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* tty: Use flow-control char function on closing pathIlpo Järvinen2022-06-101-9/+4
| | | | | | | | | | | | | | | | | | | | | | | | | Use n_tty_receive_char_flow_ctrl also on the closing path. This makes the code cleaner and consistent. However, there a small change of regression! The earlier closing path has a small difference compared with the normal receive path. If START_CHAR and STOP_CHAR are equal, their precedence is different depending on which path a character is processed. I don't know whether this difference was intentional or not, and if equal START_CHAR and STOP_CHAR is actually used anywhere. But it feels not so useful corner case. While this change would logically belong to those earlier changes, having a separate patch for this is useful. If this regresses, bisect can pinpoint this change rather than the large patch. Also, this change is not necessary to minimal fix for the issue addressed in the previous patch. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606153652.63554-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Implement lookahead to process XON/XOFF timelyIlpo Järvinen2022-06-103-25/+146
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When tty is not read from, XON/XOFF may get stuck into an intermediate buffer. As those characters are there to do software flow-control, it is not very useful. In the case where neither end reads from ttys, the receiving ends might not be able receive the XOFF characters and just keep sending more data to the opposite direction. This problem is almost guaranteed to occur with DMA which sends data in large chunks. If TTY is slow to process characters, that is, eats less than given amount in receive_buf, invoke lookahead for the rest of the chars to process potential XON/XOFF characters. We need to keep track of how many characters have been processed by the lookahead to avoid processing the flow control char again on the normal path. Bookkeeping occurs parallel on two layers (tty_buffer and n_tty) to avoid passing the lookahead_count through the whole call chain. When a flow-control char is processed, two things must occur: a) it must not be treated as normal char b) if not yet processed, flow-control actions need to be taken The return value of n_tty_receive_char_flow_ctrl() tells caller a), and b) is kept internal to n_tty_receive_char_flow_ctrl(). If characters were previous looked ahead, __receive_buf() makes two calls to the appropriate n_tty_receive_buf_* function. First call is made with lookahead_done=true for the characters that were subject to lookahead earlier and then with lookahead=false for the new characters. Either of the calls might be skipped when it has no characters to handle. Reported-by: Gilles Buloz <gilles.buloz@kontron.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606153652.63554-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Remove serial_rs485 sanitization from em485Ilpo Järvinen2022-06-101-16/+2
| | | | | | | | | | | | | | | | | | | | Serial core handles serial_rs485 sanitization. When em485 init fails, there are two possible paths of entry: 1) uart_rs485_config (init path) that fully clears port->rs485 on error. 2) ioctl path with a pre-existing, valid port->rs485 unto which the kernel falls back on error and port->rs485 should therefore be kept untouched. The temporary rs485 struct is not returned to userspace in case of error so its flag don't matter. ...Thus SER_RS485_ENABLED clearing on error can/should be dropped. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-37-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sc16is7xx: Remove serial_rs485 assignmentIlpo Järvinen2022-06-101-1/+0
| | | | | | | | | | Serial core handles serial_rs485 assignment. It is safe to remove this assignment because sc16is7xx_reg_proc() takes port.lock at start (and sc16is7xx_reconf_rs485() would too). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-36-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: mcf: Remove serial_rs485 assignmentIlpo Järvinen2022-06-101-1/+0
| | | | | | | | Serial core handles serial_rs485 assignment. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-35-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_exar: Remove serial_rs485 assignmentIlpo Järvinen2022-06-101-2/+0
| | | | | | | | Serial core handles serial_rs485 assignment. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-34-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: max310x: Remove serial_rs485 sanitizationIlpo Järvinen2022-06-101-2/+0
| | | | | | | | Serial core handles serial_rs485 sanitization. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-33-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: imx: Remove serial_rs485 sanitizationIlpo Järvinen2022-06-101-4/+0
| | | | | | | | | | The driver provides different rs485_supported for the case where RTS is not available making it unnecessary to handle it in imx_uart_rs485_config. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-32-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: fsl_lpuart: Call core's sanitization and remove custom oneIlpo Järvinen2022-06-101-17/+0
| | | | | | | | | | | | | | | Serial core handles serial_rs485 sanitization. Remove custom sanitization from lpuart_config_rs485. This change loses dev_err when SER_RS485_RX_DURING_TX is set due to incorrect configuration. Other drivers do not do similar prinout for full-duplex case and it should be done in serial core if it is desirable to notify on this condition. Personally, I doesn't see it important because the kernel gracefully downgrades to half-duplex. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-31-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: pl011: Remove serial_rs485 sanitizationIlpo Järvinen2022-06-101-5/+0
| | | | | | | | Serial core handles serial_rs485 sanitization. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-30-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_pci: Remove serial_rs485 sanitizationIlpo Järvinen2022-06-101-14/+0
