ipmi: Create a platform device for a DMI-specified IPMI interface

Create a platform device for each IPMI device in the DMI table,
a separate kind of device for SSIF types and for KCS, BT, and
SMIC types.  This is so auto-loading IPMI devices will work
from just SMBIOS tables.

This also adds the ability to extract the slave address from
the SMBIOS tables, so that when the driver uses ACPI-specified
interfaces, it can still extract the slave address from SMBIOS.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: Andy Lutomirski <luto@kernel.org>

1 files changed, 273 insertions, 0 deletions

diff --git a/drivers/char/ipmi/ipmi_dmi.c b/drivers/char/ipmi/ipmi_dmi.c
new file mode 100644
index 000000000000..2a84401dea05
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_dmi.c
@@ -0,0 +1,273 @@
+/*
+ * A hack to create a platform device from a DMI entry.  This will
+ * allow autoloading of the IPMI drive based on SMBIOS entries.
+ */
+
+#include <linux/ipmi.h>
+#include <linux/init.h>
+#include <linux/dmi.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include "ipmi_dmi.h"
+
+struct ipmi_dmi_info {
+	int type;
+	u32 flags;
+	unsigned long addr;
+	u8 slave_addr;
+	struct ipmi_dmi_info *next;
+};
+
+static struct ipmi_dmi_info *ipmi_dmi_infos;
+
+static int ipmi_dmi_nr __initdata;
+
+static void __init dmi_add_platform_ipmi(unsigned long base_addr,
+					 u32 flags,
+					 u8 slave_addr,
+					 int irq,
+					 int offset,
+					 int type)
+{
+	struct platform_device *pdev;
+	struct resource r[4];
+	unsigned int num_r = 1, size;
+	struct property_entry p[4] = {
+		PROPERTY_ENTRY_U8("slave-addr", slave_addr),
+		PROPERTY_ENTRY_U8("ipmi-type", type),
+		PROPERTY_ENTRY_U16("i2c-addr", base_addr),
+		{ }
+	};
+	char *name, *override;
+	int rv;
+	struct ipmi_dmi_info *info;
+
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		pr_warn("ipmi:dmi: Could not allocate dmi info\n");
+	} else {
+		info->type = type;
+		info->flags = flags;
+		info->addr = base_addr;
+		info->slave_addr = slave_addr;
+		info->next = ipmi_dmi_infos;
+		ipmi_dmi_infos = info;
+	}
+
+	name = "dmi-ipmi-si";
+	override = "ipmi_si";
+	switch (type) {
+	case IPMI_DMI_TYPE_SSIF:
+		name = "dmi-ipmi-ssif";
+		override = "ipmi_ssif";
+		offset = 1;
+		size = 1;
+		break;
+	case IPMI_DMI_TYPE_BT:
+		size = 3;
+		break;
+	case IPMI_DMI_TYPE_KCS:
+	case IPMI_DMI_TYPE_SMIC:
+		size = 2;
+		break;
+	default:
+		pr_err("ipmi:dmi: Invalid IPMI type: %d", type);
+		return;
+	}
+
+	pdev = platform_device_alloc(name, ipmi_dmi_nr);
+	if (!pdev) {
+		pr_err("ipmi:dmi: Error allocation IPMI platform device");
+		return;
+	}
+	pdev->driver_override = override;
+
+	if (type == IPMI_DMI_TYPE_SSIF)
+		goto add_properties;
+
+	memset(r, 0, sizeof(r));
+
+	r[0].start = base_addr;
+	r[0].end = r[0].start + offset - 1;
+	r[0].name = "IPMI Address 1";
+	r[0].flags = flags;
+
+	if (size > 1) {
+		r[1].start = r[0].start + offset;
+		r[1].end = r[1].start + offset - 1;
+		r[1].name = "IPMI Address 2";
+		r[1].flags = flags;
+		num_r++;
+	}
+
+	if (size > 2) {
+		r[2].start = r[1].start + offset;
+		r[2].end = r[2].start + offset - 1;
+		r[2].name = "IPMI Address 3";
+		r[2].flags = flags;
+		num_r++;
+	}
+
+	if (irq) {
+		r[num_r].start = irq;
+		r[num_r].end = irq;
+		r[num_r].name = "IPMI IRQ";
+		r[num_r].flags = IORESOURCE_IRQ;
+		num_r++;
+	}
+
+	rv = platform_device_add_resources(pdev, r, num_r);
+	if (rv) {
+		dev_err(&pdev->dev,
+			"ipmi:dmi: Unable to add resources: %d\n", rv);
+		goto err;
+	}
+
+add_properties:
+	rv = platform_device_add_properties(pdev, p);
+	if (rv) {
+		dev_err(&pdev->dev,
