From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pidgin.makrotopia.org (pidgin.makrotopia.org [185.142.180.65]) (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 38286222565; Sun, 9 Aug 2026 17:08:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.142.180.65 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786295314; cv=none; b=HKcTJWlxMha9DC8FERJDa1m9BrsK4uKLrNAuieqyxYhD+qWXKIgfgAOxFKvvNN2I1uEJ+/LdVgns32E3XrSE0810+7mfz79/gr6uRYNYG/3apUrcdrAQSH4K2f3EMrjvu7Io/4MBAvFnegWKKB12nLuvcfXnhIeD7dmIJs485kc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786295314; c=relaxed/simple; bh=uxzAERrTO3wZzK8q6Um1TXPssw4lWXGMtgfjX/DNVFA=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dsWwHg64X/lKRlfU4jIpOwH5Y4HjrobkZR2M+yiF6GgjhH6wKG3DSUeDvaVdXxKdmpQW4NNIm6P1k7TjYPbBfkPMr5xAbPC4+BkuFtwpz/puG2FrMu5PuPm36jpznQS/RqvHfHCaBpjbUtI7x9x3mohzrTB2v46A1LZMVIiE2OI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=makrotopia.org; spf=pass smtp.mailfrom=makrotopia.org; arc=none smtp.client-ip=185.142.180.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=makrotopia.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=makrotopia.org Received: from local by pidgin.makrotopia.org with esmtpsa (TLS1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.99) (envelope-from ) id 1wt70Z-000000000Qn-0tFm; Sun, 09 Aug 2026 17:08:23 +0000 Date: Sun, 9 Aug 2026 18:08:14 +0100 From: Daniel Golle To: Jiri Pirko , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jonathan Corbet , Shuah Khan , Daniel Golle , Andrew Lunn , Vladimir Oltean , netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v10 4/5] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode Message-ID: <513eb8147a2c74762bf700b2859bb39469aaa707.1786294649.git.daniel@makrotopia.org> References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: A broken or interrupted firmware image, or the sticky rescue bit, keeps the switch in its MCUboot bootloader, which exposes only the clause-22 SMDIO download interface. The clause-45 MMD API never comes up, so probe would fail with -ETIMEDOUT and the only way back would be the switch's UART console, or a power cycle or out-of-band reset (not currently implemented). Probe for the loader over SB PDI at setup, before any clause-45 access, since the C45 API floods the log with CRC errors when no firmware answers. A scratch write to two mailbox registers first establishes that a switch is there at all. It reaches a running firmware as well, but lands in registers that firmware does not read, so it is inert there. The status register the loader publishes then tells the cases apart without touching C45: a running firmware, which answers with its own non-zero status word (0x0003 on the firmware tested), so probe continues normally; a loader idle in its console loop, confirmed live by a register-read challenge; a loader wedged mid-download, the one case that publishes zero; the flashless download loop, which this driver cannot drive; and a switch whose scratch write does not latch -- absent, unpowered, misdescribed in the device tree (wrong address or bus, or a reset GPIO with inverted polarity), or with its SB PDI window somewhere other than the OTP reset offsets assumed here. The first three enter rescue mode or normal operation, the last two fail probe cleanly with -EOPNOTSUPP and -ENODEV instead of a CRC-error storm. A loader that publishes the ready magic but never services the register-read challenge fails probe too, with -ENXIO. The challenge is what tells the loader apart from a firmware whose status word happens to read the same value, and offering to flash a healthy firmware would be worse than refusing to bind, so a mailbox that does not answer is treated as unusable rather than as a flash target. Every loader tested services it. In rescue mode the switch registers without user interfaces so devlink stays available: user ports fail port_setup with -ENODEV (the DSA core re-registers them as unused) while shared and CPU ports succeed, and the CPU port works on its fixed link with mac_select_pcs returning no PCS. Firmware API commands fail fast with -ENODEV and the port and STP callbacks become no-ops. An interrupted download can leave the loader wedged mid-payload. A background work item off the devlink flash path drains it back to a clean ready state by feeding the outstanding byte count one byte at a time, which takes tens of minutes for a large image and is logged as it progresses; until then devlink dev info reports no version and devlink dev flash returns -EBUSY, and -EIO once a drain has failed for good. Reaching the end of the count is all the drain does: the loader then verifies the corrupt image and returns to its console loop on its own, so the drain reprobes and lets the probe-time detection re-classify the switch -- a valid image that a last-moment interruption left bootable comes up as running firmware, with no second-guessing in the drain path. The reprobe the drain queues owns itself and cannot be cancelled from teardown, so, like the post-flash reprobe, it checks whether the device is still bound before touching it: a drain finishing after the driver is gone does nothing. Should that hand-off fail to be set up at all, recovery stops with an error, since the loader would otherwise sit at a clean ready state that nothing reclassifies while devlink