kernel/linux.git/drivers/tty/serial/xilinx_uartps.c, branch v7.0-rc1

serial: xilinx_uartps: fix rs485 delay_rts_after_send

2025-12-23T10:55:16+00:00

RTS line control with delay should be triggered when there is no more bytes in kfifo and hardware buffer is empty. Without this patch RTS control is scheduled right after feeding hardware buffer and this is too early. RTS line may change state before hardware buffer is empty. With this patch delayed RTS state change is triggered when function cdns_uart_handle_tx is called from cdns_uart_isr on CDNS_UART_IXR_TXEMPTY exactly when hardware completed transmission Fixes: fccc9d9233f9 ("tty: serial: uartps: Add rs485 support to uartps driver") Cc: stable Link: https://patch.msgid.link/20251221103221.1971125-1-jakub.turek@elsta.tech Signed-off-by: Jakub Turek Signed-off-by: Greg Kroah-Hartman

serial: xilinx_uartps: drop cdns_uart::cdns_uart_driver

2025-11-21T17:31:27+00:00

Provided the uart driver is available globally, there is no need to store a pointer to it in struct cdns_uart. Instead, use the global cdns_uart_uart_driver in the code directly. Signed-off-by: Jiri Slaby (SUSE) Acked-by: Michal Simek Link: https://patch.msgid.link/20251119092457.826789-3-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: xilinx_uartps: read reg size from DTS

2025-09-06T13:51:47+00:00

Current implementation uses `CDNS_UART_REGISTER_SPACE(0x1000)` for request_mem_region() and ioremap() in cdns_uart_request_port() API. The cadence/xilinx IP has register space defined from offset 0x0 to 0x48. It also mentions that the register map is defined as [6:0]. So, the upper region may/maynot be used based on the IP integration. In Axiado AX3000 SoC two UART instances are defined 0x100 apart. That is creating issue in some other instance due to overlap with addresses. Since, this address space is already being defined in the devicetree, use the same when requesting the register space. Fixes: 1f7055779001 ("arm64: dts: axiado: Add initial support for AX3000 SoC and eval board") Acked-by: Michal Simek Signed-off-by: Harshit Shah Link: https://lore.kernel.org/r/20250902-xilinx-uartps-reg-size-v3-1-d11cfa7258e3@axiado.com Signed-off-by: Greg Kroah-Hartman

serial: xilinx_uartps: Use helper function hrtimer_update_function()

2025-02-18T16:41:35+00:00

The field 'function' of struct hrtimer should not be changed directly, as the write is lockless and a concurrent timer expiry might end up using the wrong function pointer. Switch to use hrtimer_update_function() which also performs runtime checks that it is safe to modify the callback. Signed-off-by: Nam Cao Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/af7823518fb060c6c97105a2513cfc61adbdf38f.1738746927.git.namcao@linutronix.de

serial: xilinx_uartps: Switch to use hrtimer_setup()

2025-02-18T10:19:03+00:00

hrtimer_setup() takes the callback function pointer as argument and initializes the timer completely. Replace hrtimer_init() and the open coded initialization of hrtimer::function with the new setup mechanism. Patch was created by using Coccinelle. Signed-off-by: Nam Cao Signed-off-by: Thomas Gleixner Acked-by: Zack Rusin Link: https://lore.kernel.org/all/4a028a23126b3350a5e243dcb49e1ef1b2a4b740.1738746904.git.namcao@linutronix.de

tty: xilinx_uartps: split sysrq handling

2025-01-13T05:46:50+00:00

lockdep detects the following circular locking dependency: CPU 0 CPU 1 ========================== ============================ cdns_uart_isr() printk() uart_port_lock(port) console_lock() cdns_uart_console_write() if (!port->sysrq) uart_port_lock(port) uart_handle_break() port->sysrq = ... uart_handle_sysrq_char() printk() console_lock() The fixed commit attempts to avoid this situation by only taking the port lock in cdns_uart_console_write if port->sysrq unset. However, if (as shown above) cdns_uart_console_write runs before port->sysrq is set, then it will try to take the port lock anyway. This may result in a deadlock. Fix this by splitting sysrq handling into two parts. We use the prepare helper under the port lock and defer handling until we release the lock. Fixes: 74ea66d4ca06 ("tty: xuartps: Improve sysrq handling") Signed-off-by: Sean Anderson Cc: stable@vger.kernel.org # c980248179d: serial: xilinx_uartps: Use port lock wrappers Acked-by: John Ogness Link: https://lore.kernel.org/r/20250110213822.2107462-1-sean.anderson@linux.dev Signed-off-by: Greg Kroah-Hartman

serial: Switch back to struct platform_driver::remove()

