From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/tty/serial/8250/8250_aspeed_vuart.c | 607 ++++++++++++++++++++++++++++ 1 file changed, 607 insertions(+) create mode 100644 drivers/tty/serial/8250/8250_aspeed_vuart.c (limited to 'drivers/tty/serial/8250/8250_aspeed_vuart.c') diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c new file mode 100644 index 0000000000..4a9e71b2db --- /dev/null +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c @@ -0,0 +1,607 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Serial Port driver for Aspeed VUART device + * + * Copyright (C) 2016 Jeremy Kerr , IBM Corp. + * Copyright (C) 2006 Arnd Bergmann , IBM Corp. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "8250.h" + +#define ASPEED_VUART_GCRA 0x20 +#define ASPEED_VUART_GCRA_VUART_EN BIT(0) +#define ASPEED_VUART_GCRA_HOST_SIRQ_POLARITY BIT(1) +#define ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD BIT(5) +#define ASPEED_VUART_GCRB 0x24 +#define ASPEED_VUART_GCRB_HOST_SIRQ_MASK GENMASK(7, 4) +#define ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT 4 +#define ASPEED_VUART_ADDRL 0x28 +#define ASPEED_VUART_ADDRH 0x2c + +#define ASPEED_VUART_DEFAULT_LPC_ADDR 0x3f8 +#define ASPEED_VUART_DEFAULT_SIRQ 4 +#define ASPEED_VUART_DEFAULT_SIRQ_POLARITY IRQ_TYPE_LEVEL_LOW + +struct aspeed_vuart { + struct device *dev; + struct clk *clk; + int line; + struct timer_list unthrottle_timer; + struct uart_8250_port *port; +}; + +/* + * If we fill the tty flip buffers, we throttle the data ready interrupt + * to prevent dropped characters. This timeout defines how long we wait + * to (conditionally, depending on buffer state) unthrottle. + */ +static const int unthrottle_timeout = HZ/10; + +/* + * The VUART is basically two UART 'front ends' connected by their FIFO + * (no actual serial line in between). One is on the BMC side (management + * controller) and one is on the host CPU side. + * + * It allows the BMC to provide to the host a "UART" that pipes into + * the BMC itself and can then be turned by the BMC into a network console + * of some sort for example. + * + * This driver is for the BMC side. The sysfs files allow the BMC + * userspace which owns the system configuration policy, to specify + * at what IO port and interrupt number the host side will appear + * to the host on the Host <-> BMC LPC bus. It could be different on a + * different system (though most of them use 3f8/4). + */ + +static inline u8 aspeed_vuart_readb(struct aspeed_vuart *vuart, u8 reg) +{ + return readb(vuart->port->port.membase + reg); +} + +static inline void aspeed_vuart_writeb(struct aspeed_vuart *vuart, u8 val, u8 reg) +{ + writeb(val, vuart->port->port.membase + reg); +} + +static ssize_t lpc_address_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct aspeed_vuart *vuart = dev_get_drvdata(dev); + u16 addr; + + addr = (aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRH) << 8) | + (aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRL)); + + return sysfs_emit(buf, "0x%x\n", addr); +} + +static int aspeed_vuart_set_lpc_address(struct aspeed_vuart *vuart, u32 addr) +{ + if (addr > U16_MAX) + return -EINVAL; + + aspeed_vuart_writeb(vuart, addr >> 8, ASPEED_VUART_ADDRH); + aspeed_vuart_writeb(vuart, addr >> 0, ASPEED_VUART_ADDRL); + + return 0; +} + +static ssize_t lpc_address_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct aspeed_vuart *vuart = dev_get_drvdata(dev); + u32 val; + int err; + + err = kstrtou32(buf, 0, &val); + if (err) + return err; + + err = aspeed_vuart_set_lpc_address(vuart, val); + return err ? : count; +} + +static DEVICE_ATTR_RW(lpc_address); + +static ssize_t sirq_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct aspeed_vuart *vuart = dev_get_drvdata(dev); + u8 reg; + + reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRB); + reg &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK; + reg >>= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT; + + return sysfs_emit(buf, "%u\n", reg); +} + +static int aspeed_vuart_set_sirq(struct aspeed_vuart *vuart, u32 sirq) +{ + u8 reg; + + if (sirq > (ASPEED_VUART_GCRB_HOST_SIRQ_MASK >> ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT)) + return -EINVAL; + + sirq <<= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT; + sirq &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK; + + reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRB); + reg &= ~ASPEED_VUART_GCRB_HOST_SIRQ_MASK; + reg |= sirq; + aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRB); + + return 0; +} + +static ssize_t sirq_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct aspeed_vuart *vuart = dev_get_drvdata(dev); + unsigned long val; + int err; + + err = kstrtoul(buf, 0, &val); + if (err) + return err; + + err = aspeed_vuart_set_sirq(vuart, val); + return err ? : count; +} + +static DEVICE_ATTR_RW(sirq); + +static ssize_t sirq_polarity_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct aspeed_vuart *vuart = dev_get_drvdata(dev); + u8 reg; + + reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA); + reg &= ASPEED_VUART_GCRA_HOST_SIRQ_POLARITY; + + return sysfs_emit(buf, "%u\n", reg ? 1 : 0); +} + +static void aspeed_vuart_set_sirq_polarity(struct aspeed_vuart *vuart, + bool polarity) +{ + u8 reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA); + + if (polarity) + reg |= ASPEED_VUART_GCRA_HOST_SIRQ_POLARITY; + else + reg &= ~ASPEED_VUART_GCRA_HOST_SIRQ_POLARITY; + + aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA); +} + +static ssize_t sirq_polarity_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct aspeed_vuart *vuart = dev_get_drvdata(dev); + unsigned long val; + int err; + + err = kstrtoul(buf, 0, &val); + if (err) + return err; + + aspeed_vuart_set_sirq_polarity(vuart, val != 0); + + return count; +} + +static DEVICE_ATTR_RW(sirq_polarity); + +static struct attribute *aspeed_vuart_attrs[] = { + &dev_attr_sirq.attr, + &dev_attr_sirq_polarity.attr, + &dev_attr_lpc_address.attr, + NULL, +}; + +static const struct attribute_group aspeed_vuart_attr_group = { + .attrs = aspeed_vuart_attrs, +}; + +static void aspeed_vuart_set_enabled(struct aspeed_vuart *vuart, bool enabled) +{ + u8 reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA); + + if (enabled) + reg |= ASPEED_VUART_GCRA_VUART_EN; + else + reg &= ~ASPEED_VUART_GCRA_VUART_EN; + + aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA); +} + +static void aspeed_vuart_set_host_tx_discard(struct aspeed_vuart *vuart, + bool discard) +{ + u8 reg; + + reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA); + + /* If the DISABLE_HOST_TX_DISCARD bit is set, discard is disabled */ + if (!discard) + reg |= ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD; + else + reg &= ~ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD; + + aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA); +} + +static int aspeed_vuart_startup(struct uart_port *uart_port) +{ + struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port); + struct aspeed_vuart *vuart = uart_8250_port->port.private_data; + int rc; + + rc = serial8250_do_startup(uart_port); + if (rc) + return rc; + + aspeed_vuart_set_host_tx_discard(vuart, false); + + return 0; +} + +static void aspeed_vuart_shutdown(struct uart_port *uart_port) +{ + struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port); + struct aspeed_vuart *vuart = uart_8250_port->port.private_data; + + aspeed_vuart_set_host_tx_discard(vuart, true); + + serial8250_do_shutdown(uart_port); +} + +static void __aspeed_vuart_set_throttle(struct uart_8250_port *up, + bool throttle) +{ + unsigned char irqs = UART_IER_RLSI | UART_IER_RDI; + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&up->port.lock); + + up->ier &= ~irqs; + if (!throttle) + up->ier |= irqs; + serial_out(up, UART_IER, up->ier); +} +static void aspeed_vuart_set_throttle(struct uart_port *port, bool throttle) +{ + struct uart_8250_port *up = up_to_u8250p(port); + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + __aspeed_vuart_set_throttle(up, throttle); + spin_unlock_irqrestore(&port->lock, flags); +} + +static void aspeed_vuart_throttle(struct uart_port *port) +{ + aspeed_vuart_set_throttle(port, true); +} + +static void aspeed_vuart_unthrottle(struct uart_port *port) +{ + aspeed_vuart_set_throttle(port, false); +} + +static void