FMC: add a software carrier driver

This fake carrier is designed to help FMC users understand how a
carrier driver works, and to experiment the behaviour with EEPROM
reprogramming (with a mezzanine driver commited later). This carrier
can register up to 4 (fake) mezzanines.

We have real carriers (both on PCI-E and VME), but they are bigger
things and are not part of this submission.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Juan David Gonzalez Cobas <dcobas@cern.ch>
Acked-by: Emilio G. Cota <cota@braap.org>
Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 368 insertions, 0 deletions

diff --git a/drivers/fmc/Kconfig b/drivers/fmc/Kconfig
index e28790267c69..505e96b02a93 100644
--- a/drivers/fmc/Kconfig
+++ b/drivers/fmc/Kconfig
@@ -15,3 +15,14 @@ menuconfig FMC
           The framework was born outside of the kernel and at this time
           the off-tree code base is more complete.  Code and documentation
           is at git://ohwr.org/fmc-projects/fmc-bus.git .
+
+if FMC
+
+config FMC_FAKEDEV
+        tristate "FMC fake device (software testing)"
+        help
+          This is a fake carrier, bringing a default EEPROM content
+          that can be rewritten at run time and usef for matching
+          mezzanines.
+
+endif # FMC
diff --git a/drivers/fmc/Makefile b/drivers/fmc/Makefile
index df9893972a62..9832b79976b1 100644
--- a/drivers/fmc/Makefile
+++ b/drivers/fmc/Makefile
@@ -6,3 +6,5 @@ fmc-y += fmc-match.o
 fmc-y += fmc-sdb.o
 fmc-y += fru-parse.o
 fmc-y += fmc-dump.o
+
+obj-$(CONFIG_FMC_FAKEDEV) += fmc-fakedev.o
diff --git a/drivers/fmc/fmc-fakedev.c b/drivers/fmc/fmc-fakedev.c
new file mode 100644
index 000000000000..bec94ac0764c
--- /dev/null
+++ b/drivers/fmc/fmc-fakedev.c
@@ -0,0 +1,355 @@
+/*
+ * Copyright (C) 2012 CERN (www.cern.ch)
+ * Author: Alessandro Rubini <rubini@gnudd.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * The software is provided "as is"; the copyright holders disclaim
+ * all warranties and liabilities, to the extent permitted by
+ * applicable law.
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/firmware.h>
+#include <linux/workqueue.h>
+#include <linux/err.h>
+#include <linux/fmc.h>
+
+#define FF_EEPROM_SIZE          8192    /* The standard eeprom size */
+#define FF_MAX_MEZZANINES       4       /* Fakes a multi-mezzanine carrier */
+
+/* The user can pass up to 4 names of eeprom images to load */
+static char *ff_eeprom[FF_MAX_MEZZANINES];
+static int ff_nr_eeprom;
+module_param_array_named(eeprom, ff_eeprom, charp, &ff_nr_eeprom, 0444);
+
+/* The user can ask for a multi-mezzanine carrier, with the default eeprom */
+static int ff_nr_dev = 1;
+module_param_named(ndev, ff_nr_dev, int, 0444);
+
+
+/* Lazily, don't support the "standard" module parameters */
+
+/*
+ * Eeprom built from these commands:
+
+        ../fru-generator -v fake-vendor -n fake-design-for-testing \
+                -s 01234 -p none > IPMI-FRU
+
+        gensdbfs . ../fake-eeprom.bin
+*/
+static char ff_eeimg[FF_MAX_MEZZANINES][FF_EEPROM_SIZE] = {
+        {
+        0x01, 0x00, 0x00, 0x01, 0x00, 0x0c, 0x00, 0xf2, 0x01, 0x0b, 0x00, 0xb2,
+        0x86, 0x87, 0xcb, 0x66, 0x61, 0x6b, 0x65, 0x2d, 0x76, 0x65, 0x6e, 0x64,
+        0x6f, 0x72, 0xd7, 0x66, 0x61, 0x6b, 0x65, 0x2d, 0x64, 0x65, 0x73, 0x69,
+        0x67, 0x6e, 0x2d, 0x66, 0x6f, 0x72, 0x2d, 0x74, 0x65, 0x73, 0x74, 0x69,
+        0x6e, 0x67, 0xc5, 0x30, 0x31, 0x32, 0x33, 0x34, 0xc4, 0x6e, 0x6f, 0x6e,
