From mboxrd@z Thu Jan 1 00:00:00 1970 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 19484C43381 for ; Fri, 8 Mar 2019 14:41:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8D4B2085A for ; Fri, 8 Mar 2019 14:41:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726865AbfCHOlo (ORCPT ); Fri, 8 Mar 2019 09:41:44 -0500 Received: from mailproxy03.manitu.net ([217.11.48.67]:39942 "EHLO mailproxy03.manitu.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726491AbfCHOln (ORCPT ); Fri, 8 Mar 2019 09:41:43 -0500 Received: from [10.0.30.7] (dslb-188-099-219-116.188.099.pools.vodafone-ip.de [188.99.219.116]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: wg@grandegger.com) by mailproxy03.manitu.net (Postfix) with ESMTPSA id 9954CD4003D; Fri, 8 Mar 2019 15:45:29 +0100 (CET) Subject: Re: [PATCH v7 1/4] can: m_can: Create a m_can platform framework From: Wolfgang Grandegger To: Dan Murphy , mkl@pengutronix.de, davem@davemloft.net Cc: linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190305155220.14037-1-dmurphy@ti.com> <5065d6ba-f195-a695-77b1-b837cac1a199@grandegger.com> Openpgp: preference=signencrypt Autocrypt: addr=wg@grandegger.com; prefer-encrypt=mutual; keydata= mQINBFtEb5MBEAC5aRjs5jLwjbOaEE6rczZSqck7B3iGK8ldrV8HGSjxb1MAf4VbvDWrzXfA phEgX3e54AnYhnKcf6BA3J9TlSDdUAW7r/ijOFl+TehMz7holgjhlDK41acJ/klwXJotIqby bWqFgFw6o7b8hfbVzPi8Pz/+WOIKaDOb1Keb989mn253RF1yFakgvoQfCyAeVcnO5kcByW17 zbTEHsSduYi0Zir26Oedb2Vtas4SovrEXVh4e2dRdbEbHlI8po3Ih117CuGIPAe2RSfZKY88 8c9m+WsJKtrIDIMY+f5kcHG5mib++u1oTg7wjfFgTr925g2WjzT63YRibW8Vazot9yXquMo2 HYQStmnN9MuAkL/jslnxhGKNwTzpXv6FD2g/9hcLfSjaaCwGzj2j2ucJglJnO1n+ibVB14l2 JLVe+IKJaE1gvm2v9HPsE+o1P4O8I9iCiAbQ6BGUszHADOg7r8CeTQ+AOCypfEZ5l1Hwa3gw V+TtqyCU70U9LA0AKaDZ02vf0hFRWeXV/ErFq878GOXbbVMZu8G5aO0EcCBC75/KQnyi0WEl KVIcyTyxKel/Ext7vUFIkiA16JNWRpS85YDfe9CoEZcZK+nUU268j6Bp5a7MYaF/dZaLT+Du hLA82ry8IkPQvyV5yV+B0PwDM/w7de8zIzMy9YBXU8KGGDmgYQARAQABtCdXb2xmZ2FuZyBH cmFuZGVnZ2VyIDx3Z0BncmFuZGVnZ2VyLmNvbT6JAj8EEwECACkFAltEb5MCGyMFCQlmAYAH CwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAAKCRDwuz7LbZzIUhvED/4vTUqS0c/V5a4hc5Md u/8qkF7qg011tM0lXrZZxMQ8NrjdFuDhUefZ1q59QbLFU9da9D/CRVJUSx6BnY9jkR6lIm9l OGqS9ZlzubGXJCZhv1ONWPwY/i1RXTtauhRy+nkcyJk2Bzs5PWq1i4hWXpX//GfGUbCt+2bX 2+9bmHSPFtZ/MpIigS1E8RehIzlzqC/NCJspY8H0HKtLR6kpanRBYCuYSlBom/1LEP2MmXhh 9LgjQINp+jZJwnBj5L5JaUn/sg2WO+IiN6IphzyS2TvrlRhkhPJv5EOf0QmYzDgz5eU/h35x aCclLSJ0Go83GO0bXFGCzN86VreRgLRGTa7/x9VW05LiBdlsuLpG23IHM5f6p0WpYgE+jdri TrMued/DquQEcw/xNXpa3n9zTghLcWgcqGIdK3AE3yPjQBR3N6WoT4VOXnZjg6pyNHQ3W4qj LQgzJ3Tq2gPMhRLFcLXyk6V3rQ0ffn4LCXkFYVIBGAN8hHMOFeV6NESkUcEil6V4oOsLLGuJ XreFjAl1Cz3vIaVgzZEfub1z60DDM71lIr+UvWXLeMyKiSMWiJBPL3LUoUWmzpafaTJakDWm CEXa871Jlw7sy99MGVhiVG74JHjtPE6ontM1dKCP1+yT53TeGp1o/3Hj3sUielfDr5nV/kT6 p5zmgQN/1bJgV/3sKrkCDQRbRG+TARAA37mw9iosCWO5OtCrbvgJJwzOR3XrijVKi9KTNzDO NT2iy7teKP4+C+9why6iZhoJbBrTo56mbmI2nvfyOthxCa8nT14js8q0EgSMiyxXVeRvzEIQ sYcG4zgbGjwJ94Vrr5tMCFn5B6cYKJffTGmfY0D3b2V4GqaCGxVs3lWcQJeKl/raL8lp4YWz AI0jVx104W7rUbCTDvcSVfPqwM+9A6xaP4b1jwyYwGHgOTq6SeimRrGgM+UNtWqMU3+vUelG 8gKDyfIIo4IrceeHss5OuRREQZq5vNuzkeIY6faYWv65KT+IQ6EyC9UEGkMdcStfEsZO53Qq buA7Kha6lVViDM3vjGS+fnNq/od53dosWeWQ4O8M7Z6nxgp+EOPuJf041eKmIrcaRiXb+027 x4D0Kwv/xVsFa6cC2lkITWahENFIXwKOZ3imr2ZCtVF61qnm/GQ5P27JQKXMbPOM6wm0EjJ1 9t2EkSpgVHI0Cd0ldxD4eaGNwpeHJ5WGGzZrOE7PCcRziJX0qO/FpLjTQ6scf+bPACgduY71 AwXyA24mg7F2vK+Vth+Yp7MlgwYBMUy6D140jrkWrcRxKYfW1BgcKpbG/dh5DhUAvoOzFD7i zHrGK5FhzqJDBwKk7n9jGohf/MJWs2UKai/u4ogZBhhD5JPR8GG6VzO4snWisFLFuAEAEQEA AYkCJQQYAQIADwUCW0RvkwIbDAUJCWYBgAAKCRDwuz7LbZzIUkA3D/wJOvcQ7rTeoRiamOIB kD4n2Jsv8Vti/XfM0DTmhfnWL4y96VzSzNfl+EHAwXE4161qnXxTHnFK1hq7QklNdDiGW3iH nKZUyHUTnlUlCocv8jWtlqrpH0XVtF12JET65mE14Hga6BQ4ECXwU2GcP3202A55EzMj31b/ 59GD3CDIJy7bjQi+pIRuA9ZQRsFas7Od7AWO/nFns2wJ6AJkjXdCUCZ4iOuf82gLK9olDSmd H73Epc6l3jca62L2Lzei405LQSsfOZ06uH2aGPUJX4odUlEF6arm2j+9Q8Vyi4CJ316f2kAa sl7LhAwZtaj8hjl/PUWfd5w47dUBDUZjIRYcdM2TTU3Spgvg3zqXUzur5+r0jkUl2naeiSB1 vwjfIwnPqZOVr9FAXuLbAdUyCCC0ohGLrq5Nsc1A02rxpQHRxTSm2FOdn2jYvuD7JUgkhmUh /TXb8aL6A4hfX7oV4tGq7nSmDOCmgWRmAHAGp85fVq2iylCxZ1kKi8EYCSa28eQzetukFbAx JwmcrUSaCOK+jpHlNY0PkghSIzAE/7Se+c37unJ39xJLkrgehLYmUF7cBeNWhfchu4fAJosM 5mXohGkBKcd5YYmF13imYtAG5/VSmBm/0CFNGFO49MVTNGXGBznrPrWwtPZNwjJdi7JrvEbm 8QEfHnPzgykCs2DOOQ== Message-ID: Date: Fri, 8 Mar 2019 15:41:39 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Dan, thinking more about it... Am 08.03.19 um 14:29 schrieb Wolfgang Grandegger: > Hello Dan, > > Am 08.03.19 um 13:44 schrieb Dan Murphy: >> Wolfgang >> >> On 3/8/19 4:10 AM, Wolfgang Grandegger wrote: >>> Hallo Dan, >>> >>> Am 05.03.19 um 16:52 schrieb Dan Murphy: >>>> Create a m_can platform framework that peripherial >>>> devices can register to and use common code and register sets. >>>> The peripherial devices may provide read/write and configuration >>>> support of the IP. >>>> >>>> Signed-off-by: Dan Murphy >>>> --- >>>> >>>> >>>> v7 - Fixed remaining new checkpatch issues, removed CSR setting, fixed tx hard >>>> start function to return tx_busy, and renamed device callbacks - https://lore.kernel.org/patchwork/patch/1047220/ >>>> >>>> v6 - Squashed platform patch to this patch for bissectablity, fixed coding style >>>> issues, updated Kconfig help, placed mcan reg offsets back into c file, renamed >>>> priv->skb to priv->tx_skb and cleared perp interrupts at ISR start - >>>> Patch 1 comments - https://lore.kernel.org/patchwork/patch/1042446/ >>>> Patch 2 comments - https://lore.kernel.org/patchwork/patch/1042442/ >>>> >>>> drivers/net/can/m_can/Kconfig | 13 +- >>>> drivers/net/can/m_can/Makefile | 1 + >>>> drivers/net/can/m_can/m_can.c | 700 +++++++++++++------------ >>>> drivers/net/can/m_can/m_can.h | 110 ++++ >>>> drivers/net/can/m_can/m_can_platform.c | 202 +++++++ >>>> 5 files changed, 682 insertions(+), 344 deletions(-) >>>> create mode 100644 drivers/net/can/m_can/m_can.h >>>> create mode 100644 drivers/net/can/m_can/m_can_platform.c >>>> >>>> diff --git a/drivers/net/can/m_can/Kconfig b/drivers/net/can/m_can/Kconfig >>>> index 04f20dd39007..f7119fd72df4 100644 >>>> --- a/drivers/net/can/m_can/Kconfig >>>> +++ b/drivers/net/can/m_can/Kconfig >>>> @@ -1,5 +1,14 @@ >>>> config CAN_M_CAN >>>> + tristate "Bosch M_CAN support" >>>> + ---help--- >>>> + Say Y here if you want support for Bosch M_CAN controller framework. >>>> + This is common support for devices that embed the Bosch M_CAN IP. >>>> + >>>> +config CAN_M_CAN_PLATFORM >>>> + tristate "Bosch M_CAN support for io-mapped