1 files changed, 132 insertions, 0 deletions
diff --git a/arch/x86/kernel/io_delay.c b/arch/x86/kernel/io_delay.c
new file mode 100644
index 000000000..805b7a341
--- /dev/null
+++ b/arch/x86/kernel/io_delay.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * I/O delay strategies for inb_p/outb_p
+ *
+ * Allow for a DMI based override of port 0x80, needed for certain HP laptops
+ * and possibly other systems. Also allow for the gradual elimination of
+ * outb_p/inb_p API uses.
+ */
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/dmi.h>
+#include <linux/io.h>
+
+int io_delay_type __read_mostly = CONFIG_DEFAULT_IO_DELAY_TYPE;
+
+static int __initdata io_delay_override;
+
+/*
+ * Paravirt wants native_io_delay to be a constant.
+ */
+void native_io_delay(void)
+{
+	switch (io_delay_type) {
+	default:
+	case CONFIG_IO_DELAY_TYPE_0X80:
+		asm volatile ("outb %al, $0x80");
+		break;
+	case CONFIG_IO_DELAY_TYPE_0XED:
+		asm volatile ("outb %al, $0xed");
+		break;
+	case CONFIG_IO_DELAY_TYPE_UDELAY:
+		/*
+		 * 2 usecs is an upper-bound for the outb delay but
+		 * note that udelay doesn't have the bus-level
+		 * side-effects that outb does, nor does udelay() have
+		 * precise timings during very early bootup (the delays
+		 * are shorter until calibrated):
+		 */
+		udelay(2);
+	case CONFIG_IO_DELAY_TYPE_NONE:
+		break;
+	}
+}
+EXPORT_SYMBOL(native_io_delay);
+
+static int __init dmi_io_delay_0xed_port(const struct dmi_system_id *id)
+{
+	if (io_delay_type == CONFIG_IO_DELAY_TYPE_0X80) {
+		pr_notice("%s: using 0xed I/O delay port\n", id->ident);
+		io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
+	}
+
+	return 0;
+}
+
+/*
+ * Quirk table for systems that misbehave (lock up, etc.) if port
+ * 0x80 is used:
+ */
+static const struct dmi_system_id io_delay_0xed_port_dmi_table[] __initconst = {
+	{
+		.callback	= dmi_io_delay_0xed_port,
+		.ident		= "Compaq Presario V6000",
+		.matches	= {
+			DMI_MATCH(DMI_BOARD_VENDOR,	"Quanta"),
+			DMI_MATCH(DMI_BOARD_NAME,	"30B7")
+		}
+	},
+	{
+		.callback	= dmi_io_delay_0xed_port,
+		.ident		= "HP Pavilion dv9000z",
+		.matches	= {
+			DMI_MATCH(DMI_BOARD_VENDOR,	"Quanta"),
+			DMI_MATCH(DMI_BOARD_NAME,	"30B9")
+		}
+	},
+	{
+		.callback	= dmi_io_delay_0xed_port,
+		.ident		= "HP Pavilion dv6000",
+		.matches	= {
+			DMI_MATCH(DMI_BOARD_VENDOR,	"Quanta"),
+			DMI_MATCH(DMI_BOARD_NAME,	"30B8")
+		}
+	},
+	{
+		.callback	= dmi_io_delay_0xed_port,
+		.ident		= "HP Pavilion tx1000",
+		.matches	= {
+			DMI_MATCH(DMI_BOARD_VENDOR,	"Quanta"),
+			DMI_MATCH(DMI_BOARD_NAME,	"30BF")
+		}
+	},
+	{
+		.callback	= dmi_io_delay_0xed_port,
+		.ident		= "Presario F700",
+		.matches	= {
+			DMI_MATCH(DMI_BOARD_VENDOR,	"Quanta"),
+			DMI_MATCH(DMI_BOARD_NAME,	"30D3")
+		}
+	},
+	{ }
+};
+
+void __init io_delay_init(void)
+{
+	if (!io_delay_override)
+		dmi_check_system(io_delay_0xed_port_dmi_table);
+}
+
+static int __init io_delay_param(char *s)
+{
+	if (!s)
+		return -EINVAL;
+
+	if (!strcmp(s, "0x80"))
+		io_delay_type = CONFIG_IO_DELAY_TYPE_0X80;
+	else if (!strcmp(s, "0xed"))
+		io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
+	else if (!strcmp(s, "udelay"))
+		io_delay_type = CONFIG_IO_DELAY_TYPE_UDELAY;
+	else if (!strcmp(s, "none"))
+		io_delay_type = CONFIG_IO_DELAY_TYPE_NONE;
+	else
+		return -EINVAL;
+
+	io_delay_override = 1;
+	return 0;
+}
+
+early_param("io_delay", io_delay_param);