drivers/tty/serial/8250/8250_ni.c:277:12: warning: stack frame size (1072) exceeds limit (1024) in 'ni16550_probe'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   b4911fb0b060899e4eebca0151eb56deb86921ec
commit: 3d5390f4dbe633472b2a4824e66ca5c4eac6fb19 serial: 8250: add driver for NI UARTs
date:   3 months ago
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20250703/202507030557.vIewJJQO-lkp@xxxxxxxxx/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250703/202507030557.vIewJJQO-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507030557.vIewJJQO-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> drivers/tty/serial/8250/8250_ni.c:277:12: warning: stack frame size (1072) exceeds limit (1024) in 'ni16550_probe' [-Wframe-larger-than]
     277 | static int ni16550_probe(struct platform_device *pdev)
         |            ^
   1 warning generated.


vim +/ni16550_probe +277 drivers/tty/serial/8250/8250_ni.c

   276	
 > 277	static int ni16550_probe(struct platform_device *pdev)
   278	{
   279		const struct ni16550_device_info *info;
   280		struct device *dev = &pdev->dev;
   281		struct uart_8250_port uart = {};
   282		unsigned int txfifosz, rxfifosz;
   283		unsigned int prescaler = 0;
   284		struct ni16550_data *data;
   285		const char *portmode;
   286		bool rs232_property;
   287		int ret;
   288		int irq;
   289	
   290		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
   291		if (!data)
   292			return -ENOMEM;
   293	
   294		spin_lock_init(&uart.port.lock);
   295	
   296		irq = platform_get_irq(pdev, 0);
   297		if (irq < 0)
   298			return irq;
   299	
   300		ret = ni16550_get_regs(pdev, &uart.port);
   301		if (ret < 0)
   302			return ret;
   303	
   304		/* early setup so that serial_in()/serial_out() work */
   305		serial8250_set_defaults(&uart);
   306	
   307		info = device_get_match_data(dev);
   308	
   309		uart.port.dev		= dev;
   310		uart.port.irq		= irq;
   311		uart.port.irqflags	= IRQF_SHARED;
   312		uart.port.flags		= UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF
   313						| UPF_FIXED_PORT | UPF_FIXED_TYPE;
   314		uart.port.startup	= ni16550_port_startup;
   315		uart.port.shutdown	= ni16550_port_shutdown;
   316	
   317		/*
   318		 * Hardware instantiation of FIFO sizes are held in registers.
   319		 */
   320		txfifosz = ni16550_read_fifo_size(&uart, NI16550_TFS_OFFSET);
   321		rxfifosz = ni16550_read_fifo_size(&uart, NI16550_RFS_OFFSET);
   322	
   323		dev_dbg(dev, "NI 16550 has TX FIFO size %u, RX FIFO size %u\n",
   324			txfifosz, rxfifosz);
   325	
   326		uart.port.type		= PORT_16550A;
   327		uart.port.fifosize	= txfifosz;
   328		uart.tx_loadsz		= txfifosz;
   329		uart.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10;
   330		uart.capabilities	= UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR;
   331	
   332		/*
   333		 * Declaration of the base clock frequency can come from one of:
   334		 * - static declaration in this driver (for older ACPI IDs)
   335		 * - a "clock-frquency" ACPI
   336		 */
   337		if (info->uartclk)
   338			uart.port.uartclk = info->uartclk;
   339		if (device_property_read_u32(dev, "clock-frequency",
   340					     &uart.port.uartclk)) {
   341			data->clk = devm_clk_get_enabled(dev, NULL);
   342			if (!IS_ERR(data->clk))
   343				uart.port.uartclk = clk_get_rate(data->clk);
   344		}
   345	
   346		if (!uart.port.uartclk) {
   347			dev_err(dev, "unable to determine clock frequency!\n");
   348			ret = -ENODEV;
   349			goto err;
   350		}
   351	
   352		if (info->prescaler)
   353			prescaler = info->prescaler;
   354		device_property_read_u32(dev, "clock-prescaler", &prescaler);
   355	
   356		if (prescaler != 0) {
   357			uart.port.set_mctrl = ni16550_set_mctrl;
   358			ni16550_config_prescaler(&uart, (u8)prescaler);
   359		}
   360	
   361		/*
   362		 * The determination of whether or not this is an RS-485 or RS-232 port
   363		 * can come from the PMR (if present), otherwise we're solely an RS-485
   364		 * port.
   365		 *
   366		 * This is a device-specific property, and there are old devices in the
   367		 * field using "transceiver" as an ACPI property, so we have to check
   368		 * for that as well.
   369		 */
   370		if (!device_property_read_string(dev, "transceiver", &portmode)) {
   371			rs232_property = strncmp(portmode, "RS-232", 6) == 0;
   372	
   373			dev_dbg(dev, "port is in %s mode (via device property)\n",
   374				rs232_property ? "RS-232" : "RS-485");
   375		} else if (info->flags & NI_HAS_PMR) {
   376			rs232_property = is_pmr_rs232_mode(&uart);
   377	
   378			dev_dbg(dev, "port is in %s mode (via PMR)\n",
   379				rs232_property ? "RS-232" : "RS-485");
   380		} else {
   381			rs232_property = 0;
   382	
   383			dev_dbg(dev, "port is fixed as RS-485\n");
   384		}
   385	
   386		if (!rs232_property) {
   387			/*
   388			 * Neither the 'transceiver' property nor the PMR indicate
   389			 * that this is an RS-232 port, so it must be an RS-485 one.
   390			 */
   391			ni16550_rs485_setup(&uart.port);
   392		}
   393	
   394		ret = serial8250_register_8250_port(&uart);
   395		if (ret < 0)
   396			goto err;
   397		data->line = ret;
   398	
   399		platform_set_drvdata(pdev, data);
   400		return 0;
   401	
   402	err:
   403		return ret;
   404	}
   405	

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