linux/drivers/tty/serial, branch v5.19

serial: 8250: dw: Fix the macro RZN1_UART_xDMACR_8_WORD_BURST

2022-06-30T15:19:11Z

As per RZ/N1 peripheral user manual(r01uh0752ej0100-rzn1-peripheral.pdf) rev 1.0.0 Mar,2019, the value for 8_WORD_BURST is 4(b2,b1=2’b10). This patch fixes the macro as per the user manual. Fixes: aa63d786cea2 ("serial: 8250: dw: Add support for DMA flow controlling devices") Reviewed-by: Phil Edworthy Signed-off-by: Biju Das Link: https://lore.kernel.org/r/20220630083909.4294-1-biju.das.jz@bp.renesas.com Signed-off-by: Greg Kroah-Hartman

serial: mvebu-uart: correctly report configured baudrate value

2022-06-30T15:17:31Z

Functions tty_termios_encode_baud_rate() and uart_update_timeout() should be called with the baudrate value which was set to hardware. Linux then report exact values via ioctl(TCGETS2) to userspace. Change mvebu_uart_baud_rate_set() function to return baudrate value which was set to hardware and propagate this value to above mentioned functions. With this change userspace would see precise value in termios c_ospeed field. Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate") Cc: stable Reviewed-by: Ilpo Järvinen Signed-off-by: Pali Rohár Link: https://lore.kernel.org/r/20220628100922.10717-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: 8250: Fix PM usage_count for console handover

2022-06-30T15:17:31Z

When console is enabled, univ8250_console_setup() calls serial8250_console_setup() before .dev is set to uart_port. Therefore, it will not call pm_runtime_get_sync(). Later, when the actual driver is going to take over univ8250_console_exit() is called. As .dev is already set, serial8250_console_exit() makes pm_runtime_put_sync() call with usage count being zero triggering PM usage count warning (extra debug for univ8250_console_setup(), univ8250_console_exit(), and serial8250_register_ports()): [ 0.068987] univ8250_console_setup ttyS0 nodev [ 0.499670] printk: console [ttyS0] enabled [ 0.717955] printk: console [ttyS0] printing thread started [ 1.960163] serial8250_register_ports assigned dev for ttyS0 [ 1.976830] printk: console [ttyS0] disabled [ 1.976888] printk: console [ttyS0] printing thread stopped [ 1.977073] univ8250_console_exit ttyS0 usage:0 [ 1.977075] serial8250 serial8250: Runtime PM usage count underflow! [ 1.977429] dw-apb-uart.6: ttyS0 at MMIO 0x4010006000 (irq = 33, base_baud = 115200) is a 16550A [ 1.977812] univ8250_console_setup ttyS0 usage:2 [ 1.978167] printk: console [ttyS0] printing thread started [ 1.978203] printk: console [ttyS0] enabled To fix the issue, call pm_runtime_get_sync() in serial8250_register_ports() as soon as .dev is set for an uart_port if it has console enabled. This problem became apparent only recently because 82586a721595 ("PM: runtime: Avoid device usage count underflows") added the warning printout. I confirmed this problem also occurs with v5.18 (w/o the warning printout, obviously). Fixes: bedb404e91bb ("serial: 8250_port: Don't use power management for kernel console") Cc: stable Tested-by: Tony Lindgren Reviewed-by: Andy Shevchenko Reviewed-by: Tony Lindgren Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/b4f428e9-491f-daf2-2232-819928dc276e@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: fix return error code in serial8250_request_std_resource()

2022-06-30T15:15:47Z

If port->mapbase = NULL in serial8250_request_std_resource() , it need return a error code instead of 0. If uart_set_info() fail to request new regions by serial8250_request_std_resource() but the return value of serial8250_request_std_resource() is 0, The system incorrectly considers that the resource application is successful and does not attempt to restore the old setting. A null pointer reference is triggered when the port resource is later invoked. Signed-off-by: Yi Yang Cc: stable Link: https://lore.kernel.org/r/20220628083515.64138-1-yiyang13@huawei.com Signed-off-by: Greg Kroah-Hartman

serial: stm32: Clear prev values before setting RTS delays

2022-06-30T15:15:31Z

The code lacks clearing of previous DEAT/DEDT values. Thus, changing values on the fly results in garbage delays tending towards the maximum value as more and more bits are ORed together. (Leaving RS485 mode would have cleared the old values though). Fixes: 1bcda09d2910 ("serial: stm32: add support for RS485 hardware control mode") Cc: stable Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220627150753.34510-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: Fix __stop_tx() & DMA Tx restart races

