FMC: add core bus driver

This module offers registration services for both carriers
(i.e. devices) and mezzanines (i.e. drivers). The matching for devices
and drivers is performed according to the IPMI standard for FRU
devices (Field Replaceable Units).

The code includes support for parsing an SDB tree if present in the FPGA,
and dumping it for diagnostics. SDB is not mandatory.

Files in this commit correspond to commit ab23167f in the master branch
of the project hosted on ohwr.org.

Signed-off-by: Alessandro Rubini <[email protected]>
Acked-by: Juan David Gonzalez Cobas <[email protected]>
Acked-by: Emilio G. Cota <[email protected]>
Acked-by: Samuel Iglesias Gonsalvez <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/fmc/Makefile

@@ -2,3 +2,7 @@
 obj-$(CONFIG_FMC) += fmc.o
 
 fmc-y = fmc-core.o
+fmc-y += fmc-match.o
+fmc-y += fmc-sdb.o
+fmc-y += fru-parse.o
+fmc-y += fmc-dump.o

drivers/fmc/fmc-core.c

@@ -1,13 +1,285 @@
-/* Temporary placeholder so the empty code can build */
+/*
+ * Copyright (C) 2012 CERN (www.cern.ch)
+ * Author: Alessandro Rubini <[email protected]>
+ *
+ * Released according to the GNU GPL, version 2 or any later version.
+ *
+ * This work is part of the White Rabbit project, a research effort led
+ * by CERN, the European Institute for Nuclear Research.
+ */
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/device.h>
+#include <linux/fmc.h>
+
+static int fmc_check_version(unsigned long version, const char *name)
+{
+	if (__FMC_MAJOR(version) != FMC_MAJOR) {
+		pr_err("%s: \"%s\" has wrong major (has %li, expected %i)\n",
+		       __func__, name, __FMC_MAJOR(version), FMC_MAJOR);
+		return -EINVAL;
+	}
+
+	if (__FMC_MINOR(version) != FMC_MINOR)
+		pr_info("%s: \"%s\" has wrong minor (has %li, expected %i)\n",
+		       __func__, name, __FMC_MINOR(version), FMC_MINOR);
+	return 0;
+}
+
+static int fmc_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	/* struct fmc_device *fdev = to_fmc_device(dev); */
+
+	/* FIXME: The MODALIAS */
+	add_uevent_var(env, "MODALIAS=%s", "fmc");
+	return 0;
+}
+
+static int fmc_probe(struct device *dev)
+{
+	struct fmc_driver *fdrv = to_fmc_driver(dev->driver);
+	struct fmc_device *fdev = to_fmc_device(dev);
+
+	return fdrv->probe(fdev);
+}
+
+static int fmc_remove(struct device *dev)
+{
+	struct fmc_driver *fdrv = to_fmc_driver(dev->driver);
+	struct fmc_device *fdev = to_fmc_device(dev);
+
+	return fdrv->remove(fdev);
+}
+
+static void fmc_shutdown(struct device *dev)
+{
+	/* not implemented but mandatory */
+}
 
 static struct bus_type fmc_bus_type = {
 	.name = "fmc",
+	.match = fmc_match,
+	.uevent = fmc_uevent,
+	.probe = fmc_probe,
+	.remove = fmc_remove,
+	.shutdown = fmc_shutdown,
 };
 