+        0x65, 0xda, 0x32, 0x30, 0x31, 0x32, 0x2d, 0x31, 0x31, 0x2d, 0x31, 0x39,
+        0x20, 0x32, 0x32, 0x3a, 0x34, 0x32, 0x3a, 0x33, 0x30, 0x2e, 0x30, 0x37,
+        0x34, 0x30, 0x35, 0x35, 0xc1, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x87,
+        0x02, 0x02, 0x0d, 0xf7, 0xf8, 0x02, 0xb0, 0x04, 0x74, 0x04, 0xec, 0x04,
+        0x00, 0x00, 0x00, 0x00, 0xe8, 0x03, 0x02, 0x02, 0x0d, 0x5c, 0x93, 0x01,
+        0x4a, 0x01, 0x39, 0x01, 0x5a, 0x01, 0x00, 0x00, 0x00, 0x00, 0xb8, 0x0b,
+        0x02, 0x02, 0x0d, 0x63, 0x8c, 0x00, 0xfa, 0x00, 0xed, 0x00, 0x06, 0x01,
+        0x00, 0x00, 0x00, 0x00, 0xa0, 0x0f, 0x01, 0x02, 0x0d, 0xfb, 0xf5, 0x05,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x01, 0x02, 0x0d, 0xfc, 0xf4, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x0d, 0xfd, 0xf3, 0x03,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0xfa, 0x82, 0x0b, 0xea, 0x8f, 0xa2, 0x12, 0x00, 0x00, 0x1e, 0x44, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x53, 0x44, 0x42, 0x2d, 0x00, 0x03, 0x01, 0x01,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x01, 0xc4, 0x46, 0x69, 0x6c, 0x65, 0x44, 0x61, 0x74, 0x61,
+        0x2e, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
+        0x2e, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+        0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xc0,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xc4, 0x46, 0x69, 0x6c, 0x65,
+        0x44, 0x61, 0x74, 0x61, 0x6e, 0x61, 0x6d, 0x65, 0x00, 0x00, 0x00, 0x01,
+        0x00, 0x00, 0x00, 0x00, 0x6e, 0x61, 0x6d, 0x65, 0x20, 0x20, 0x20, 0x20,
+        0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x01,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xdf,
+        0x46, 0x69, 0x6c, 0x65, 0x44, 0x61, 0x74, 0x61, 0x49, 0x50, 0x4d, 0x49,
+        0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x49, 0x50, 0x4d, 0x49,
+        0x2d, 0x46, 0x52, 0x55, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+        0x20, 0x20, 0x20, 0x01, 0x66, 0x61, 0x6b, 0x65, 0x0a,
+        },
+};
+
+struct ff_dev {
+        struct fmc_device *fmc[FF_MAX_MEZZANINES];
+        struct device dev;
+};
+
+static struct ff_dev *ff_current_dev; /* We have 1 carrier, 1 slot */
+
+static int ff_reprogram(struct fmc_device *fmc, struct fmc_driver *drv,
+                          char *gw)
+{
+        const struct firmware *fw;
+        int ret;
+
+        if (!gw) {
+                /* program golden: success */
+                fmc->flags &= ~FMC_DEVICE_HAS_CUSTOM;
+                fmc->flags |= FMC_DEVICE_HAS_GOLDEN;
+                return 0;
+        }
+
+        dev_info(&fmc->dev, "reprogramming with %s\n", gw);
+        ret = request_firmware(&fw, gw, &fmc->dev);
+        if (ret < 0) {
+                dev_warn(&fmc->dev, "request firmware \"%s\": error %i\n",
+                         gw, ret);
+                goto out;
+        }
+        fmc->flags &= ~FMC_DEVICE_HAS_GOLDEN;
+        fmc->flags |= FMC_DEVICE_HAS_CUSTOM;
+
+out:
+        release_firmware(fw);
+        return ret;
+}
+
+static int ff_irq_request(struct fmc_device *fmc, irq_handler_t handler,
+                            char *name, int flags)
+{
+        return -EOPNOTSUPP;
+}
+
+/* FIXME: should also have some fake FMC GPIO mapping */
+
+
+/*
+ * This work function is called when we changed the eeprom. It removes the
+ * current fmc device and registers a new one, with different identifiers.