keeps promising that a retry will work. The CHIP ID registers need a running firmware, so no asic.id/asic.rev is reported in rescue mode. Once the loader is ready, devlink dev info reports the null firmware version "0.0.0" as both running and stored: $ devlink dev info mdio_bus/mdio-bus:10 mdio_bus/mdio-bus:10: driver mxl862xx versions: running: fw 0.0.0 stored: fw 0.0.0 An operational switch never reports 0.0.0 (a released firmware's major is non-zero), so version-comparing tools like fwupd offer every release as an upgrade, recovering the switch through the regular flash flow, matched on the driver name. The flash skips the FW_UPDATE command since MCUboot is already waiting. A successful flash reboots the switch into the new firmware and the reprobe then brings the driver up against it normally; after a failed one the switch is still in MCUboot, rescue mode is detected again, and the user can retry. Signed-off-by: Daniel Golle --- v10: - share the SB PDI timeouts with the flash path: one constant for the verify wait (15 s) and one for a single 1-byte mailbox step (2 s), the latter also replacing the separate detection timeout. The last-slice flush gets the sum of the write and verify budgets, since it cannot see the boundary between programming and verifying (found by Sashiko AI review) - report a reprobe hand-off that cannot be set up after a successful drain, instead of leaving devlink answering "retry shortly" for good for a loader sitting at a clean READY (found by Sashiko AI review) - drop heal_lock and mxl862xx_stop_work() with it: making the flag test and the queueing atomic was never the guarantee its comment claimed, and the reprobe now decides for itself whether it may still run (found by Sashiko AI review) - return -ENXIO rather than a propagated -ETIMEDOUT when the loader never re-arms READY for the register-read challenge, and correct the documented return sets of mxl862xx_rescue_mode_detect() and mxl862xx_rescue_drain_finish() (found by Sashiko AI review) - explain why STAT == 0 during a drain is unambiguous: by the r_remain == 0 rule the loader cannot be both inside the receive loop asking for a chunk and publishing a verdict (found by Sashiko AI review) - commit message: a running firmware is not "left untouched", the presence probe writes two mailbox scratch registers which are inert to it; an SB PDI window away from the OTP reset offsets also yields -ENODEV; and describe the -ENXIO outcome for a READY loader that never services the challenge (found by Sashiko AI review) v9: no changes v8: - never send END from the drain: the loader keeps the host's byte count in its status register while it programs a chunk, so a lingering count cannot be told from the "image rejected" verdict, and END written into the receive loop is consumed as a 15555-byte count and underflows the receive counter. Wait for the loader to ask for the next chunk or to return to its console loop instead, since it finalises on its own (found by Sashiko AI review) - initialise the SerDes state before the rescue-mode early return, so the window between a successful rescue-mode flash clearing rescue_mode and the reprobe cannot hand phylink a PCS with no ops and an uninitialised mutex (found by Sashiko AI review) - do not fail probe when the 1-byte slice-advance leaves the wedged loader somewhere other than asking for the next chunk: a download interrupted with exactly one byte outstanding completes on that byte, after which the loader verifies and returns to its console loop (found by Sashiko AI review) - report a failed drain and refuse further flashes with -EIO and an extack asking for a power cycle, instead of leaving devlink to answer "retry shortly" forever for a switch that never becomes ready (found by Sashiko AI review) - reset the mailbox before the presence probe: a download interrupted with the write latch armed made the scratch write land in switch memory instead, so detection returned -ENODEV for the very state it exists to recover (found by Sashiko AI review) - tell an SMDIO bus error apart from a loader failing the register-read challenge, and check the reset issued after it (found by Sashiko AI review) - reject DSA links before the rescue-mode shortcut, so an unsupported cascade topology fails probe in rescue mode too (found by Sashiko AI review) - serialise the self-heal's reprobe hand-off against teardown with a mutex (found by Sashiko AI review) - log the drain's progress, name its timeouts, and describe its real duration (found by Sashiko AI review) - WRITE_ONCE() the rescue_ready stores, document what orders rescue_mode, and correct the detection kernel-doc and the note on the OTP-configurable SB PDI register offsets (found by Sashiko AI review) v7: - queue the reprobe as a delayed work item from the background self-heal, following the previous patch's move off the reprobe kthread - report the rescue-mode firmware version under DEVLINK_INFO_VERSION_GENERIC_FW too - drop two redundant rescue-recovery log lines; the setup message ("switch in MCUboot with an interrupted download, recovering in background") already says it - return distinct errno from rescue_mode_detect() so an absent switch (-ENODEV), one strapped into flashless-download mode (-EOPNOTSUPP) and one that answers SB PDI READY but fails the register-read challenge, or wedges without draining (-ENXIO), are