| | | | | | | | Serial core handles serial_rs485 sanitization and copying rs485 struct. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-29-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: lpc18xx: Remove serial_rs485 sanitizationIlpo Järvinen2022-06-101-13/+0
| | | | | | | | Serial core handles serial_rs485 sanitization and copying rs485 struct. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-28-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_fintek: Remove serial_rs485 sanitizationIlpo Järvinen2022-06-101-14/+0
| | | | | | | | Serial core handles serial_rs485 sanitization and copying rs485 struct. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-27-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_dwlib: Remove serial_rs485 sanitizationIlpo Järvinen2022-06-101-10/+0
| | | | | | | | | | Serial core handles serial_rs485 sanitization and rs485 struct assignment. As serial_rs485 is already clear for the non-RS485 case by serial core, there no need to clear flags in the driver. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-26-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: return -EINVAL for non-legacy RS485 flagsIlpo Järvinen2022-06-101-0/+24
| | | | | | | | | | | | | | | In order to be add new flags more cleanly and safely, return -EINVAL from TIOCSRS485 ioctl for the flags bits which are not among the current legacy ones. This might cause a regression for userspace as those non-flag bits do not currently trigger -EINVAL. However, it would only occur if the userspace is sending garbage bits so perhaps we'll get away with this change. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-25-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: Clear rs485 struct when non-RS485 mode is setIlpo Järvinen2022-06-101-1/+11
| | | | | | | | | | | | | | | | | | | | When SER_RS485_ENABLED is not set, having any other flag/field set in serial_rs485 struct does not have an effect different from not having them set. Thus, make the serial_rs485 struct also match the behavior for all flags, not just SER_RS485_ENABLED. Some drivers do similar clearing of rs485 struct in their rs485_config() already, but not all. This change makes the behavior consistent across drivers. Don't try to validate rs485 struct further when no RS485 is requested, this silences some bogus warnings. This change has (minor) userspace visible impact. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-24-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: Sanitize rs485_structIlpo Järvinen2022-06-101-4/+29
| | | | | | | | | | | | | | | | | | | | | Sanitize serial_rs485 struct before calling into rs485_setup. The drivers provide supported_rs485 to help sanitization of the fields. If neither of SER_RS485_RTS_ON_SEND or SER_RS485_RTS_AFTER_SEND supported, don't pretend they can be set to sane settings but clear them both instead. If only one of them is supported it may look tempting to use the one driver supports to set the other, however, the userspace does not have that information readily available so it wouldn't be helpful. While adjusting the documentation, remove also the claim that TIOCGRS485 would call driver specific code. In reality, it does nothing else than copies the stored serial_rs485 structure from uart_port to userspace. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-23-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: stm32: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+8
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-22-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sc16is7xx: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+7
| | | | | | | | | | | | | | | | Add information on supported serial_rs485 features. This driver does not support delay_rts_after_send but the pre-existing behavior is to return -EINVAL if delay_rts_after_send is non-zero. In contrast, other drivers that do not support delay_rts_after_send either zero delay_rts_after_send or do not care (leave the inaccurate value). As changing this would cause userspace visible impact, the change is not attempted here. But perhaps it should be still tried (maybe nobody finds that kind of API oddity significant)? Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-21-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: omap: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+8
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-20-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: mcf: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+6
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-19-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: max310x: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+7
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-18-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: imx: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+13
| | | | | | | | | | | | | | Add information on supported serial_rs485 features. In the case where RTS is lacking, RS485 cannot be enabled so provide zero rs485_supported for that case. Perhaps it would make sense to not provide rs485_config() at all in that case but such a change would have userspace visible impact/change in behavior so this patch does not attempt it. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-17-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: fsl_lpuart: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+6
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-16-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: atmel: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+7
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-15-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: ar933x: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+7
| | | | | | | | | | | | | | Add information on supported serial_rs485 features. In the case where RTS is lacking, RS485 cannot be enabled so provide zero rs485_supported for that case. Perhaps it would make sense to not provide rs485_config() at all in that case but such a change would have userspace visible impact/change in behavior so this patch does not attempt it. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-14-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: pl011: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+8