+ */
+static struct ff_dev *ff_dev_create(void); /* defined later */
+
+static void ff_work_fn(struct work_struct *work)
+{
+        struct ff_dev *ff = ff_current_dev;
+        int ret;
+
+        fmc_device_unregister_n(ff->fmc, ff_nr_dev);
+        device_unregister(&ff->dev);
+        ff_current_dev = NULL;
+
+        ff = ff_dev_create();
+        if (IS_ERR(ff)) {
+                pr_warning("%s: can't re-create FMC devices\n", __func__);
+                return;
+        }
+        ret = fmc_device_register_n(ff->fmc, ff_nr_dev);
+        if (ret < 0) {
+                dev_warn(&ff->dev, "can't re-register FMC devices\n");
+                device_unregister(&ff->dev);
+                return;
+        }
+
+        ff_current_dev = ff;
+}
+
+static DECLARE_DELAYED_WORK(ff_work, ff_work_fn);
+
+
+/* low-level i2c */
+static int ff_eeprom_read(struct fmc_device *fmc, uint32_t offset,
+                void *buf, size_t size)
+{
+        if (offset > FF_EEPROM_SIZE)
+                return -EINVAL;
+        if (offset + size > FF_EEPROM_SIZE)
+                size = FF_EEPROM_SIZE - offset;
+        memcpy(buf, fmc->eeprom + offset, size);
+        return size;
+}
+
+static int ff_eeprom_write(struct fmc_device *fmc, uint32_t offset,
+                    const void *buf, size_t size)
+{
+        if (offset > FF_EEPROM_SIZE)
+                return -EINVAL;
+        if (offset + size > FF_EEPROM_SIZE)
+                size = FF_EEPROM_SIZE - offset;
+        dev_info(&fmc->dev, "write_eeprom: offset %i, size %zi\n",
+                 (int)offset, size);
+        memcpy(fmc->eeprom + offset, buf, size);
+        schedule_delayed_work(&ff_work, HZ * 2); /* remove, replug, in 2s */
+        return size;
+}
+
+/* i2c operations for fmc */
+static int ff_read_ee(struct fmc_device *fmc, int pos, void *data, int len)
+{
+        if (!(fmc->flags & FMC_DEVICE_HAS_GOLDEN))
+                return -EOPNOTSUPP;
+        return ff_eeprom_read(fmc, pos, data, len);
+}
+
+static int ff_write_ee(struct fmc_device *fmc, int pos,
+                         const void *data, int len)
+{
+        if (!(fmc->flags & FMC_DEVICE_HAS_GOLDEN))
+                return -EOPNOTSUPP;
+        return ff_eeprom_write(fmc, pos, data, len);
+}
+
+/* readl and writel do not do anything. Don't waste RAM with "base" */
+static uint32_t ff_readl(struct fmc_device *fmc, int offset)
+{
+        return 0;
+}
+
+static void ff_writel(struct fmc_device *fmc, uint32_t value, int offset)
+{
+        return;
+}
+
+/* validate is useful so fmc-write-eeprom will not reprogram every 2 seconds */
+static int ff_validate(struct fmc_device *fmc, struct fmc_driver *drv)
+{
+        int i;
+
+        if (!drv->busid_n)
+                return 0; /* everyhing is valid */
+        for (i = 0; i < drv->busid_n; i++)
+                if (drv->busid_val[i] == fmc->device_id)
+                        return i;
+        return -ENOENT;
+}
+
+
+
+static struct fmc_operations ff_fmc_operations = {
+        .readl =                ff_readl,
+        .writel =               ff_writel,
+        .reprogram =            ff_reprogram,
+        .irq_request =          ff_irq_request,
+        .read_ee =              ff_read_ee,
+        .write_ee =             ff_write_ee,
+        .validate =             ff_validate,
+};
+
+/* This device is kmalloced: release it */
+static void ff_dev_release(struct device *dev)
+{
+        struct ff_dev *ff = container_of(dev, struct ff_dev, dev);
+        kfree(ff);
+}
+
+static struct fmc_device ff_template_fmc = {