aspeed_vuart_unthrottle_exp(struct timer_list *timer) +{ + struct aspeed_vuart *vuart = from_timer(vuart, timer, unthrottle_timer); + struct uart_8250_port *up = vuart->port; + + if (!tty_buffer_space_avail(&up->port.state->port)) { + mod_timer(&vuart->unthrottle_timer, + jiffies + unthrottle_timeout); + return; + } + + aspeed_vuart_unthrottle(&up->port); +} + +/* + * Custom interrupt handler to manage finer-grained flow control. Although we + * have throttle/unthrottle callbacks, we've seen that the VUART device can + * deliver characters faster than the ldisc has a chance to check buffer space + * against the throttle threshold. This results in dropped characters before + * the throttle. + * + * We do this by checking for flip buffer space before RX. If we have no space, + * throttle now and schedule an unthrottle for later, once the ldisc has had + * a chance to drain the buffers. + */ +static int aspeed_vuart_handle_irq(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + unsigned int iir, lsr; + unsigned long flags; + unsigned int space, count; + + iir = serial_port_in(port, UART_IIR); + + if (iir & UART_IIR_NO_INT) + return 0; + + spin_lock_irqsave(&port->lock, flags); + + lsr = serial_port_in(port, UART_LSR); + + if (lsr & (UART_LSR_DR | UART_LSR_BI)) { + space = tty_buffer_space_avail(&port->state->port); + + if (!space) { + /* throttle and schedule an unthrottle later */ + struct aspeed_vuart *vuart = port->private_data; + __aspeed_vuart_set_throttle(up, true); + + if (!timer_pending(&vuart->unthrottle_timer)) + mod_timer(&vuart->unthrottle_timer, + jiffies + unthrottle_timeout); + + } else { + count = min(space, 256U); + + do { + serial8250_read_char(up, lsr); + lsr = serial_in(up, UART_LSR); + if (--count == 0) + break; + } while (lsr & (UART_LSR_DR | UART_LSR_BI)); + + tty_flip_buffer_push(&port->state->port); + } + } + + serial8250_modem_status(up); + if (lsr & UART_LSR_THRE) + serial8250_tx_chars(up); + + uart_unlock_and_check_sysrq_irqrestore(port, flags); + + return 1; +} + +static void aspeed_vuart_auto_configure_sirq_polarity( + struct aspeed_vuart *vuart, struct device_node *syscon_np, + u32 reg_offset, u32 reg_mask) +{ + struct regmap *regmap; + u32 value; + + regmap = syscon_node_to_regmap(syscon_np); + if (IS_ERR(regmap)) { + dev_warn(vuart->dev, + "could not get regmap for aspeed,sirq-polarity-sense\n"); + return; + } + if (regmap_read(regmap, reg_offset, &value)) { + dev_warn(vuart->dev, "could not read hw strap table\n"); + return; + } + + aspeed_vuart_set_sirq_polarity(vuart, (value & reg_mask) == 0); +} + +static int aspeed_vuart_map_irq_polarity(u32 dt) +{ + switch (dt) { + case IRQ_TYPE_LEVEL_LOW: + return 0; + case IRQ_TYPE_LEVEL_HIGH: + return 1; + default: + return -EINVAL; + } +} + +static int aspeed_vuart_probe(struct platform_device *pdev) +{ + struct of_phandle_args sirq_polarity_sense_args; + struct uart_8250_port port; + struct aspeed_vuart *vuart; + struct device_node *np; + struct resource *res; + u32 clk, prop, sirq[2]; + int rc, sirq_polarity; + + np = pdev->dev.of_node; + + vuart = devm_kzalloc(&pdev->dev, sizeof(*vuart), GFP_KERNEL); + if (!vuart) + return -ENOMEM; + + vuart->dev = &pdev->dev; + timer_setup(&vuart->unthrottle_timer, aspeed_vuart_unthrottle_exp, 0); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -EINVAL; + + memset(&port, 0, sizeof(port)); + port.port.private_data = vuart; + port.port.mapbase = res->start; + port.port.mapsize = resource_size(res); + port.port.startup = aspeed_vuart_startup; + port.port.shutdown = aspeed_vuart_shutdown; + port.port.throttle = aspeed_vuart_throttle; + port.port.unthrottle = aspeed_vuart_unthrottle; + port.port.status = UPSTAT_SYNC_FIFO; + port.port.dev = &pdev->dev; + port.