2024-10-11T06:13:28+00:00

After commit 0edb555a65d1 ("platform: Make platform_driver::remove() return void") .remove() is (again) the right callback to implement for platform drivers. Convert all platform drivers below drivers/tty/serial to use .remove(), with the eventual goal to drop struct platform_driver::remove_new(). As .remove() and .remove_new() have the same prototypes, conversion is done by just changing the structure member name in the driver initializer. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20241007205803.444994-7-u.kleine-koenig@baylibre.com Signed-off-by: Greg Kroah-Hartman

serial: xilinx_uartps: Make cdns_rs485_supported static

2024-09-03T08:46:58+00:00

The sparse tool complains as follows: drivers/tty/serial/xilinx_uartps.c:222:21: warning: symbol 'cdns_rs485_supported' was not declared. Should it be static? This symbol is not used outside xilinx_uartps.c, so marks it static. Signed-off-by: Jinjie Ruan Link: https://lore.kernel.org/r/20240819120107.3884973-1-ruanjinjie@huawei.com Signed-off-by: Greg Kroah-Hartman

tty: serial: uartps: Add support for uartps controller reset

2024-05-04T16:11:05+00:00

Add support for an optional reset for the uartps controller using the reset driver. If the uartps node contains the "resets" property, then cdns_uart_startup performs uartps controller non-pulse out of reset and reset in exit path. Signed-off-by: Manikanta Guntupalli Link: https://lore.kernel.org/r/20240425062358.1347684-4-manikanta.guntupalli@amd.com Signed-off-by: Greg Kroah-Hartman

tty: serial: switch from circ_buf to kfifo

2024-04-09T13:28:03+00:00

Switch from struct circ_buf to proper kfifo. kfifo provides much better API, esp. when wrap-around of the buffer needs to be taken into account. Look at pl011_dma_tx_refill() or cpm_uart_tx_pump() changes for example. Kfifo API can also fill in scatter-gather DMA structures, so it easier for that use case too. Look at lpuart_dma_tx() for example. Note that not all drivers can be converted to that (like atmel_serial), they handle DMA specially. Note that usb-serial uses kfifo for TX for ages. omap needed a bit more care as it needs to put a char into FIFO to start the DMA transfer when OMAP_DMA_TX_KICK is set. In that case, we have to do kfifo_dma_out_prepare twice: once to find out the tx_size (to find out if it is worths to do DMA at all -- size >= 4), the second time for the actual transfer. All traces of circ_buf are removed from serial_core.h (and its struct uart_state). Signed-off-by: Jiri Slaby (SUSE) Cc: Al Cooper Cc: Matthias Brugger Cc: AngeloGioacchino Del Regno Cc: Kumaravel Thiagarajan Cc: Tharun Kumar P Cc: Russell King Cc: Vineet Gupta Cc: Richard Genoud Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: Alexander Shiyan Cc: Baruch Siach Cc: Maciej W. Rozycki Cc: Shawn Guo Cc: Sascha Hauer Cc: Fabio Estevam Cc: Neil Armstrong Cc: Kevin Hilman Cc: Jerome Brunet Cc: Martin Blumenstingl Cc: Taichi Sugaya Cc: Takao Orito Cc: Bjorn Andersson Cc: Konrad Dybcio Cc: Pali Rohár Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Aneesh Kumar K.V Cc: Naveen N. Rao Cc: Manivannan Sadhasivam Cc: Krzysztof Kozlowski Cc: Alim Akhtar Cc: Laxman Dewangan Cc: Thierry Reding Cc: Jonathan Hunter Cc: Orson Zhai Cc: Baolin Wang Cc: Chunyan Zhang Cc: Patrice Chotard Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: David S. Miller Cc: Hammer Hsieh Cc: Peter Korsgaard Cc: Timur Tabi Cc: Michal Simek Cc: Sumit Semwal Cc: Christian König Link: https://lore.kernel.org/r/20240405060826.2521-13-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman