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[80.116.90.174]) by smtp.gmail.com with ESMTPSA id b20-20020a0564021f1400b0042e15364d14sm9916952edb.8.2022.06.28.09.31.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jun 2022 09:31:56 -0700 (PDT) From: Dario Binacchi To: linux-kernel@vger.kernel.org Cc: michael@amarulasolutions.com, Amarula patchwork , Oliver Hartkopp , Dario Binacchi , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Marc Kleine-Budde , Paolo Abeni , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v5 06/12] can: slcan: allow to send commands to the adapter Date: Tue, 28 Jun 2022 18:31:30 +0200 Message-Id: <20220628163137.413025-7-dario.binacchi@amarulasolutions.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220628163137.413025-1-dario.binacchi@amarulasolutions.com> References: <20220628163137.413025-1-dario.binacchi@amarulasolutions.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a preparation patch for the upcoming support to change the bitrate via ip tool, reset the adapter error states via the ethtool API and, more generally, send commands to the adapter. Since the close command (i. e. "C\r") will be sent in the ndo_stop() where netif_running() returns false, a new flag bit (i. e. SLF_XCMD) for serial transmission has to be added. Signed-off-by: Dario Binacchi --- (no changes since v4) Changes in v4: - Replace `sl->tty == NULL' with `!sl->tty'. Changes in v3: - Update the commit description. drivers/net/can/slcan.c | 46 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 45 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c index bf84698f1a81..dfccf8d6c9a5 100644 --- a/drivers/net/can/slcan.c +++ b/drivers/net/can/slcan.c @@ -97,6 +97,9 @@ struct slcan { unsigned long flags; /* Flag values/ mode etc */ #define SLF_INUSE 0 /* Channel in use */ #define SLF_ERROR 1 /* Parity, etc. error */ +#define SLF_XCMD 2 /* Command transmission */ + wait_queue_head_t xcmd_wait; /* Wait queue for commands */ + /* transmission */ }; static struct net_device **slcan_devs; @@ -314,12 +317,22 @@ static void slcan_transmit(struct work_struct *work) spin_lock_bh(&sl->lock); /* First make sure we're connected. */ - if (!sl->tty || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) { + if (!sl->tty || sl->magic != SLCAN_MAGIC || + (unlikely(!netif_running(sl->dev)) && + likely(!test_bit(SLF_XCMD, &sl->flags)))) { spin_unlock_bh(&sl->lock); return; } if (sl->xleft <= 0) { + if (unlikely(test_bit(SLF_XCMD, &sl->flags))) { + clear_bit(SLF_XCMD, &sl->flags); + clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); + spin_unlock_bh(&sl->lock); + wake_up(&sl->xcmd_wait); + return; + } + /* Now serial buffer is almost free & we can start * transmission of another packet */ sl->dev->stats.tx_packets++; @@ -383,6 +396,36 @@ static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev) * Routines looking at netdevice side. ******************************************/ +static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd) +{ + int ret, actual, n; + + spin_lock(&sl->lock); + if (!sl->tty) { + spin_unlock(&sl->lock); + return -ENODEV; + } + + n = snprintf(sl->xbuff, sizeof(sl->xbuff), "%s", cmd); + set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); + actual = sl->tty->ops->write(sl->tty, sl->xbuff, n); + sl->xleft = n - actual; + sl->xhead = sl->xbuff + actual; + set_bit(SLF_XCMD, &sl->flags); + spin_unlock(&sl->lock); + ret = wait_event_interruptible_timeout(sl->xcmd_wait, + !test_bit(SLF_XCMD, &sl->flags), + HZ); + clear_bit(SLF_XCMD, &sl->flags); + if (ret == -ERESTARTSYS) + return ret; + + if (ret == 0) + return -ETIMEDOUT; + + return 0; +} + /* Netdevice UP -> DOWN routine */ static int slc_close(struct net_device *dev) { @@ -540,6 +583,7 @@ static struct slcan *slc_alloc(void) sl->dev = dev; spin_lock_init(&sl->lock); INIT_WORK(&sl->tx_work, slcan_transmit); + init_waitqueue_head(&sl->xcmd_wait); slcan_devs[i] = dev; return sl; -- 2.32.0