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-13-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_pci: Fill in rs485_supported for pci_fintekIlpo Järvinen2022-06-101-0/+6
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-12-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_of: Use serial8250_em485_supportedIlpo Järvinen2022-06-101-0/+1
| | | | | | | | 8250_of uses em485, fill in rs485_supported accordingly. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-11-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_lpc18cc: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+7
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-10-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_fintek: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+15
| | | | | | | | | | Add information on supported serial_rs485 features. Differentiate based on which port is in question. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-9-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_exar: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+12
| | | | | | | | Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-8-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_dwlib: Fill in rs485_supportedIlpo Järvinen2022-06-101-0/+7
| | | | | | | | | Add information on supported serial_rs485 features. When the driver is using em485, take advantage of serial8250_em485_supported. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_bcm2835aux: Use serial8250_em485_supportedIlpo Järvinen2022-06-101-0/+1
| | | | | | | | bcm2835aux uses em485, fill in rs485_supported accordingly. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-6-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Create serial8250_em485_supported for em485 usersIlpo Järvinen2022-06-102-0/+9
| | | | | | | | | Create serial8250_em485_supported for the serial_rs485 features supported by the em485 framework. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-5-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: Add rs485_supported to uart_portIlpo Järvinen2022-06-101-0/+1
| | | | | | | | | | Preparing to move serial_rs485 struct sanitization into serial core, each driver has to provide what fields/flags it supports. This information is pointed into by rs485_supported. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: Move serial_rs485 sanitization into separate functionIlpo Järvinen2022-06-101-25/+30
| | | | | | | | | | | Add uart_sanitize_serial_rs485() function for sanitizing serial_rs485 structure fields. No functional changes. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: Add uart_rs485_config()Ilpo Järvinen2022-06-105-7/+11
| | | | | | | | | | | | | | | | A few serial drivers make a call to rs485_config() themselves (all these seem to relate to init). Convert them all to use a common helper which makes it easy to make adjustments on tasks related to it as serial_rs485 struct sanitization is going to be added. In pci_fintek_setup() (in 8250_pci.c), the rs485_config() call was made with NULL, however, it can be changed to pass uart_port's rs485 struct. No other callers should pass NULL into rs485_config() so the NULL check can now be eliminated. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_dw: Store LSR into lsr_saved_flags in dw8250_tx_wait_empty()Ilpo Järvinen2022-06-101-0/+3
| | | | | | | | | | | | | | | | Make sure LSR flags are preserved in dw8250_tx_wait_empty(). This function is called from a low-level out function and therefore cannot call serial_lsr_in() as it would lead to infinite recursion. It is borderline if the flags need to be saved here at all since this code relates to writing LCR register which usually implies no important characters should be arriving. Fixes: 914eaf935ec7 ("serial: 8250_dw: Allow TX FIFO to drain before writing to UART_LCR") Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220608095431.18376-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250_dw: Use serial_lsr_in() in dw8250_handle_irq()Ilpo Järvinen2022-06-101-2/+2
| | | | | | | | | | | | | | | | dw8250_handle_irq() reads LSR under a few conditions, convert both to use serial_lsr_in() in order to preserve LSR flags properly across reads. Fixes: 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt") Fixes: aa63d786cea2 ("serial: 8250: dw: Add support for DMA flow controlling devices") Cc: Douglas Anderson <dianders@chromium.org> Cc: Phil Edworthy <phil.edworthy@renesas.com> Cc: Miquel Raynal <miquel.raynal@bootlin.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220608095431.18376-6-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Adjust misleading LSR related commentIlpo Järvinen2022-06-101-3/+5
| | | | | | | | | | | | | | | | | | | | serial8250_rx_chars() has max_count based character limit. If it triggers, the function returns the old LSR value (and it has never returned only flags which were not handled). Adjust the comment to match behavior and warn about which flags can be depended on. I'd have moved LSR read before LSR read and used serial_lsr_in() also here but I came across an old discussion about the topic. That discussion generated commit d22f8f10683c ("serial: 8250: Fix lost rx state") so I left the code as it is (it works as long as the callers only use a subset of the LSR flags which holds true today) and changed the comment instead. Link: https://www.spinics.net/lists/linux-serial/msg16220.html Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220608095431.18376-5-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Get preserved flags using serial_lsr_in()Ilpo Järvinen2022-06-101-1/+1
| | | | | | | | | | | | | | | | | | | | | serial8250_handle_irq() assumes it's the first to read LSR register. However, there are 8250 drivers which perform LSR read in their own irq handler prior to calling serial8250_handle_irq(). As not all flags are preserved across LSR reads, use serial_lsr_in() helper to get all the preserved flags. This commit might fix other commits too besides the ones for DW UART mentioned below. It's just not clear to me which of the other devices clear some of the LSR flags on read. AFAIK, nobody has complained about this problem (either against DW or other devices) so it might not have that bad impact in the end. Fixes: 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt") Fixes: aa63d786cea2 ("serial: 8250: dw: Add support for DMA flow controlling devices") Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220608095431.18376-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Create serial_lsr_in()Ilpo Järvinen2022-06-103-13/+25
