forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
175 lines
4.5 KiB
175 lines
4.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Freescale 16550 UART "driver", Copyright (C) 2011 Paul Gortmaker. |
|
* Copyright 2020 NXP |
|
* Copyright 2020 Puresoftware Ltd. |
|
* |
|
* This isn't a full driver; it just provides an alternate IRQ |
|
* handler to deal with an errata and provide ACPI wrapper. |
|
* Everything else is just using the bog standard 8250 support. |
|
* |
|
* We follow code flow of serial8250_default_handle_irq() but add |
|
* a check for a break and insert a dummy read on the Rx for the |
|
* immediately following IRQ event. |
|
* |
|
* We re-use the already existing "bug handling" lsr_saved_flags |
|
* field to carry the "what we just did" information from the one |
|
* IRQ event to the next one. |
|
*/ |
|
|
|
#include <linux/acpi.h> |
|
#include <linux/serial_reg.h> |
|
#include <linux/serial_8250.h> |
|
|
|
#include "8250.h" |
|
|
|
struct fsl8250_data { |
|
int line; |
|
}; |
|
|
|
int fsl8250_handle_irq(struct uart_port *port) |
|
{ |
|
unsigned char lsr, orig_lsr; |
|
unsigned long flags; |
|
unsigned int iir; |
|
struct uart_8250_port *up = up_to_u8250p(port); |
|
|
|
spin_lock_irqsave(&up->port.lock, flags); |
|
|
|
iir = port->serial_in(port, UART_IIR); |
|
if (iir & UART_IIR_NO_INT) { |
|
spin_unlock_irqrestore(&up->port.lock, flags); |
|
return 0; |
|
} |
|
|
|
/* This is the WAR; if last event was BRK, then read and return */ |
|
if (unlikely(up->lsr_saved_flags & UART_LSR_BI)) { |
|
up->lsr_saved_flags &= ~UART_LSR_BI; |
|
port->serial_in(port, UART_RX); |
|
spin_unlock_irqrestore(&up->port.lock, flags); |
|
return 1; |
|
} |
|
|
|
lsr = orig_lsr = up->port.serial_in(&up->port, UART_LSR); |
|
|
|
/* Process incoming characters first */ |
|
if ((lsr & (UART_LSR_DR | UART_LSR_BI)) && |
|
(up->ier & (UART_IER_RLSI | UART_IER_RDI))) { |
|
lsr = serial8250_rx_chars(up, lsr); |
|
} |
|
|
|
/* Stop processing interrupts on input overrun */ |
|
if ((orig_lsr & UART_LSR_OE) && (up->overrun_backoff_time_ms > 0)) { |
|
unsigned long delay; |
|
|
|
up->ier = port->serial_in(port, UART_IER); |
|
if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) { |
|
port->ops->stop_rx(port); |
|
} else { |
|
/* Keep restarting the timer until |
|
* the input overrun subsides. |
|
*/ |
|
cancel_delayed_work(&up->overrun_backoff); |
|
} |
|
|
|
delay = msecs_to_jiffies(up->overrun_backoff_time_ms); |
|
schedule_delayed_work(&up->overrun_backoff, delay); |
|
} |
|
|
|
serial8250_modem_status(up); |
|
|
|
if ((lsr & UART_LSR_THRE) && (up->ier & UART_IER_THRI)) |
|
serial8250_tx_chars(up); |
|
|
|
up->lsr_saved_flags = orig_lsr; |
|
uart_unlock_and_check_sysrq(&up->port, flags); |
|
return 1; |
|
} |
|
EXPORT_SYMBOL_GPL(fsl8250_handle_irq); |
|
|
|
#ifdef CONFIG_ACPI |
|
static int fsl8250_acpi_probe(struct platform_device *pdev) |
|
{ |
|
struct fsl8250_data *data; |
|
struct uart_8250_port port8250; |
|
struct device *dev = &pdev->dev; |
|
struct resource *regs; |
|
|
|
int ret, irq; |
|
|
|
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
|
if (!regs) { |
|
dev_err(dev, "no registers defined\n"); |
|
return -EINVAL; |
|
} |
|
|
|
irq = platform_get_irq(pdev, 0); |
|
if (irq < 0) { |
|
if (irq != -EPROBE_DEFER) |
|
dev_err(dev, "cannot get irq\n"); |
|
return irq; |
|
} |
|
|
|
memset(&port8250, 0, sizeof(port8250)); |
|
|
|
ret = device_property_read_u32(dev, "clock-frequency", |
|
&port8250.port.uartclk); |
|
if (ret) |
|
return ret; |
|
|
|
spin_lock_init(&port8250.port.lock); |
|
|
|
port8250.port.mapbase = regs->start; |
|
port8250.port.irq = irq; |
|
port8250.port.handle_irq = fsl8250_handle_irq; |
|
port8250.port.type = PORT_16550A; |
|
port8250.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF |
|
| UPF_FIXED_PORT | UPF_IOREMAP |
|
| UPF_FIXED_TYPE; |
|
port8250.port.dev = dev; |
|
port8250.port.mapsize = resource_size(regs); |
|
port8250.port.iotype = UPIO_MEM; |
|
port8250.port.irqflags = IRQF_SHARED; |
|
|
|
port8250.port.membase = devm_ioremap(dev, port8250.port.mapbase, |
|
port8250.port.mapsize); |
|
if (!port8250.port.membase) |
|
return -ENOMEM; |
|
|
|
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
|
if (!data) |
|
return -ENOMEM; |
|
|
|
data->line = serial8250_register_8250_port(&port8250); |
|
if (data->line < 0) |
|
return data->line; |
|
|
|
platform_set_drvdata(pdev, data); |
|
return 0; |
|
} |
|
|
|
static int fsl8250_acpi_remove(struct platform_device *pdev) |
|
{ |
|
struct fsl8250_data *data = platform_get_drvdata(pdev); |
|
|
|
serial8250_unregister_port(data->line); |
|
return 0; |
|
} |
|
|
|
static const struct acpi_device_id fsl_8250_acpi_id[] = { |
|
{ "NXP0018", 0 }, |
|
{ }, |
|
}; |
|
MODULE_DEVICE_TABLE(acpi, fsl_8250_acpi_id); |
|
|
|
static struct platform_driver fsl8250_platform_driver = { |
|
.driver = { |
|
.name = "fsl-16550-uart", |
|
.acpi_match_table = ACPI_PTR(fsl_8250_acpi_id), |
|
}, |
|
.probe = fsl8250_acpi_probe, |
|
.remove = fsl8250_acpi_remove, |
|
}; |
|
|
|
module_platform_driver(fsl8250_platform_driver); |
|
#endif
|
|
|