no longer all reported as -ENODEV v6: - after the background drain finalises the interrupted transfer, reprobe and let the probe-time detection re-classify the switch, so a valid image a last-moment interruption left bootable is picked up as running firmware; rescue_drain() no longer inspects or reports the outcome (its stale kernel-doc claiming a "return 1" case is gone) - poll the drain status register with read_poll_timeout() as well, which evaluates the condition once more after the deadline, matching the poll fix in the previous patch - treat the flashless-download loop (STAT 0xc33c) as an unsupported configuration and fail probe with -ENODEV, rather than advertising it as flashable when the console flash path cannot drive it v5: - detect the switch state from the value MCUboot publishes in the SB PDI STAT register (loader ready, wedged download, or running firmware), confirming a live console loader with a register-read challenge, instead of trusting a bare SMDIO scratch write - fail probe with -ENODEV over SB PDI when the switch does not respond at all -- absent, unpowered, or misdescribed in the device tree -- instead of letting the clause-45 API flood the log with CRC errors - drain a wedged interrupted download back to a clean ready state from a background work item so the multi-minute recovery never holds the devlink instance lock, and refuse devlink dev info and flash until it is ready - report the null firmware version as the stored version too, matching the running/stored reporting of the previous patch - do not report asic.id/asic.rev in rescue mode as the CHIP ID registers are unreadable without firmware; recovery tools match on the driver name and the "0.0.0" version instead (follows the numeric asic.id change in the previous patch) - move the devlink documentation into its own patch v4: - log a distinct diagnostic when rescue mode detection fails on an SMDIO bus error instead of silently treating it as "not in rescue mode" - clear the rescue_mode flag under the MDIO bus lock, following the flag write locking in the previous patch v3: - report the canonical null version "0.0.0" instead of "mcuboot-rescue" so that version-comparing update tools like fwupd offer any available release as an upgrade for recovery - check the rescue_mode flag under the MDIO bus lock, following the block_host/skip_teardown change in the previous patch v2: new patch, allowing recovery from a failed or interrupted update without having to use a special recovery OS image (Andrew Lunn) drivers/net/dsa/mxl862xx/mxl862xx-fw.c | 463 +++++++++++++++++++- drivers/net/dsa/mxl862xx/mxl862xx-fw.h | 3 + drivers/net/dsa/mxl862xx/mxl862xx-host.c | 8 + drivers/net/dsa/mxl862xx/mxl862xx-phylink.c | 2 + drivers/net/dsa/mxl862xx/mxl862xx.c | 100 ++++- drivers/net/dsa/mxl862xx/mxl862xx.h | 20 + 6 files changed, 566 insertions(+), 30 deletions(-) diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-fw.c b/drivers/net/dsa/mxl862xx/mxl862xx-fw.c index 0c490e46e48c..34352a0223eb 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-fw.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx-fw.c @@ -29,9 +29,11 @@ * * STAT magics: * READY 0xc55c loader idle in the console loop (this driver) + * DL_RDY 0xc33c loader idle in the flashless loop * START 0xf48f host -> begin download session * ACK 0xf490 loader -> START acknowledged (START + 1) * END 0x3cc3 host -> finalise now (optional, see below) + * RDREG 0xe2c0 host -> register-read command (| index), see below * * Console flash path (STAT=0xc55c) - mxl862xx_flash_firmware(): * @@ -71,7 +73,40 @@ * - never send a slice/chunk count larger than what is outstanding; * - a STAT write is a command only once the loader has left the loop; * - the loader leaves the count in STAT while it programs the chunk, so - * a lingering count does not distinguish "busy" from "verdict". + * a lingering count does not distinguish "busy" from "verdict"; + * - interrupted-download recovery feeds 1 byte at a time (see below). + * + * Interrupted-flash recovery (mxl862xx_rescue_drain): + * A host that dies mid-payload leaves the loader in the receive loop holding + * STAT=0. Feed single 1-byte chunks (one DATA word + STAT=1) until r_remain + * reaches 0; the loader then verifies the (now corrupt) image, publishes its + * verdict and comes back to READY by itself. END is never sent here: while + * r_remain is non-zero it would be consumed as a 15555-byte count, and a + * lingering STAT=1 cannot be told from a chunk still being programmed. + * + * Register-read challenge (non-destructive liveness proof): + * DATA := 0x7c23 (marker); STAT := 0xe2c0|idx + * -> loader returns a runtime word in DATA and re-arms STAT=0xc55c. + * The reply source is loader BSS, not a chip id; used only to prove a live + * mailbox in mxl862xx_rescue_mode_detect(). + * + * The other STAT ready magic, 0xc33c, marks the loader's flashless + * chip-to-chip download mode (MxL86281S 16-port tier); this driver does not + * use it. + * + * Rescue lifecycle (devlink): probe runs mxl862xx_rescue_mode_detect(); a + * wedged loader is drained back to READY by a background self-heal + * (rescue_heal_work), so the long recovery never holds the devlink lock. + * devlink dev info exposes the fw version (the "flashable" signal) only once at + * READY; flash_update returns -EBUSY until then, and