tx_head(tx_ring); + + /* Start transmission for all cached messages */ + for (idx = tail; idx < head; idx++) { + obj = idx + priv->msg_obj_tx_first; + c_can_object_put(dev, IF_RX, obj, IF_COMM_TXRQST); + } + } } /* If we have a gap in the pending bits, that means we either