devices" >>>> depends on HAS_IOMEM >>>> - tristate "Bosch M_CAN devices" >>>> + depends on CAN_M_CAN >>>> ---help--- >>>> - Say Y here if you want to support for Bosch M_CAN controller. >>>> + Say Y here if you want support for IO Mapped Bosch M_CAN controller. >>>> + This support is for devices that have the Bosch M_CAN controller >>>> + IP embedded into the device and the IP is IO Mapped to the processor. >>>> diff --git a/drivers/net/can/m_can/Makefile b/drivers/net/can/m_can/Makefile >>>> index 8bbd7f24f5be..057bbcdb3c74 100644 >>>> --- a/drivers/net/can/m_can/Makefile >>>> +++ b/drivers/net/can/m_can/Makefile >>>> @@ -3,3 +3,4 @@ >>>> # >>>> >>>> obj-$(CONFIG_CAN_M_CAN) += m_can.o >>>> +obj-$(CONFIG_CAN_M_CAN_PLATFORM) += m_can_platform.o >>>> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c >>>> index 9b449400376b..a60278d94126 100644 >>>> --- a/drivers/net/can/m_can/m_can.c >>>> +++ b/drivers/net/can/m_can/m_can.c >>> >>> ... snip... >>> >>>> +static netdev_tx_t m_can_start_xmit(struct sk_buff *skb, >>>> + struct net_device *dev) >>>> +{ >>>> + struct m_can_priv *priv = netdev_priv(dev); >>>> + >>>> + if (can_dropped_invalid_skb(dev, skb)) >>>> + return NETDEV_TX_OK; >>>> + >>>> + if (priv->is_peripherial) { >>>> + if (priv->tx_skb) { >>>> + netdev_err(dev, "hard_xmit called while tx busy\n"); >>>> + return NETDEV_TX_BUSY; >>>> + } >>> >>> The problem with that approach is, that the upper layer will try to >>> resubmit the current "skb" but not the previous "tx_skb". And the >>> previous "tx_skb" has not been freed yet. I would just drop and free the >>> skb and return NETDEV_TX_OK in m_can_tx_handler() for peripheral devices >>> (like can_dropped_invalid_skb() does). >>> >> >> OK. >> >> So would this also be a bug in the hi3110 and mcp251x drivers (line 521) as well because besides checking tx_length >> this is how these drivers are written. > > This is different. When entering the "start_xmit" routine, the previous > TX is still in progress. It will (hopefully) complete soon. Therefore > returning NETDEV_TX_BUSY is OK. The "start_xmit" routine will be > recalled soon with the same "skb". That scenario should/could also not > happen. In principle, this also applies to the m_can peripheral devices. If tx_skb is not NULL, the TX is still in progress and returning NETDEV_TX_BUSY is just fine. > > In contrast, in "m_can_tx_handler()", the skb could not be handled > because the FIFO is full. The "start_xmit" routine for peripheral > devices for that skb already returned NETDEV_TX_OK. Therefore the only > meaningful action is to drop the skb. Also this error should not happen > and if, something is going really wrong. Therefore I think, a > WARN_ONCE() would be even more appropriate. But that should be a > separate patch. But that's a different issue/error. The tx_skb cannot be processed in "m_can_tx_handler()". Either we drop it or we re-queue it (retry later). >> >> In addition in the peripheral context the work queue does not report up to the upper layer the status. >> Again the hi3110 and mcp251x drivers are written this way. >> >> The only issue I see here is that the dropped and invalid check needs to come after the tx_skb check. > > See above. Wolfgang.