| | | | | | | | | | | LSR register readers need to be careful in order to not lose bits that are not preserved across reads. Create a helper that takes care of storing the non-preserved bits into lsr_save_flags. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220608095431.18376-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Store to lsr_save_flags after lsr readIlpo Järvinen2022-06-101-0/+2
| | | | | | | | | | | | | | | | | | | | | | 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") Co-developed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220608095431.18376-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: handle __start_tx() call in start_tx()Ilpo Järvinen2022-06-101-11/+10
| | | | | | | | | | | | | | As either start_tx_rs485() or start_tx() calls __start_tx() as the last line of their logic, it makes sense to just move that call into start_tx(). When start_tx_rs485() wants to defer tx using timer, return false so start_tx() can return based on it. Reorganize em485 code in serial8250_start_tx() so that the return can be shared for the cases where tx start is deferred. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220607084154.8172-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: kill __do_stop_tx()Ilpo Järvinen2022-06-101-7/+3
| | | | | | | | | | There seems to be little reason for __do_stop_tx() to exits on its own. It is rather simple and is only called from __stop_tx(). Thus, move its logic into __stop_tx(). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220607084154.8172-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: vt: convert sysfs snprintf to sysfs_emitXuezhi Zhang2022-06-101-2/+2
| | | | | | | | | | | | Fix the following coccicheck warnings: drivers/tty/vt/vt.c:3942:8-16: WARNING: use scnprintf or sprintf drivers/tty/vt/vt.c:3950:8-16: WARNING: use scnprintf or sprintf Signed-off-by: Xuezhi Zhang <zhangxuezhi1@coolpad.com> Link: https://lore.kernel.org/r/20220531072814.34999-1-zhangxuezhi1@coolpad.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: max310x: implement I2C supportCosmin Tanislav2022-06-102-1/+135
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I2C implementation on this chip has a few key differences compared to SPI, as described in previous patches. * extended register space access needs no extra logic * slave address is used to select which UART to communicate with To accommodate these differences, add an I2C interface config, set the RevID register address and implement an empty method for setting the GlobalCommand register, since no special handling is needed for the extended register space. To handle the port-specific slave address, create an I2C dummy device for each port, except the base one (UART0), which is expected to be the one specified in firmware, and create a regmap for each I2C device. Add minimum and maximum slave addresses to each devtype for sanity checking. Also, use a separate regmap config with no write_flag_mask, since I2C has a R/W bit in its slave address, and set the max register to the address of the RevID register, since the extended register space needs no extra logic. Finally, add the I2C driver. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com> Link: https://lore.kernel.org/r/20220605144659.4169853-5-demonsingur@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: max310x: make accessing revision id interface-agnosticCosmin Tanislav2022-06-101-10/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | SPI can only use 5 address bits, since one bit is reserved for specifying R/W and 2 bits are used to specify the UART port. To access registers that have addresses past 0x1F, an extended register space can be enabled by writing to the GlobalCommand register (address 0x1F). I2C uses 8 address bits. The R/W bit is placed in the slave address, and so is the UART port. Because of this, registers that have addresses higher than 0x1F can be accessed normally. To access the RevID register, on SPI, 0xCE must be written to the 0x1F address to enable the extended register space, after which the RevID register is accessible at address 0x5. 0xCD must be written to the 0x1F address to disable the extended register space. On I2C, the RevID register is accessible at address 0x25. Create an interface config struct, and add a method for toggling the extended register space and a member for the RevId register address. Implement these for SPI. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com> Link: https://lore.kernel.org/r/20220605144659.4169853-4-demonsingur@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: max310x: use a separate regmap for each portCosmin Tanislav2022-06-101-32/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | The driver currently does manual register manipulation in multiple places to talk to a specific UART port. In order to talk to a specific UART port over SPI, the bits U1 and U0 of the register address can be set, as explained in the Command byte configuration section of the datasheet. Make this more elegant by creating regmaps for each UART port and setting the read_flag_mask and write_flag_mask accordingly. All communcations regarding global registers are done on UART port 0, so replace the global regmap entirely with the port 0 regmap. Also, remove the 0x1f masks from reg_writeable(), reg_volatile() and reg_precious() methods, since setting the U1 and U0 bits of the register address happens inside the regmap core now. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com> Link: https://lore.kernel.org/r/20220605144659.4169853-3-demonsingur@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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