+        .version = FMC_VERSION,
+        .owner = THIS_MODULE,
+        .carrier_name = "fake-fmc-carrier",
+        .device_id = 0xf001, /* fool */
+        .eeprom_len = sizeof(ff_eeimg[0]),
+        .memlen = 0x1000, /* 4k, to show something */
+        .op = &ff_fmc_operations,
+        .hwdev = NULL, /* filled at creation time */
+        .flags = FMC_DEVICE_HAS_GOLDEN,
+};
+
+static struct ff_dev *ff_dev_create(void)
+{
+        struct ff_dev *ff;
+        struct fmc_device *fmc;
+        int i, ret;
+
+        ff = kzalloc(sizeof(*ff), GFP_KERNEL);
+        if (!ff)
+                return ERR_PTR(-ENOMEM);
+        dev_set_name(&ff->dev, "fake-fmc-carrier");
+        ff->dev.release = ff_dev_release;
+
+        ret = device_register(&ff->dev);
+        if (ret < 0) {
+                put_device(&ff->dev);
+                return ERR_PTR(ret);
+        }
+
+        /* Create fmc structures that refer to this new "hw" device */
+        for (i = 0; i < ff_nr_dev; i++) {
+                fmc = kmemdup(&ff_template_fmc, sizeof(ff_template_fmc),
+                              GFP_KERNEL);
+                fmc->hwdev = &ff->dev;
+                fmc->carrier_data = ff;
+                fmc->nr_slots = ff_nr_dev;
+                /* the following fields are different for each slot */
+                fmc->eeprom = ff_eeimg[i];
+                fmc->eeprom_addr = 0x50 + 2 * i;
+                fmc->slot_id = i;
+                ff->fmc[i] = fmc;
+                /* increment the identifier, each must be different */
+                ff_template_fmc.device_id++;
+        }
+        return ff;
+}
+
+/* init and exit */
+static int ff_init(void)
+{
+        struct ff_dev *ff;
+        const struct firmware *fw;
+        int i, len, ret = 0;
+
+        /* Replicate the default eeprom for the max number of mezzanines */
+        for (i = 1; i < FF_MAX_MEZZANINES; i++)
+                memcpy(ff_eeimg[i], ff_eeimg[0], sizeof(ff_eeimg[0]));
+
+        if (ff_nr_eeprom > ff_nr_dev)
+                ff_nr_dev = ff_nr_eeprom;
+
+        ff = ff_dev_create();
+        if (IS_ERR(ff))
+                return PTR_ERR(ff);
+
+        /* If the user passed "eeprom=" as a parameter, fetch them */
+        for (i = 0; i < ff_nr_eeprom; i++) {
+                if (!strlen(ff_eeprom[i]))
+                        continue;
+                ret = request_firmware(&fw, ff_eeprom[i], &ff->dev);
+                if (ret < 0) {
+                        dev_err(&ff->dev, "Mezzanine %i: can't load \"%s\" "
+                                "(error %i)\n", i, ff_eeprom[i], -ret);
+                } else {
+                        len = min_t(size_t, fw->size, (size_t)FF_EEPROM_SIZE);
+                        memcpy(ff_eeimg[i], fw->data, len);
+                        release_firmware(fw);
+                        dev_info(&ff->dev, "Mezzanine %i: eeprom \"%s\"\n", i,
+                                ff_eeprom[i]);
+                }
+        }
+
+        ret = fmc_device_register_n(ff->fmc, ff_nr_dev);
+        if (ret) {
+                device_unregister(&ff->dev);
+                return ret;
+        }
+        ff_current_dev = ff;
+        return ret;
+}
+
+static void ff_exit(void)
+{
+        if (ff_current_dev) {
+                fmc_device_unregister_n(ff_current_dev->fmc, ff_nr_dev);
+                device_unregister(&ff_current_dev->dev);
+        }
+        cancel_delayed_work_sync(&ff_work);
+}
+
+module_init(ff_init);
+module_exit(ff_exit);
+
+MODULE_LICENSE("Dual BSD/GPL");