2022-06-27T12:47:57Z

Commit e8ffbb71f783 ("serial: 8250: use THRE & __stop_tx also with DMA") changed __dma_tx_complete() to enable THRI that is cleared in __stop_tx() once THRE is asserted as UART runs out bits to transmit. It is possible, however, that more data arrives in between in which case serial8250_tx_dma() resumes Tx. THRI is not supposed to be on during DMA Tx because DMA is based on completion handler, therefore THRI must be cleared unconditionally in serial8250_tx_dma(). When Tx is about to start, another race window exists with serial8250_handle_irq() leading to a call into __stop_tx() while the Tx has already been resumed: __tx_complete(): -> spin_lock(port->lock) -> dma->tx_running = 0 -> serial8250_set_THRI() -> spin_unlock(port->lock) uart_start(): serial8250_handle_irq(): -> spin_lock(port->lock) -> serial8250_tx_dma(): -> dma->tx_running = 1 -> spin_unlock(port->lock) -> spin_lock(port->lock) -> __stop_tx() Close this race by checking !dma->tx_running before calling into __stop_tx(). Fixes: e8ffbb71f783 ("serial: 8250: use THRE & __stop_tx also with DMA") Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220615090651.15340-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: pl011: UPSTAT_AUTORTS requires .throttle/unthrottle

2022-06-27T12:47:02Z

The driver must provide throttle and unthrottle in uart_ops when it sets UPSTAT_AUTORTS. Add them using existing stop_rx & enable_interrupts functions. Fixes: 2a76fa283098 (serial: pl011: Adopt generic flag to store auto RTS status) Cc: stable Cc: Lukas Wunner Reported-by: Nuno Gonçalves Tested-by: Nuno Gonçalves Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220614075637.8558-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung_tty: set dma burst_size to 1

2022-06-27T12:46:39Z

The src_maxburst and dst_maxburst have been changed to 1 but the settings of the UCON register aren't changed yet. They should be changed as well according to the dmaengine slave config. Fixes: aa2f80e752c7 ("serial: samsung: fix maxburst parameter for DMA transactions") Cc: stable Cc: Marek Szyprowski Reviewed-by: Krzysztof Kozlowski Signed-off-by: Chanho Park Link: https://lore.kernel.org/r/20220627065113.139520-1-chanho61.park@samsung.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: dw: enable using pdata with ACPI

2022-06-27T12:45:49Z

Commit ffd381445eac ("serial: 8250: dw: Move the USR register to pdata") caused NULL-pointer dereference when booting with ACPI by unconditional usage of the recently added pdata. In order to fix that and prevent similar issues in future, hook the default version of this structure in dw8250_acpi_match table. While at it, sort all entries alphabetically. Fixes: ffd381445eac ("serial: 8250: dw: Move the USR register to pdata") Reviewed-by: Ilpo Järvinen Reviewed-by: Andy Shevchenko Signed-off-by: Marcin Wojtas Link: https://lore.kernel.org/r/20220620121046.1307412-1-mw@semihalf.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: Store to lsr_save_flags after lsr read

2022-06-10T11:52:19Z

Not all LSR register flags are preserved across reads. Therefore, LSR readers must store the non-preserved bits into lsr_save_flags. This fix was initially mixed into feature commit f6f586102add ("serial: 8250: Handle UART without interrupt on TEMT using em485"). However, that feature change had a flaw and it was reverted to make room for simpler approach providing the same feature. The embedded fix got reverted with the feature change. Re-add the lsr_save_flags fix and properly mark it's a fix. Link: https://lore.kernel.org/all/1d6c31d-d194-9e6a-ddf9-5f29af829f3@linux.intel.com/T/#m1737eef986bd20cf19593e344cebd7b0244945fc Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250") Cc: stable Acked-by: Uwe Kleine-König Signed-off-by: Uwe Kleine-König Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/f4d774be-1437-a550-8334-19d8722ab98c@linux.intel.com Signed-off-by: Greg Kroah-Hartman