+static void fmc_release(struct device *dev)
+{
+	struct fmc_device *fmc = container_of(dev, struct fmc_device, dev);
+
+	kfree(fmc);
+}
+
+/*
+ * The eeprom is exported in sysfs, through a binary attribute
+ */
+
+static ssize_t fmc_read_eeprom(struct file *file, struct kobject *kobj,
+			   struct bin_attribute *bin_attr,
+			   char *buf, loff_t off, size_t count)
+{
+	struct device *dev;
+	struct fmc_device *fmc;
+	int eelen;
+
+	dev = container_of(kobj, struct device, kobj);
+	fmc = container_of(dev, struct fmc_device, dev);
+	eelen = fmc->eeprom_len;
+	if (off > eelen)
+		return -ESPIPE;
+	if (off == eelen)
+		return 0; /* EOF */
+	if (off + count > eelen)
+		count = eelen - off;
+	memcpy(buf, fmc->eeprom + off, count);
+	return count;
+}
+
+static struct bin_attribute fmc_eeprom_attr = {
+	.attr = { .name = "eeprom", .mode = S_IRUGO, },
+	.size = 8192, /* more or less standard */
+	.read = fmc_read_eeprom,
+};
+
+/*
+ * Functions for client modules follow
+ */
+
+int fmc_driver_register(struct fmc_driver *drv)
+{
+	if (fmc_check_version(drv->version, drv->driver.name))
+		return -EINVAL;
+	drv->driver.bus = &fmc_bus_type;
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL(fmc_driver_register);
+
+void fmc_driver_unregister(struct fmc_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL(fmc_driver_unregister);
+
+/*
+ * When a device set is registered, all eeproms must be read
+ * and all FRUs must be parsed
+ */
+int fmc_device_register_n(struct fmc_device **devs, int n)
+{
+	struct fmc_device *fmc, **devarray;
+	uint32_t device_id;
+	int i, ret = 0;
+
+	if (n < 1)
+		return 0;
+
+	/* Check the version of the first data structure (function prints) */
+	if (fmc_check_version(devs[0]->version, devs[0]->carrier_name))
+		return -EINVAL;
+
+	devarray = kmemdup(devs, n * sizeof(*devs), GFP_KERNEL);
+	if (!devarray)
+		return -ENOMEM;
+
+	/* Make all other checks before continuing, for all devices */
+	for (i = 0; i < n; i++) {
+		fmc = devarray[i];
+		if (!fmc->hwdev) {
+			pr_err("%s: device nr. %i has no hwdev pointer\n",
+			       __func__, i);
+			ret = -EINVAL;
+			break;
+		}
+		if (fmc->flags == FMC_DEVICE_NO_MEZZANINE) {
+			dev_info(fmc->hwdev, "absent mezzanine in slot %d\n",
+				 fmc->slot_id);
+			continue;
+		}
+		if (!fmc->eeprom) {
+			dev_err(fmc->hwdev, "no eeprom provided for slot %i\n",
+				fmc->slot_id);
+			ret = -EINVAL;
+		}
+		if (!fmc->eeprom_addr) {
+			dev_err(fmc->hwdev, "no eeprom_addr for slot %i\n",
+				fmc->slot_id);
+			ret = -EINVAL;
+		}
+		if (!fmc->carrier_name || !fmc->carrier_data ||
+		    !fmc->device_id) {
+			dev_err(fmc->hwdev,
+				"deivce nr %i: carrier name, "
+				"data or dev_id not set\n", i);
+			ret = -EINVAL;
+		}
+		if (ret)
+			break;
+
+	}
+	if (ret) {
+		kfree(devarray);
+		return ret;
+	}
+
+	/* Validation is ok. Now init and register the devices */
+	for (i = 0; i < n; i++) {
+		fmc = devarray[i];
+
+		if (fmc->flags == FMC_DEVICE_NO_MEZZANINE)
+			continue; /* dev_info already done above */
+
+		fmc->nr_slots = n; /* each slot must know how many are there */
+		fmc->devarray = devarray;
+
+		device_initialize(&fmc->dev);
+		fmc->dev.release = fmc_release;
+		fmc->dev.parent = fmc->hwdev;
+
+		/* Fill the identification stuff (may fail) */
+		fmc_fill_id_info(fmc);
+
+		fmc->dev.bus = &fmc_bus_type;
+
+		/* Name from mezzanine info or carrier info. Or 0,1,2.. */
+		device_id = fmc->device_id;
+		if (!fmc->mezzanine_name)
+			dev_set_name(&fmc->dev, "fmc-%04x", device_id);
+		else
+			dev_set_name(&fmc->dev, "%s-%04x", fmc->mezzanine_name,
+				     device_id);
+		ret = device_add(&fmc->dev);
+		if (ret < 0) {
+			dev_err(fmc->hwdev, "Slot %i: Failed in registering "
+				"\"%s\"\n", fmc->slot_id, fmc->dev.kobj.name);
+			goto out;
+		}
+		ret = sysfs_create_bin_file(&fmc->dev.kobj, &fmc_eeprom_attr);
+		if (ret < 0) {
+			dev_err(&fmc->dev, "Failed in registering eeprom\n");
+			goto out1;
+		}
+		/* This device went well, give information to the user */
+		fmc_dump_eeprom(fmc);
+		fmc_dump_sdb(fmc);
+	}
+	return 0;
+
+out1:
+	device_del(&fmc->dev);
+out:
+	fmc_free_id_info(fmc);
+	put_device(&fmc->dev);
+
+	kfree(devarray);
+	for (i--; i >= 0; i--) {
+		sysfs_remove_bin_file(&devs[i]->dev.kobj, &fmc_eeprom_attr);
+		device_del(&devs[i]->dev);
+		fmc_free_id_info(devs[i]);
+		put_device(&devs[i]->dev);
+	}
+	return ret;
+
+}
+EXPORT_SYMBOL(fmc_device_register_n);
+
+int fmc_device_register(struct fmc_device *fmc)
+{
+	return fmc_device_register_n(&fmc, 1);
+}
+EXPORT_SYMBOL(fmc_device_register);
+
+void fmc_device_unregister_n(struct fmc_device **devs, int n)
+{
+	int i;
+
+	if (n < 1)
+		return;
+
+	/* Free devarray first, not used by the later loop */
+	kfree(devs[0]->devarray);
+
+	for (i = 0; i < n; i++) {
+		if (devs[i]->flags == FMC_DEVICE_NO_MEZZANINE)
+			continue;
+		sysfs_remove_bin_file(&devs[i]->dev.kobj, &fmc_eeprom_attr);
+		device_del(&devs[i]->dev);
+		fmc_free_id_info(devs[i]);
+		put_device(&devs[i]->dev);
+	}
+}
+EXPORT_SYMBOL(fmc_device_unregister_n);
+
+void fmc_device_unregister(struct fmc_device *fmc)
+{
+	fmc_device_unregister_n(&fmc, 1);
+}
+EXPORT_SYMBOL(fmc_device_unregister);
+
+/* Init and exit are trivial */
 static int fmc_init(void)
 {
 	return bus_register(&fmc_bus_type);

drivers/fmc/fmc-dump.c

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2013 CERN (www.cern.ch)
+ * Author: Alessandro Rubini <[email protected]>
+ *
+ * Released according to the GNU GPL, version 2 or any later version.
+ *
+ * This work is part of the White Rabbit project, a research effort led
+ * by CERN, the European Institute for Nuclear Research.
+ */
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/fmc.h>
+#include <linux/fmc-sdb.h>
+
+static int fmc_must_dump_eeprom;
+module_param_named(dump_eeprom, fmc_must_dump_eeprom, int, 0644);
+static int fmc_must_dump_sdb;
+module_param_named(dump_sdb, fmc_must_dump_sdb, int, 0644);
+
+#define LINELEN 16
+
+/* Dumping 8k takes oh so much: avoid duplicate lines */
+static const uint8_t *dump_line(int addr, const uint8_t *line,
+				const uint8_t *prev)
+{
+	int i;
+
+	if (!prev || memcmp(line, prev, LINELEN)) {
+		pr_info("%04x: ", addr);
+		for (i = 0; i < LINELEN; ) {
+			printk(KERN_CONT "%02x", line[i]);
+			i++;
+			printk(i & 3 ? " " : i & (LINELEN - 1) ? "  " : "\n");
+		}
+		return line;
+	}
+	/* repeated line */
+	if (line == prev + LINELEN)
+		pr_info("[...]\n");
+	return prev;
+}
+
+void fmc_dump_eeprom(const struct fmc_device *fmc)
+{
+	const uint8_t *line, *prev;
+	int i;
+
+	if (!fmc_must_dump_eeprom)
+		return;
+
+	pr_info("FMC: %s (%s), slot %i, device %s\n", dev_name(fmc->hwdev),
+		fmc->carrier_name, fmc->slot_id, dev_name(&fmc->dev));
+	pr_info("FMC: dumping eeprom 0x%x (%i) bytes\n", fmc->eeprom_len,
+	       fmc->eeprom_len);
+
+	line = fmc->eeprom;
+	prev = NULL;
+	for (i = 0; i < fmc->eeprom_len; i += LINELEN, line += LINELEN)
+		prev = dump_line(i, line, prev);
+}
+
+void fmc_dump_sdb(const struct fmc_device *fmc)
+{
+	const uint8_t *line, *prev;
+	int i, len;
+
+	if (!fmc->sdb)
+		return;
+	if (!fmc_must_dump_sdb)
+		return;
+
+	/* If the argument is not-zero, do simple dump (== show) */
+	if (fmc_must_dump_sdb > 0)
+		fmc_show_sdb_tree(fmc);
+
+	if (fmc_must_dump_sdb == 1)
+		return;
+
+	/* If bigger than 1, dump it seriously, to help debugging */
+
+	/*
+	 * Here we should really use libsdbfs (which is designed to
+	 * work in kernel space as well) , but it doesn't support
+	 * directories yet, and it requires better intergration (it
+	 * should be used instead of fmc-specific code).
+	 *
+	 * So, lazily, just dump the top-level array
+	 */
+	pr_info("FMC: %s (%s), slot %i, device %s\n", dev_name(fmc->hwdev),
+		fmc->carrier_name, fmc->slot_id, dev_name(&fmc->dev));
+	pr_info("FMC: poor dump of sdb first level:\n");
+
+	len = fmc->sdb->len * sizeof(union sdb_record);
+	line = (void *)fmc->sdb->record;
+	prev = NULL;
+	for (i = 0; i < len; i += LINELEN, line += LINELEN)
+		prev = dump_line(i, line, prev);
+	return;
+}