static int sbsa_uart_probe(struct platform_device *pdev) { struct uart_amba_port *uap; struct resource *r; int portnr, ret; int baudrate; /* * Check the mandatory baud rate parameter in the DT node early * so that we can easily exit with the error. */ if (pdev->dev.of_node) { struct device_node *np = pdev->dev.of_node; ret = of_property_read_u32(np, "current-speed", &baudrate); if (ret) return ret; } else { baudrate = 115200; } portnr = pl011_find_free_port(); if (portnr < 0) return portnr; uap = devm_kzalloc(&pdev->dev, sizeof(struct uart_amba_port), GFP_KERNEL); if (!uap) return -ENOMEM; ret = platform_get_irq(pdev, 0); if (ret < 0) { if (ret != -EPROBE_DEFER) dev_err(&pdev->dev, "cannot obtain irq\n"); return ret; } uap->port.irq = ret; #ifdef CONFIG_ACPI_SPCR_TABLE if (qdf2400_e44_present) { dev_info(&pdev->dev, "working around QDF2400 SoC erratum 44\n"); uap->vendor = &vendor_qdt_qdf2400_e44; } else #endif uap->vendor = &vendor_sbsa; uap->reg_offset = uap->vendor->reg_offset; uap->fifosize = 32; uap->port.iotype = uap->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM; uap->port.ops = &sbsa_uart_pops; uap->fixed_baud = baudrate; snprintf(uap->type, sizeof(uap->type), "SBSA"); r = platform_get_resource(pdev, IORESOURCE_MEM, 0); ret = pl011_setup_port(&pdev->dev, uap, r, portnr); if (ret) return ret; platform_set_drvdata(pdev, uap); return pl011_register_port(uap); }linux内核uart驱动在设备注册时，使用acpi表定义的波特率来初始化串口，请根据我的要求和上述代码，在代码中添加这一功能

好的，根据你的要求，我可以在该函数中添加获取ACPI表中定义的波特率的功能，并使用该波特率来初始化串口。代码如下：

static int sbsa_uart_probe(struct platform_device *pdev) {
    struct uart_amba_port *uap;
    struct resource *r;
    int portnr, ret;
    int baudrate;
    struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);

    /* Check if ACPI companion device exists, and if so, read the current-speed property */
    if (adev) {
        struct acpi_device_node *adev_node = acpi_node_get_device_node(adev->handle);
        if (adev_node) {
            struct fwnode_handle *fwnode = &adev_node->fwnode;
            ret = fwnode_property_read_u32(fwnode, "current-speed", &baudrate);
            if (ret)
                return ret;
        }
    } else if (pdev->dev.of_node) {
        /* If there is no ACPI companion device, fall back to reading the current-speed property from DT node */
        struct device_node *np = pdev->dev.of_node;
        ret = of_property_read_u32(np, "current-speed", &baudrate);
        if (ret)
            return ret;
    } else {
        baudrate = 115200;
    }

    portnr = pl011_find_free_port();
    if (portnr < 0)
        return portnr;

    uap = devm_kzalloc(&pdev->dev, sizeof(struct uart_amba_port), GFP_KERNEL);
    if (!uap)
        return -ENOMEM;

    ret = platform_get_irq(pdev, 0);
    if (ret < 0) {
        if (ret != -EPROBE_DEFER)
            dev_err(&pdev->dev, "cannot obtain irq\n");
        return ret;
    }

    uap->port.irq    = ret;

#ifdef CONFIG_ACPI_SPCR_TABLE
    if (qdf2400_e44_present) {
        dev_info(&pdev->dev, "working around QDF2400 SoC erratum 44\n");
        uap->vendor = &vendor_qdt_qdf2400_e44;
    } else
#endif
        uap->vendor = &vendor_sbsa;

    uap->reg_offset = uap->vendor->reg_offset;
    uap->fifosize   = 32;
    uap->port.iotype = uap->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM;
    uap->port.ops   = &sbsa_uart_pops;
    uap->fixed_baud = baudrate;
    snprintf(uap->type, sizeof(uap->type), "SBSA");

    r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    ret = pl011_setup_port(&pdev->dev, uap, r, portnr);
    if (ret)
        return ret;

    platform_set_drvdata(pdev, uap);
    return pl011_register_port(uap);
}

我添加的代码在函数开头处，首先判断是否存在ACPI companion device，如果存在则从其属性中读取波特率，否则从DT node中读取。读取到的波特率将被用于初始化串口。