kernel/linux.git/drivers/tty/serial/8250, branch v4.19.112

serial: 8250_exar: add support for ACCES cards

2020-03-11T13:15:02+00:00

commit 10c5ccc3c6d32f3d7d6c07de1d3f0f4b52f3e3ab upstream. Add ACCES VIDs and PIDs that use the Exar chips Signed-off-by: Jay Dolan Cc: stable Link: https://lore.kernel.org/r/20200305140504.22237-1-jay.dolan@accesio.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: Check UPF_IRQ_SHARED in advance

2020-02-28T15:38:48+00:00

commit 7febbcbc48fc92e3f33863b32ed715ba4aff18c4 upstream. The commit 54e53b2e8081 ("tty: serial: 8250: pass IRQ shared flag to UART ports") nicely explained the problem: ---8<---8<--- On some systems IRQ lines between multiple UARTs might be shared. If so, the irqflags have to be configured accordingly. The reason is: The 8250 port startup code performs IRQ tests *before* the IRQ handler for that particular port is registered. This is performed in serial8250_do_startup(). This function checks whether IRQF_SHARED is configured and only then disables the IRQ line while testing. This test is performed upon each open() of the UART device. Imagine two UARTs share the same IRQ line: On is already opened and the IRQ is active. When the second UART is opened, the IRQ line has to be disabled while performing IRQ tests. Otherwise an IRQ might handler might be invoked, but the IRQ itself cannot be handled, because the corresponding handler isn't registered, yet. That's because the 8250 code uses a chain-handler and invokes the corresponding port's IRQ handling routines himself. Unfortunately this IRQF_SHARED flag isn't configured for UARTs probed via device tree even if the IRQs are shared. This way, the actual and shared IRQ line isn't disabled while performing tests and the kernel correctly detects a spurious IRQ. So, adding this flag to the DT probe solves the issue. Note: The UPF_SHARE_IRQ flag is configured unconditionally. Therefore, the IRQF_SHARED flag can be set unconditionally as well. Example stack trace by performing `echo 1 > /dev/ttyS2` on a non-patched system: |irq 85: nobody cared (try booting with the "irqpoll" option) | [...] |handlers: |[] irq_default_primary_handler threaded [] serial8250_interrupt |Disabling IRQ #85 ---8<---8<--- But unfortunately didn't fix the root cause. Let's try again here by moving IRQ flag assignment from serial_link_irq_chain() to serial8250_do_startup(). This should fix the similar issue reported for 8250_pnp case. Since this change we don't need to have custom solutions in 8250_aspeed_vuart and 8250_of drivers, thus, drop them. Fixes: 1c2f04937b3e ("serial: 8250: add IRQ trigger support") Reported-by: Li RongQing Cc: Kurt Kanzenbach Cc: Vikram Pandita Signed-off-by: Andy Shevchenko Cc: stable Acked-by: Kurt Kanzenbach Link: https://lore.kernel.org/r/20200211135559.85960-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: 8250_bcm2835aux: Fix line mismatch on driver unbind

2020-02-01T09:37:03+00:00

commit dc76697d7e933d5e299116f219c890568785ea15 upstream. Unbinding the bcm2835aux UART driver raises the following error if the maximum number of 8250 UARTs is set to 1 (via the 8250.nr_uarts module parameter or CONFIG_SERIAL_8250_RUNTIME_UARTS): (NULL device *): Removing wrong port: a6f80333 != fa20408b That's because bcm2835aux_serial_probe() retrieves UART line number 1 from the devicetree and stores it in data->uart.port.line, while serial8250_register_8250_port() instead uses UART line number 0, which is stored in data->line. On driver unbind, bcm2835aux_serial_remove() uses data->uart.port.line, which contains the wrong number. Fix it. The issue does not occur if the maximum number of 8250 UARTs is >= 2. Fixes: bdc5f3009580 ("serial: bcm2835: add driver for bcm2835-aux-uart") Signed-off-by: Lukas Wunner Cc: stable@vger.kernel.org # v4.6+ Cc: Martin Sperl Reviewed-by: Nicolas Saenz Julienne Tested-by: Nicolas Saenz Julienne Link: https://lore.kernel.org/r/912ccf553c5258135c6d7e8f404a101ef320f0f4.1579175223.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

serial: 8250: Fix serial8250 initialization crash

2019-12-05T08:21:06+00:00

[ Upstream commit 352c4cf40c4a7d439fa5d30aa2160f54b394da82 ] The initialization code of interrupt backoff work might reference NULL pointer and cause the following crash, if no port was found. [ 10.017727] CPU 0 Unable to handle kernel paging request at virtual address 000001b0, epc == 807088e0, ra == 8070863c ---- snip ---- [ 11.704470] [<807088e0>] serial8250_register_8250_port+0x318/0x4ac [ 11.747251] [<80708d74>] serial8250_probe+0x148/0x1c0 [ 11.789301] [<80728450>] platform_drv_probe+0x40/0x94 [ 11.830515] [<807264f8>] really_probe+0xf8/0x318 [ 11.870876] [<80726b7c>] __driver_attach+0x110/0x12c [ 11.910960] [<80724374>] bus_for_each_dev+0x78/0xcc [ 11.951134] [<80725958>] bus_add_driver+0x200/0x234 [ 11.989756] [<807273d8>] driver_register+0x84/0x148 [ 12.029832] [<80d72f84>] serial8250_init+0x138/0x198 [ 12.070447] [<80100e6c>] do_one_initcall+0x5c/0x2a0 [ 12.110104] [<80d3a208>] kernel_init_freeable+0x370/0x484 [ 12.150722] [<80a49420>] kernel_init+0x10/0xf8 [ 12.191517] [<8010756c>] ret_from_kernel_thread+0x14/0x1c This patch makes sure the initialization code can be reached only if a port is found. Fixes: 6d7f677a2afa ("serial: 8250: Rate limit serial port rx interrupts during input overruns") Signed-off-by: He Zhe Reviewed-by: Darwin Dingel Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250: Rate limit serial port rx interrupts during input overruns