reprobes to WSP firmware + * on success. + * + * Notes: + * - Chip id/revision (0xc0d28884/88) are NOT reachable on this channel; they + * need the clause-45 MMD firmware mailbox, which is dead under MCUboot. + * Rescue identity is by SB PDI behaviour only (mxl862xx_rescue_mode_detect). + * - The SMDIO PHY address comes from the device tree; the 0xe1xx register + * offsets are the OTP reset defaults and the only layout supported here. */ #include @@ -104,8 +139,15 @@ /* SB PDI handshake magic (published/consumed via STAT) */ #define MXL862XX_SB_PDI_READY 0xc55c /* loader idle, console loop */ +#define MXL862XX_SB_PDI_DL_READY 0xc33c /* loader idle, flashless loop */ #define MXL862XX_SB_PDI_START 0xf48f #define MXL862XX_SB_PDI_END 0x3cc3 +#define MXL862XX_SB_PDI_RDREG 0xe2c0 /* register-read cmd (| index) */ +#define MXL862XX_SB_PDI_RDREG_MARK 0x7c23 /* marker placed in DATA for RDREG */ + +/* Behavioural presence probe: two distinct 16-bit latches on ADDR/DATA. */ +#define MXL862XX_SB_PDI_PROBE_A 0x5a5a +#define MXL862XX_SB_PDI_PROBE_D 0xa5a5 /* Image verification verdict published in STAT once the receive loop ends */ #define MXL862XX_SB_PDI_VERIFY_OK 0 @@ -124,6 +166,10 @@ #define MXL862XX_FW_WRITE_TIMEOUT_MS 60000 #define MXL862XX_FW_REBOOT_DELAY_MS 5000 #define MXL862XX_FW_REPROBE_DELAY_MS 500 +/* One loader mailbox step: program a 1-byte chunk or service a command */ +#define MXL862XX_SB_PDI_STEP_MS 2000 +/* Covers the loader's END wait, verification and the reset into READY */ +#define MXL862XX_SB_PDI_VERIFY_MS 15000 static int mxl862xx_sb_pdi_reset(struct mxl862xx_priv *priv) { @@ -193,7 +239,8 @@ static int mxl862xx_sb_pdi_flush_last(struct mxl862xx_priv *priv, ret = read_poll_timeout(mxl862xx_smdio_read, val, val < 0 || (u16)val != (u16)data_written, - 10000, MXL862XX_FW_WRITE_TIMEOUT_MS * 1000, + 10000, (MXL862XX_FW_WRITE_TIMEOUT_MS + + MXL862XX_SB_PDI_VERIFY_MS) * 1000, false, priv, MXL862XX_SB_PDI_STAT); if (val < 0) return val; @@ -278,6 +325,357 @@ static struct mxl862xx_reprobe *mxl862xx_reprobe_alloc(struct device *dev) return rp; } +/* Byte-count of each chunk fed to the loader during drain. It MUST be 1: the + * loader only lets us observe "counter == 0", never "counter < step", so any + * step > 1 can subtract past zero, underflow the 32-bit counter and wedge the + * loader for ~2^32 more bytes (a state only a power cycle clears). Stepping by + * 1 walks the counter through every value and is guaranteed to land on zero + * whatever its (possibly odd) start. A 1-byte chunk is a path the loader + * already handles: the normal transfer ends with a single trailing byte for + * odd-sized images (see Step 6). + */ +#define MXL862XX_DRAIN_CHUNK_BYTES 1 + +/* Log the drain's progress every so many bytes; it can run for a long time */ +#define MXL862XX_DRAIN_LOG_BYTES (128 * 1024) + +/* Wait for the loader to ask for the next chunk (STAT 0) or to come back to its + * command loop (STAT READY), and return the STAT value either way. On timeout + * that is whatever STAT still holds, which carries no further information: the + * loader keeps the count we wrote visible while it programs the chunk, and that + * is the same value it publishes as the "image rejected" verdict once the + * counter reaches zero. + * + * STAT 0 is unambiguous here even though it is also the "image verified" + * verdict: by the r_remain == 0 rule the loader leaves the receive loop the + * moment the counter reaches zero, so it is never both inside the loop asking + * for a chunk and publishing a verdict. Once it has left, the next STAT write + * is a command rather than a count, so feeding one more chunk after a verdict + * cannot underflow anything either. + */ +static int mxl862xx_sb_pdi_poll_drain(struct mxl862xx_priv *priv, + unsigned long timeout_ms) +{ + int val; + + read_poll_timeout(mxl862xx_smdio_read, val, + val < 0 || (u16)val == MXL862XX_SB_PDI_READY || + (u16)val == 0, + 50, timeout_ms * 1000, false, + priv, MXL862XX_SB_PDI_STAT); + if (val < 0) + return val; + return (u16)val; +} + +/* The loader is not asking for a chunk: it may still be programming the last + * one, or the counter has reached zero and it is verifying the image and + * resetting into READY. Wait that out -- STAT cannot tell the two apart, and + * guessing would mean writing END into a live receive loop. + * + * Return: 0 once the loader has left the loop, -EAGAIN if it asks for another + * chunk after all, -EIO for a loader still holding the count when the verify + * window expires, or an SMDIO bus error. + */ +static int mxl862xx_rescue_drain_finish(struct mxl862xx_priv *priv, u32 chunk) +{ + struct device *dev = &priv->mdiodev->dev; + int stat; + + stat = mxl862xx_sb_pdi_poll_drain(priv, MXL862XX_SB_PDI_VERIFY_MS); + if (stat < 0) + return stat; + if (stat == MXL862XX_SB_PDI_READY) + return 0; + if (stat == MXL862XX_SB_PDI_VERIFY_BAD) { + dev_err(dev, + "flash: loader stuck after %u chunks, power cycle it\n", + chunk); + return -EIO; + } + if (stat) { + /* A firmware is answering, not the loader: an image survived + * in flash and booted. + */ + dev_info(dev, "flash: firmware booted while draining\n"); + return 0; + } + + return -EAGAIN; +} + +/* Recover a switch whose SB PDI download was interrupted mid-transfer - the + * host died after MCUboot began erasing flash, whether it aborted mid erase or + * mid image-write, both end up in the same place: the payload receive loop. + * There the loader publishes STAT=0, waits for the host to write a byte-count + * to STAT, DMAs that many bytes and subtracts the count from a remaining-bytes + * counter, leaving the loop only when the counter reaches exactly zero. The + * image size died with the host, so we feed single-byte chunks (see + * MXL862XX_DRAIN_CHUNK_BYTES) to walk the counter to zero without underflow. + * The loader then verifies the (now corrupt) image and returns to READY by + * itself, or boots a valid image that happened to survive in flash; either way + * the caller's reprobe classifies the result. Every byte costs about a dozen + * MDIO frames, so a multi-MiB outstanding count takes tens of minutes. + * Returns 0 once the loader has left the receive loop, <0 on error. Does NOT + * recover a counter already underflowed by an earlier oversized-chunk attempt + * - that needs a power cycle. + */ +static int mxl862xx_rescue_drain(struct mxl862xx_priv *priv) +{ + struct device *dev = &priv->mdiodev->dev; + /* Bound: twice the loader's 16 MiB image cap, one byte per chunk. */ + u32 max_chunks = 2u * (16u << 20) / MXL862XX_DRAIN_CHUNK_BYTES; + u32 chunk = 0; + int ret, stat; + + while (chunk < max_chunks) { + /* Teardown can interrupt this long drain. */ + if (test_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags)) + return -ECANCELED; + + stat = mxl862xx_sb_pdi_poll_drain(priv, MXL862XX_SB_PDI_STEP_MS); + if (stat < 0) + return stat; + if (stat == MXL862XX_SB_PDI_READY) + return 0; + + if (stat) { + ret = mxl862xx_rescue_drain_finish(priv, chunk); + if (ret != -EAGAIN) + return ret; + } + + /* Feed one zero byte; reset cleared the write latch. */ + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_CTRL, + MXL862XX_SB_PDI_CTRL_WR); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, 0x0000); + if (ret < 0) + return ret; + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_STAT, + MXL862XX_DRAIN_CHUNK_BYTES); + if (ret < 0) + return ret; + chunk++; + if (!(chunk % MXL862XX_DRAIN_LOG_BYTES)) + dev_info(dev, "flash: drained %u KiB so far\n", + chunk / 1024); + cond_resched(); + } + + dev_err(dev, + "flash: interrupted download did not drain after %u chunks\n", + chunk); + + return -ETIMEDOUT; +} + +/* Background self-heal: drain a wedged download off the devlink flash path, so + * the long recovery never holds the devlink lock. Scheduled from probe; + * reprobes on success so the probe-time detection re-classifies the switch. + */ +void mxl862xx_rescue_heal_work_fn(struct work_struct *work) +{ + struct mxl862xx_priv *priv = + container_of(work, struct mxl862xx_priv, rescue_heal_work); + struct device *dev = &priv->mdiodev->dev; + struct mxl862xx_reprobe *ko; + int ret; + + ret = mxl862xx_rescue_drain(priv); + if (ret == -ECANCELED) + return; + if (ret) { + /* Nothing retries this, so say so: rescue_ready stays clear + * and devlink dev flash reports why it refuses. + */ + dev_err(dev, "flash: download recovery failed: %pe\n", + ERR_PTR(ret)); + WRITE_ONCE(priv->rescue_failed, true); + return; + } + + /* The interrupted transfer is finalised; reprobe so the probe-time + * detection brings the driver up -- flashable in rescue mode if the + * loader is at READY, or normally if a valid image booted. The refs + * are released by the reprobe once it completes, which also decides + * whether it may still run: teardown cannot cancel a work item queued + * here, so the reprobe checks for itself that the device is still + * bound. The flag test below only avoids queueing work that would + * certainly be skipped. + */ + if (test_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags)) + return; + + if (!try_module_get(THIS_MODULE)) + return; + + get_device(dev); + ko = mxl862xx_reprobe_alloc(dev); + if (!ko) { + put_device(dev); + module_put(THIS_MODULE); + /* The loader is at READY and would take an image, but nothing + * will reclassify the switch, so refuse flashing with a real + * error instead of the "retry shortly" that never comes true. + */ + dev_err(dev, "flash: cannot reinitialise after recovery, unbind and rebind to flash\n"); + WRITE_ONCE(priv->rescue_failed, true); + return; + } + + queue_delayed_work(system_long_wq, &ko->work, + msecs_to_jiffies(MXL862XX_FW_REPROBE_DELAY_MS)); +} + +/* Detect MCUboot rescue mode over clause-22 SMDIO alone, so the caller can rule + * the loader out before any C45 API request (which spews CRC errors when no WSP + * firmware answers). A scratch write to ADDR/DATA must latch or the chip is + * absent (-ENODEV); the mailbox is reset first, or a transfer interrupted with + * CTRL=WR would take that write as a payload word instead of latching it. STAT + * then classifies the state, poked destructively only when 0, the one value a + * running firmware never holds: + * + * - 0xc33c: flashless loop; recognised but not supported here. + * - 0xc55c: console loop, if the register-read challenge is serviced. + * - other non-zero: running firmware, left unpoked. + * - 0: wedged receive loop; the 1-byte slice-advance then says whether it + * still needs draining or has just finished. + * + * The scratch write reaches a running firmware too, but lands in mailbox + * registers it does not read, so it is inert there. + * + * Return: MXL862XX_IN_RESCUE, MXL862XX_NOT_RESCUE, -ENODEV when the scratch + * write does not latch, which is a switch that does not answer at all or one + * whose SB PDI window is not at the offsets above, -EOPNOTSUPP for the + * flashless loop, -ENXIO for a READY loader whose mailbox fails the challenge, + * or an SMDIO bus error. + */ +int mxl862xx_rescue_mode_detect(struct mxl862xx_priv *priv) +{ + int stat, dat, ret, rb, a, d; + + /* rescue_ready gates flashing; a wedged loader needs the drain first. */ + WRITE_ONCE(priv->rescue_ready, false); + + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + + /* Presence: a live chip latches the scratch write, an absent one floats. */ + a = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_ADDR, + MXL862XX_SB_PDI_PROBE_A); + if (a < 0) + return a; + d = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, + MXL862XX_SB_PDI_PROBE_D); + if (d < 0) + return d; + a = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_ADDR); + if (a < 0) + return a; + d = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_DATA); + if (d < 0) + return d; + if ((u16)a != MXL862XX_SB_PDI_PROBE_A || + (u16)d != MXL862XX_SB_PDI_PROBE_D) + return -ENODEV; + + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + + stat = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_STAT); + if (stat < 0) + return stat; + + /* Flashless-download loop (MxL86281S tier): this driver does not + * support it -- the console flash path expects READY. Treat it as an + * unusable configuration, like any other unsupported state. + */ + if ((u16)stat == MXL862XX_SB_PDI_DL_READY) + return -EOPNOTSUPP; + + /* Console loop at READY: confirm the live mailbox with the register-read + * challenge (consumes the marker from DATA and re-arms READY). + */ + if ((u16)stat == MXL862XX_SB_PDI_READY) { + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, + MXL862XX_SB_PDI_RDREG_MARK); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_STAT, + MXL862XX_SB_PDI_RDREG); + if (ret < 0) + return ret; + rb = mxl862xx_sb_pdi_poll_stat(priv, MXL862XX_SB_PDI_READY, + MXL862XX_SB_PDI_STEP_MS); + dat = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_DATA); + ret = mxl862xx_sb_pdi_reset(priv); + /* Never re-arming READY fails the challenge like any other + * unserviced command; report it as such rather than as a bus + * timeout the bus never saw. + */ + if (rb == -ETIMEDOUT) + rb = -ENXIO; + if (rb < 0) + return rb; + if (dat < 0) + return dat; + if (ret < 0) + return ret; + if ((u16)dat != MXL862XX_SB_PDI_RDREG_MARK) { + WRITE_ONCE(priv->rescue_ready, true); + return MXL862XX_IN_RESCUE; + } + /* READY but the marker is untouched, so nothing is servicing the + * mailbox. A firmware publishing 0xc55c as its status word looks + * exactly like this, and flashing one would be far worse than + * refusing to bind, so treat it as unusable. + */ + return -ENXIO; + } + + /* Any other non-zero value is a running firmware, not a loader. */ + if (stat) + return MXL862XX_NOT_RESCUE; + + /* STAT == 0: a wedged receive loop takes a 1-byte slice-advance (feed + * one DATA word first, like a drain chunk) and asks for the next chunk + * by publishing 0 again. Had that byte been the last one outstanding, + * the loader leaves the loop instead and returns to READY, having + * consumed the advance -- proof enough of a live mailbox to skip the + * challenge. Anything else means it is still working on it. All three + * are rescue, so this never fails probe; only the drain does. + */ + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_CTRL, + MXL862XX_SB_PDI_CTRL_WR); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, 0x0000); + if (ret < 0) + return ret; + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_STAT, + MXL862XX_DRAIN_CHUNK_BYTES); + if (ret < 0) + return ret; + + rb = mxl862xx_sb_pdi_poll_drain(priv, MXL862XX_SB_PDI_STEP_MS); + if (rb < 0) + return rb; + if (rb == MXL862XX_SB_PDI_READY) + WRITE_ONCE(priv->rescue_ready, true); + + return MXL862XX_IN_RESCUE; +} + /* MCUboot firmware image header */ struct mxl862xx_fw_hdr { __le32 image_type; @@ -353,13 +751,15 @@ static int mxl862xx_flash_firmware(struct mxl862xx_priv *priv, int ret, i; /* Step 1: reboot the firmware into MCUboot rescue mode */ - ret = mxl862xx_api_wrap(priv, SYS_MISC_FW_UPDATE, NULL, 0, - false, false); - if (ret) { - dev_err(&priv->mdiodev->dev, - "flash: FW_UPDATE command failed: %pe\n", - ERR_PTR(ret)); - return ret; + if (!priv->rescue_mode) { + ret = mxl862xx_api_wrap(priv, SYS_MISC_FW_UPDATE, NULL, 0, + false, false); + if (ret) { + dev_err(&priv->mdiodev->dev, + "flash: FW_UPDATE command failed: %pe\n", + ERR_PTR(ret)); + return ret; + } } /* Step 2: wait for bootloader ready */ @@ -541,6 +941,25 @@ int mxl862xx_devlink_info_get(struct dsa_switch *ds, char buf[16]; int ret; + /* No chip-id/revision in MCUboot (needs the firmware MMD mailbox). The + * fw version doubles as the "ready to flash" signal: report it only + * once the loader is at a clean READY, nothing while still draining. + */ + if (priv->rescue_mode) { + if (!READ_ONCE(priv->rescue_ready)) + return 0; + + snprintf(buf, sizeof(buf), "%u.%u.