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); + port.bugs |= UART_BUG_TXRACE; + + rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group); + if (rc < 0) + return rc; + + if (of_property_read_u32(np, "clock-frequency", &clk)) { + vuart->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(vuart->clk)) { + dev_warn(&pdev->dev, + "clk or clock-frequency not defined\n"); + rc = PTR_ERR(vuart->clk); + goto err_sysfs_remove; + } + + rc = clk_prepare_enable(vuart->clk); + if (rc < 0) + goto err_sysfs_remove; + + clk = clk_get_rate(vuart->clk); + } + + /* If current-speed was set, then try not to change it. */ + if (of_property_read_u32(np, "current-speed", &prop) == 0) + port.port.custom_divisor = clk / (16 * prop); + + /* Check for shifted address mapping */ + if (of_property_read_u32(np, "reg-offset", &prop) == 0) + port.port.mapbase += prop; + + /* Check for registers offset within the devices address range */ + if (of_property_read_u32(np, "reg-shift", &prop) == 0) + port.port.regshift = prop; + + /* Check for fifo size */ + if (of_property_read_u32(np, "fifo-size", &prop) == 0) + port.port.fifosize = prop; + + /* Check for a fixed line number */ + rc = of_alias_get_id(np, "serial"); + if (rc >= 0) + port.port.line = rc; + + port.port.irq = irq_of_parse_and_map(np, 0); + port.port.handle_irq = aspeed_vuart_handle_irq; + port.port.iotype = UPIO_MEM; + port.port.type = PORT_ASPEED_VUART; + port.port.uartclk = clk; + port.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP + | UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_NO_THRE_TEST; + + if (of_property_read_bool(np, "no-loopback-test")) + port.port.flags |= UPF_SKIP_TEST; + + if (port.port.fifosize) + port.capabilities = UART_CAP_FIFO; + + if (of_property_read_bool(np, "auto-flow-control")) + port.capabilities |= UART_CAP_AFE; + + rc = serial8250_register_8250_port(&port); + if (rc < 0) + goto err_clk_disable; + + vuart->line = rc; + vuart->port = serial8250_get_port(vuart->line); + + rc = of_parse_phandle_with_fixed_args( + np, "aspeed,sirq-polarity-sense", 2, 0, + &sirq_polarity_sense_args); + if (rc < 0) { + dev_dbg(&pdev->dev, + "aspeed,sirq-polarity-sense property not found\n"); + } else { + aspeed_vuart_auto_configure_sirq_polarity( + vuart, sirq_polarity_sense_args.np, + sirq_polarity_sense_args.args[0], + BIT(sirq_polarity_sense_args.args[1])); + of_node_put(sirq_polarity_sense_args.np); + } + + rc = of_property_read_u32(np, "aspeed,lpc-io-reg", &prop); + if (rc < 0) + prop = ASPEED_VUART_DEFAULT_LPC_ADDR; + + rc = aspeed_vuart_set_lpc_address(vuart, prop); + if (rc < 0) { + dev_err(&pdev->dev, "invalid value in aspeed,lpc-io-reg property\n"); + goto err_clk_disable; + } + + rc = of_property_read_u32_array(np, "aspeed,lpc-interrupts", sirq, 2); + if (rc < 0) { + sirq[0] = ASPEED_VUART_DEFAULT_SIRQ; + sirq[1] = ASPEED_VUART_DEFAULT_SIRQ_POLARITY; + } + + rc = aspeed_vuart_set_sirq(vuart, sirq[0]); + if (rc < 0) { + dev_err(&pdev->dev, "invalid sirq number in aspeed,lpc-interrupts property\n"); + goto err_clk_disable; + } + + sirq_polarity = aspeed_vuart_map_irq_polarity(sirq[1]); + if (sirq_polarity < 0) { + dev_err(&pdev->dev, "invalid sirq polarity in aspeed,lpc-interrupts property\n"); + rc = sirq_polarity; + goto err_clk_disable; + } + + aspeed_vuart_set_sirq_polarity(vuart, sirq_polarity); + + aspeed_vuart_set_enabled(vuart, true); + aspeed_vuart_set_host_tx_discard(vuart, true); + platform_set_drvdata(pdev, vuart); + + return 0; + +err_clk_disable: + clk_disable_unprepare(vuart->clk); + irq_dispose_mapping(port.port.irq); +err_sysfs_remove: + sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group); + return rc; +} + +static int aspeed_vuart_remove(struct platform_device *pdev) +{ + struct aspeed_vuart *vuart = platform_get_drvdata(pdev); + + del_timer_sync(&vuart->unthrottle_timer); + aspeed_vuart_set_enabled(vuart, false); + serial8250_unregister_port(vuart->line); + sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group); + clk_disable_unprepare(vuart->clk); + + return 0; +} + +static const struct of_device_id aspeed_vuart_table[] = { + { .compatible = "aspeed,ast2400-vuart" }, + { .compatible = "aspeed,ast2500-vuart" }, + { }, +}; + +static struct platform_driver aspeed_vuart_driver = { + .driver = { + .name = "aspeed-vuart", + .of_match_table = aspeed_vuart_table, + }, + .probe = aspeed_vuart_probe, + .remove = aspeed_vuart_remove, +}; + +module_platform_driver(aspeed_vuart_driver); + +MODULE_AUTHOR("Jeremy Kerr "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Driver for Aspeed VUART device"); -- cgit v1.2.3