+			"ipmi:dmi: Unable to add properties: %d\n", rv);
+		goto err;
+	}
+
+	rv = platform_device_add(pdev);
+	if (rv) {
+		dev_err(&pdev->dev, "ipmi:dmi: Unable to add device: %d\n", rv);
+		goto err;
+	}
+
+	ipmi_dmi_nr++;
+	return;
+
+err:
+	platform_device_put(pdev);
+}
+
+/*
+ * Look up the slave address for a given interface.  This is here
+ * because ACPI doesn't have a slave address while SMBIOS does, but we
+ * prefer using ACPI so the ACPI code can use the IPMI namespace.
+ * This function allows an ACPI-specified IPMI device to look up the
+ * slave address from the DMI table.
+ */
+int ipmi_dmi_get_slave_addr(int type, u32 flags, unsigned long base_addr)
+{
+	struct ipmi_dmi_info *info = ipmi_dmi_infos;
+
+	while (info) {
+		if (info->type == type &&
+		    info->flags == flags &&
+		    info->addr == base_addr)
+			return info->slave_addr;
+		info = info->next;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(ipmi_dmi_get_slave_addr);
+
+#define DMI_IPMI_MIN_LENGTH	0x10
+#define DMI_IPMI_VER2_LENGTH	0x12
+#define DMI_IPMI_TYPE		4
+#define DMI_IPMI_SLAVEADDR	6
+#define DMI_IPMI_ADDR		8
+#define DMI_IPMI_ACCESS		0x10
+#define DMI_IPMI_IRQ		0x11
+#define DMI_IPMI_IO_MASK	0xfffe
+
+static void __init dmi_decode_ipmi(const struct dmi_header *dm)
+{
+	const u8	*data = (const u8 *) dm;
+	u32             flags = IORESOURCE_IO;
+	unsigned long	base_addr;
+	u8              len = dm->length;
+	u8              slave_addr;
+	int             irq = 0, offset;
+	int             type;
+
+	if (len < DMI_IPMI_MIN_LENGTH)
+		return;
+
+	type = data[DMI_IPMI_TYPE];
+	slave_addr = data[DMI_IPMI_SLAVEADDR];
+
+	memcpy(&base_addr, data + DMI_IPMI_ADDR, sizeof(unsigned long));
+	if (len >= DMI_IPMI_VER2_LENGTH) {
+		if (type == IPMI_DMI_TYPE_SSIF) {
+			offset = 0;
+			flags = 0;
+			base_addr = data[DMI_IPMI_ADDR] >> 1;
+			if (base_addr == 0) {
+				/*
+				 * Some broken systems put the I2C address in
+				 * the slave address field.  We try to
+				 * accommodate them here.
+				 */
+				base_addr = data[DMI_IPMI_SLAVEADDR] >> 1;
+				slave_addr = 0;
+			}
+		} else {
+			if (base_addr & 1) {
+				/* I/O */
+				base_addr &= DMI_IPMI_IO_MASK;
+			} else {
+				/* Memory */
+				flags = IORESOURCE_MEM;
+			}
+
+			/*
+			 * If bit 4 of byte 0x10 is set, then the lsb
+			 * for the address is odd.
+			 */
+			base_addr |= (data[DMI_IPMI_ACCESS] >> 4) & 1;
+
+			irq = data[DMI_IPMI_IRQ];
+
+			/*
+			 * The top two bits of byte 0x10 hold the
+			 * register spacing.
+			 */
+			switch ((data[DMI_IPMI_ACCESS] >> 6) & 3) {
+			case 0: /* Byte boundaries */
+				offset = 1;
+				break;
+			case 1: /* 32-bit boundaries */
+				offset = 4;
+				break;
+			case 2: /* 16-byte boundaries */
+				offset = 16;
+				break;
+			default:
+				pr_err("ipmi:dmi: Invalid offset: 0");
+				return;
+			}
+		}
+	} else {
+		/* Old DMI spec. */
+		/*
+		 * Note that technically, the lower bit of the base
+		 * address should be 1 if the address is I/O and 0 if
+		 * the address is in memory.  So many systems get that
+		 * wrong (and all that I have seen are I/O) so we just
+		 * ignore that bit and assume I/O.  Systems that use
+		 * memory should use the newer spec, anyway.
+		 */
+		base_addr = base_addr & DMI_IPMI_IO_MASK;
+		offset = 1;
+	}
+
+	dmi_add_platform_ipmi(base_addr, flags, slave_addr, irq,
+			      offset, type);
+}
+
+static int __init scan_for_dmi_ipmi(void)
+{
+	const struct dmi_device *dev = NULL;
+
+	while ((dev = dmi_find_device(DMI_DEV_TYPE_IPMI, NULL, dev)))
+		dmi_decode_ipmi((const struct dmi_header *) dev->device_data);
+
+	return 0;
+}
+subsys_initcall(scan_for_dmi_ipmi);