%u", + priv->fw_version.major, priv->fw_version.minor, + priv->fw_version.revision); + ret = devlink_info_version_running_put(req, + DEVLINK_INFO_VERSION_GENERIC_FW, buf); + if (ret) + return ret; + return devlink_info_version_stored_put(req, + DEVLINK_INFO_VERSION_GENERIC_FW, buf); + } + /* A 0 part number means the CHIP ID read failed or the part is * unfused; omit it rather than publish a bogus "0000" that fwupd * would match firmware against -- it then falls back to the driver @@ -614,6 +1033,21 @@ int mxl862xx_devlink_flash_update(struct dsa_switch *ds, return ret; } + /* Refuse to flash while the background self-heal is still draining, and + * for good once it has given up on the loader. + */ + if (READ_ONCE(priv->rescue_failed)) { + NL_SET_ERR_MSG_MOD(extack, + "download recovery failed, power cycle the switch"); + return -EIO; + } + + if (priv->rescue_mode && !READ_ONCE(priv->rescue_ready)) { + NL_SET_ERR_MSG_MOD(extack, + "switch is recovering an interrupted download, retry shortly"); + return -EBUSY; + } + /* The references the reprobe work needs to restore normal operation * must be held before the switch is disturbed; the work itself is * scheduled only once the flash is done (see below). @@ -633,9 +1067,13 @@ int mxl862xx_devlink_flash_update(struct dsa_switch *ds, return -ENOMEM; } - dev_info(ds->dev, "flash: running firmware %u.%u.%u\n", - priv->fw_version.major, priv->fw_version.minor, - priv->fw_version.revision); + if (priv->rescue_mode) + dev_info(ds->dev, + "flash: flashing switch via MCUboot rescue mode\n"); + else + dev_info(ds->dev, "flash: running firmware %u.%u.%u\n", + priv->fw_version.major, priv->fw_version.minor, + priv->fw_version.revision); /* Close ports while the firmware is still alive so the DSA core's * MDB/FDB tracking is drained, and detach user ports so userspace @@ -679,6 +1117,7 @@ int mxl862xx_devlink_flash_update(struct dsa_switch *ds, mutex_lock_nested(&priv->mdiodev->bus->mdio_lock, MDIO_MUTEX_NESTED); priv->block_host = false; + priv->rescue_mode = false; mutex_unlock(&priv->mdiodev->bus->mdio_lock); /* Refresh the cached versions so the flash update only diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-fw.h b/drivers/net/dsa/mxl862xx/mxl862xx-fw.h index e96db19b2888..7cd87c7ad871 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-fw.h +++ b/drivers/net/dsa/mxl862xx/mxl862xx-fw.h @@ -6,7 +6,10 @@ #include struct mxl862xx_priv; +struct work_struct; +int mxl862xx_rescue_mode_detect(struct mxl862xx_priv *priv); +void mxl862xx_rescue_heal_work_fn(struct work_struct *work); int mxl862xx_devlink_info_get(struct dsa_switch *ds, struct devlink_info_req *req, struct netlink_ext_ack *extack); diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-host.c b/drivers/net/dsa/mxl862xx/mxl862xx-host.c index 76f5a78566d9..4df7c83808f6 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-host.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx-host.c @@ -16,6 +16,7 @@ #include #include "mxl862xx.h" #include "mxl862xx-cmd.h" +#include "mxl862xx-fw.h" #include "mxl862xx-host.h" #define CTRL_BUSY_MASK BIT(15) @@ -346,6 +347,11 @@ int mxl862xx_api_wrap(struct mxl862xx_priv *priv, u16 cmd, void *_data, goto out; } + if (priv->rescue_mode) { + ret = -ENODEV; + goto out; + } + if (priv->block_host && cmd != SYS_MISC_FW_UPDATE) { ret = -EBUSY; goto out; @@ -549,9 +555,11 @@ int mxl862xx_smdio_write(struct mxl862xx_priv *priv, u32 addr, u16 val) void mxl862xx_host_init(struct mxl862xx_priv *priv) { INIT_WORK(&priv->crc_err_work, mxl862xx_crc_err_work_fn); + INIT_WORK(&priv->rescue_heal_work, mxl862xx_rescue_heal_work_fn); } void mxl862xx_host_shutdown(struct mxl862xx_priv *priv) { cancel_work_sync(&priv->crc_err_work); + cancel_work_sync(&priv->rescue_heal_work); } diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c b/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c index b689652aa9b9..a5b6940b552e 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c @@ -406,6 +406,8 @@ mxl862xx_phylink_mac_select_pcs(struct phylink_config *config, switch (port) { case 9 ... 16: + if (priv->rescue_mode) + return NULL; if (!MXL862XX_FW_VER_MIN(priv, 1, 0, 84)) { dev_warn_once(dp->ds->dev, "SerDes PCS unsupported on old firmware.\n"); diff --git a/drivers/net/dsa/mxl862xx/mxl862xx.c b/drivers/net/dsa/mxl862xx/mxl862xx.c index fd660669f2eb..720b93533583 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx.c @@ -674,21 +674,66 @@ static int mxl862xx_setup(struct dsa_switch *ds) int n_user_ports = 0, max_vlans; int ingress_finals, vid_rules; struct dsa_port *dp; - int ret, i; - - ret = mxl862xx_reset(priv); - if (ret) - return ret; - - ret = mxl862xx_wait_ready(ds); - if (ret) - return ret; + int ret, i, rescue; + /* The SerDes state is software-only and must exist before anything can + * reach phylink, including a rescue-mode flash clearing rescue_mode + * ahead of the reprobe. + */ mutex_init(&priv->serdes_lock); for (i = 0; i < ARRAY_SIZE(priv->serdes_ports); i++) mxl862xx_setup_pcs(priv, &priv->serdes_ports[i], i + MXL862XX_FIRST_SERDES_PORT); + /* Detect the loader over SB PDI first: it needs no firmware, unlike the + * C45 API (mxl862xx_reset/wait_ready) which spews CRC errors when none + * answers. Touch C45 only once rescue is ruled out. + */ + rescue = mxl862xx_rescue_mode_detect(priv); + if (rescue < 0) { + dev_err(ds->dev, "switch state detection failed: %pe\n", + ERR_PTR(rescue)); + return rescue; + } + + if (rescue == MXL862XX_NOT_RESCUE) { + ret = mxl862xx_reset(priv); + if (ret) + return ret; + + ret = mxl862xx_wait_ready(ds); + if (ret) { + /* the reset may only