x86: Add a simple superio driver for SMSC LPC47M

On most x86 boards, the legacy serial ports (io address 0x3f8/0x2f8)
are provided by a superio chip connected to the LPC bus. We must
program the superio chip so that serial ports are available for us.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/x86/include/asm/pnp_def.h

+/*
+ * Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * Adapted from coreboot src/include/device/pnp_def.h
+ * and arch/x86/include/arch/io.h
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _ASM_PNP_DEF_H_
+#define _ASM_PNP_DEF_H_
+
+#include <asm/io.h>
+
+#define PNP_IDX_EN   0x30
+#define PNP_IDX_IO0  0x60
+#define PNP_IDX_IO1  0x62
+#define PNP_IDX_IO2  0x64
+#define PNP_IDX_IO3  0x66
+#define PNP_IDX_IRQ0 0x70
+#define PNP_IDX_IRQ1 0x72
+#define PNP_IDX_DRQ0 0x74
+#define PNP_IDX_DRQ1 0x75
+#define PNP_IDX_MSC0 0xf0
+#define PNP_IDX_MSC1 0xf1
+
+/* Generic functions for pnp devices */
+
+/*
+ * pnp device is a 16-bit integer composed of its i/o port address at high byte
+ * and logic function number at low byte.
+ */
+#define PNP_DEV(PORT, FUNC) (((PORT) << 8) | (FUNC))
+
+static inline void pnp_write_config(uint16_t dev, uint8_t reg, uint8_t value)
+{
+	uint8_t port = dev >> 8;
+
+	outb(reg, port);
+	outb(value, port + 1);
+}
+
+static inline uint8_t pnp_read_config(uint16_t dev, uint8_t reg)
+{
+	uint8_t port = dev >> 8;
+
+	outb(reg, port);
+	return inb(port + 1);
+}
+
+static inline void pnp_set_logical_device(uint16_t dev)
+{
+	uint8_t device = dev & 0xff;
+
+	pnp_write_config(dev, 0x07, device);
+}
+
+static inline void pnp_set_enable(uint16_t dev, int enable)
+{
+	pnp_write_config(dev, PNP_IDX_EN, enable ? 1 : 0);
+}
+
+static inline int pnp_read_enable(uint16_t dev)
+{
+	return !!pnp_read_config(dev, PNP_IDX_EN);
+}
+
+static inline void pnp_set_iobase(uint16_t dev, uint8_t index, uint16_t iobase)
+{
+	pnp_write_config(dev, index + 0, (iobase >> 8) & 0xff);
+	pnp_write_config(dev, index + 1, iobase & 0xff);
+}
+
+static inline uint16_t pnp_read_iobase(uint16_t dev, uint8_t index)
+{
+	return ((uint16_t)(pnp_read_config(dev, index)) << 8) |
+		pnp_read_config(dev, index + 1);
+}
+
+static inline void pnp_set_irq(uint16_t dev, uint8_t index, unsigned irq)
+{
+	pnp_write_config(dev, index, irq);
+}
+
+static inline void pnp_set_drq(uint16_t dev, uint8_t index, unsigned drq)
+{
+	pnp_write_config(dev, index, drq & 0xff);
+}
+
+#endif /* _ASM_PNP_DEF_H_ */

drivers/misc/Makefile

@@ -24,6 +24,7 @@ obj-$(CONFIG_PDSP188x) += pdsp188x.o
 ifdef CONFIG_DM_I2C
 obj-$(CONFIG_SANDBOX) += i2c_eeprom_emul.o
 endif
+obj-$(CONFIG_SMSC_LPC47M) += smsc_lpc47m.o
 obj-$(CONFIG_STATUS_LED) += status_led.o
 obj-$(CONFIG_TWL4030_LED) += twl4030_led.o
 obj-$(CONFIG_FSL_IFC) += fsl_ifc.o

drivers/misc/smsc_lpc47m.c

+/*
+ * Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/pnp_def.h>
+
+static void pnp_enter_conf_state(u16 dev)
+{
+	u16 port = dev >> 8;
+
+	outb(0x55, port);
+}
+
+static void pnp_exit_conf_state(u16 dev)
+{
+	u16 port = dev >> 8;
+
+	outb(0xaa, port);
+}
+
+void lpc47m_enable_serial(u16 dev, u16 iobase)
+{
+	pnp_enter_conf_state(dev);
+	pnp_set_logical_device(dev);
+	pnp_set_enable(dev, 0);
+	pnp_set_iobase(dev, PNP_IDX_IO0, iobase);
+	pnp_set_enable(dev, 1);
+	pnp_exit_conf_state(dev);
+}

include/smsc_lpc47m.h

+/*
+ * Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _SMSC_LPC47M_H_
+#define _SMSC_LPC47M_H_
+
+/**
+ * Configure the base I/O port of the specified serial device and enable the
+ * serial device.
+ *
+ * @dev: High 8 bits = Super I/O port, low 8 bits = logical device number.
+ * @iobase: Processor I/O port address to assign to this serial device.
+ */
+void lpc47m_enable_serial(u16 dev, u16 iobase);
+
+#endif /* _SMSC_LPC47M_H_ */