Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 607 insertions, 0 deletions

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 <jk@ozlabs.org>, IBM Corp.
+ *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
+ */
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/clk.h>
+
+#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 <jk@ozlabs.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Driver for Aspeed VUART device");