now have triggered rescue mode */ + rescue = mxl862xx_rescue_mode_detect(priv); + if (rescue < 0) { + dev_err(ds->dev, + "switch not responding after reset: %pe\n", + ERR_PTR(rescue)); + return rescue; + } + if (rescue == MXL862XX_NOT_RESCUE) + return ret; + } + } + + priv->rescue_mode = rescue; + + if (priv->rescue_mode) { + if (priv->rescue_ready) { + dev_warn(ds->dev, + "switch in MCUboot rescue mode, use devlink to flash new firmware\n"); + } else { + /* Drain the wedged download in the background so it + * never holds the devlink lock; info and flash become + * available once ready. + */ + dev_warn(ds->dev, + "switch in MCUboot with an interrupted download, recovering in background\n"); + queue_work(system_long_wq, &priv->rescue_heal_work); + } + return 0; + } + /* Calculate Extended VLAN block sizes. * With VLAN Filter handling VID membership checks: * Ingress: only final catchall rules (PVID insertion, 802.1Q @@ -767,11 +812,21 @@ static int mxl862xx_port_state(struct dsa_switch *ds, int port, bool enable) static int mxl862xx_port_enable(struct dsa_switch *ds, int port, struct phy_device *phydev) { + struct mxl862xx_priv *priv = ds->priv; + + if (priv->rescue_mode) + return 0; + return mxl862xx_port_state(ds, port, true); } static void mxl862xx_port_disable(struct dsa_switch *ds, int port) { + struct mxl862xx_priv *priv = ds->priv; + + if (priv->rescue_mode) + return; + if (mxl862xx_port_state(ds, port, false)) dev_err(ds->dev, "failed to disable port %d\n", port); } @@ -1389,6 +1444,17 @@ static int mxl862xx_port_setup(struct dsa_switch *ds, int port) bool is_cpu_port = dsa_port_is_cpu(dp); int ret; + if (dsa_port_is_dsa(dp)) { + dev_err(ds->dev, "port %d: DSA links not supported\n", port); + return -EOPNOTSUPP; + } + + /* DSA reinits failed user ports as unused; shared ports must + * succeed for the tree to register. + */ + if (priv->rescue_mode) + return dsa_port_is_user(dp) ? -ENODEV : 0; + ret = mxl862xx_port_state(ds, port, false); if (ret) return ret; @@ -1398,11 +1464,6 @@ static int mxl862xx_port_setup(struct dsa_switch *ds, int port) if (dsa_port_is_unused(dp)) return 0; - if (dsa_port_is_dsa(dp)) { - dev_err(ds->dev, "port %d: DSA links not supported\n", port); - return -EOPNOTSUPP; - } - ret = mxl862xx_configure_sp_tag_proto(ds, port, is_cpu_port); if (ret) return ret; @@ -1624,11 +1685,11 @@ static int mxl862xx_port_mdb_del(struct dsa_switch *ds, int port, ether_addr_copy(qparam.mac, mdb->addr); ret = MXL862XX_API_READ(priv, MXL862XX_MAC_TABLEENTRYQUERY, qparam); - /* Post-flash teardown: the firmware and its MAC table are gone, so - * there is nothing left to delete. Outside it, -ENODEV is a bus error - * and must be reported. + /* Post-flash teardown or MCUboot: the firmware and its MAC table are + * gone, so there is nothing left to delete. Outside those, -ENODEV is a + * bus error and must be reported. */ - if (ret == -ENODEV && priv->skip_teardown) + if (ret == -ENODEV && (priv->skip_teardown || priv->rescue_mode)) return 0; if (ret) return ret; @@ -1686,6 +1747,9 @@ static void mxl862xx_port_stp_state_set(struct dsa_switch *ds, int port, struct mxl862xx_priv *priv = ds->priv; int ret; + if (priv->rescue_mode) + return; + switch (state) { case BR_STATE_DISABLED: param.port_state = cpu_to_le32(MXL862XX_STP_PORT_STATE_DISABLE); diff --git a/drivers/net/dsa/mxl862xx/mxl862xx.h b/drivers/net/dsa/mxl862xx/mxl862xx.h index 66989280c59d..991b24aa95af 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx.h +++ b/drivers/net/dsa/mxl862xx/mxl862xx.h @@ -4,7 +4,9 @@ #define __MXL862XX_H #include +#include #include +#include #include #include @@ -14,6 +16,10 @@ struct mxl862xx_priv; #define MXL862XX_FIRST_SERDES_PORT 9 #define MXL862XX_SERDES_SLOTS 4 +/* mxl862xx_rescue_mode_detect() return codes (negative values are errors) */ +#define MXL862XX_NOT_RESCUE 0 +#define MXL862XX_IN_RESCUE 1 + #define MXL862XX_DEFAULT_BRIDGE 0 #define MXL862XX_MAX_BRIDGES 48 #define MXL862XX_MAX_BRIDGE_PORTS 128 @@ -327,6 +333,16 @@ struct mxl862xx_fw_version { * during a firmware flash * @skip_teardown: discard firmware API commands during the teardown * triggered by the post-flash reprobe + * @rescue_mode: switch is in MCUboot; firmware API commands fail fast, + * only clause-22 SMDIO works. Set from setup() before the + * switch is registered and cleared under the MDIO bus lock + * for the benefit of mxl862xx_api_wrap(); other readers + * only need it to be a stable single flag. + * @rescue_ready: (rescue_mode) loader is at a clean READY and will accept + * a flash; false while rescue_heal_work is draining + * @rescue_failed: (rescue_mode) the self-heal gave up; the loader needs a + * power cycle and no flash can be accepted + * @rescue_heal_work: background self-heal draining a wedged download to READY * @stats_work: periodic work item that polls RMON hardware counters * and accumulates them into 64-bit per-port stats */ @@ -334,6 +350,7 @@ struct mxl862xx_priv { struct dsa_switch *ds; struct mdio_device *mdiodev; struct work_struct crc_err_work; + struct work_struct rescue_heal_work; unsigned long flags; u16 drop_meter; struct mxl862xx_fw_version fw_version; @@ -349,6 +366,9 @@ struct mxl862xx_priv { u16 vf_block_size; bool block_host; bool skip_teardown; + bool rescue_mode; + bool rescue_ready; + bool rescue_failed; struct delayed_work stats_work; }; -- 2.55.0