2019-12-05T08:20:25+00:00

[ Upstream commit 6d7f677a2afa1c82d7fc7af7f9159cbffd5dc010 ] When a serial port gets faulty or gets flooded with inputs, its interrupt handler starts to work double time to get the characters to the workqueue for the tty layer to handle them. When this busy time on the serial/tty subsystem happens during boot, where it is also busy on the userspace trying to initialise, some processes can continuously get preempted and will be on hold until the interrupts subside. The fix is to backoff on processing received characters for a specified amount of time when an input overrun is seen (received a new character before the previous one is processed). This only stops receive and will continue to transmit characters to serial port. After the backoff period is done, it receive will be re-enabled. This is optional and will only be enabled by setting 'overrun-throttle-ms' in the dts. Signed-off-by: Darwin Dingel Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

8250-men-mcb: fix error checking when get_num_ports returns -ENODEV

2019-11-10T10:27:25+00:00

[ Upstream commit f50b6805dbb993152025ec04dea094c40cc93a0c ] The current checking for failure on the number of ports fails when -ENODEV is returned from the call to get_num_ports. Fix this by making num_ports and loop counter i signed rather than unsigned ints. Also add check for num_ports being less than zero to check for -ve error returns. Addresses-Coverity: ("Unsigned compared against 0") Fixes: e2fea54e4592 ("8250-men-mcb: add support for 16z025 and 16z057") Signed-off-by: Colin Ian King Reviewed-by: Michael Moese Link: https://lore.kernel.org/r/20191013220016.9369-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250: Fix TX interrupt handling condition

2019-07-31T05:27:00+00:00

[ Upstream commit db1b5bc047b3cadaedab3826bba82c3d9e023c4b ] Interrupt handler checked THRE bit (transmitter holding register empty) in LSR to detect if TX fifo is empty. In case when there is only receive interrupts the TX handling got called because THRE bit in LSR is set when there is no transmission (FIFO empty). TX handling caused TX stop, which in RS-485 half-duplex mode actually resets receiver FIFO. This is not desired during reception because of possible data loss. The fix is to check if THRI is set in IER in addition of the TX fifo status. THRI in IER is set when TX is started and cleared when TX is stopped. This ensures that TX handling is only called when there is really transmission on going and an interrupt for THRE and not when there are only RX interrupts. Signed-off-by: Kimmo Rautkoski Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

Revert "serial: 8250: Don't service RX FIFO if interrupts are disabled"

2019-07-14T06:11:19+00:00

commit 3f2640ed7be838c3f05c0d2b0f7c7508e7431e48 upstream. This reverts commit 2e9fe539108320820016f78ca7704a7342788380. Reading LSR unconditionally but processing the error flags only if UART_IIR_RDI bit was set before in IIR may lead to a loss of transmission error information on UARTs where the transmission error flags are cleared by a read of LSR. Information are lost in case an error is detected right before the read of LSR while processing e.g. an UART_IIR_THRI interrupt. Signed-off-by: Oliver Barta Reviewed-by: Andy Shevchenko Fixes: 2e9fe5391083 ("serial: 8250: Don't service RX FIFO if interrupts are disabled") Cc: stable Signed-off-by: Greg Kroah-Hartman

dmaengine: idma64: Use actual device for DMA transfers

2019-06-15T09:54:10+00:00

[ Upstream commit 5ba846b1ee0792f5a596b9b0b86d6e8cdebfab06 ] Intel IOMMU, when enabled, tries to find the domain of the device, assuming it's a PCI one, during DMA operations, such as mapping or unmapping. Since we are splitting the actual PCI device to couple of children via MFD framework (see drivers/mfd/intel-lpss.c for details), the DMA device appears to be a platform one, and thus not an actual one that performs DMA. In a such situation IOMMU can't find or allocate a proper domain for its operations. As a result, all DMA operations are failed. In order to fix this, supply parent of the platform device to the DMA engine framework and fix filter functions accordingly. We may rely on the fact that parent is a real PCI device, because no other configuration is present in the wild. Signed-off-by: Andy Shevchenko Acked-by: Mark Brown Acked-by: Greg Kroah-Hartman [for tty parts] Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin

serial: 8250_pxa: honor the port number from devicetree

2019-04-05T20:33:01+00:00

[ Upstream commit fe9ed6d2483fda55465f32924fb15bce0fac3fac ] Like the other OF-enabled drivers, use the port number from the firmware if the devicetree specifies an alias: aliases { ... serial2 = &uart2; /* Should be ttyS2 */ } This is how the deprecated pxa.c driver behaved, switching to 8250_pxa messes up the numbering. Signed-off-by: Lubomir Rintel Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin