--- /dev/null
+/*
+ * Copyright (C) 2005, 2006 IBM Corporation
+ *
+ * Authors:
+ * Leendert van Doorn <leendert@watson.ibm.com>
+ * Kylene Hall <kjhall@us.ibm.com>
+ *
+ * Device driver for TCG/TCPA TPM (trusted platform module).
+ * Specifications at www.trustedcomputinggroup.org
+ *
+ * This device driver implements the TPM interface as defined in
+ * the TCG TPM Interface Spec version 1.2, revision 1.0.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ */
+#include <linux/pnp.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include "tpm.h"
+
+#define TPM_HEADER_SIZE 10
+
+enum tis_access {
+ TPM_ACCESS_VALID = 0x80,
+ TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
+ TPM_ACCESS_REQUEST_PENDING = 0x04,
+ TPM_ACCESS_REQUEST_USE = 0x02,
+};
+
+enum tis_status {
+ TPM_STS_VALID = 0x80,
+ TPM_STS_COMMAND_READY = 0x40,
+ TPM_STS_GO = 0x20,
+ TPM_STS_DATA_AVAIL = 0x10,
+ TPM_STS_DATA_EXPECT = 0x08,
+};
+
+enum tis_int_flags {
+ TPM_GLOBAL_INT_ENABLE = 0x80000000,
+ TPM_INTF_BURST_COUNT_STATIC = 0x100,
+ TPM_INTF_CMD_READY_INT = 0x080,
+ TPM_INTF_INT_EDGE_FALLING = 0x040,
+ TPM_INTF_INT_EDGE_RISING = 0x020,
+ TPM_INTF_INT_LEVEL_LOW = 0x010,
+ TPM_INTF_INT_LEVEL_HIGH = 0x008,
+ TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
+ TPM_INTF_STS_VALID_INT = 0x002,
+ TPM_INTF_DATA_AVAIL_INT = 0x001,
+};
+
+#define TPM_ACCESS(l) (0x0000 | ((l) << 12))
+#define TPM_INT_ENABLE(l) (0x0008 | ((l) << 12))
+#define TPM_INT_VECTOR(l) (0x000C | ((l) << 12))
+#define TPM_INT_STATUS(l) (0x0010 | ((l) << 12))
+#define TPM_INTF_CAPS(l) (0x0014 | ((l) << 12))
+#define TPM_STS(l) (0x0018 | ((l) << 12))
+#define TPM_DATA_FIFO(l) (0x0024 | ((l) << 12))
+
+#define TPM_DID_VID(l) (0x0F00 | ((l) << 12))
+#define TPM_RID(l) (0x0F04 | ((l) << 12))
+
+static LIST_HEAD(tis_chips);
+static DEFINE_SPINLOCK(tis_lock);
+
+static int check_locality(struct tpm_chip *chip, int l)
+{
+ if ((ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
+ (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
+ (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
+ return chip->vendor.locality = l;
+
+ return -1;
+}
+
+static void release_locality(struct tpm_chip *chip, int l, int force)
+{
+ if (force || (ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
+ (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
+ (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID))
+ iowrite8(TPM_ACCESS_ACTIVE_LOCALITY,
+ chip->vendor.iobase + TPM_ACCESS(l));
+}
+
+static int request_locality(struct tpm_chip *chip, int l)
+{
+ unsigned long stop;
+ long rc;
+
+ if (check_locality(chip, l) >= 0)
+ return l;
+
+ iowrite8(TPM_ACCESS_REQUEST_USE,
+ chip->vendor.iobase + TPM_ACCESS(l));
+
+ if (chip->vendor.irq) {
+ rc = wait_event_interruptible_timeout(chip->vendor.
+ int_queue,
+ (check_locality
+ (chip, l) >= 0),
+ msecs_to_jiffies
+ (chip->vendor.
+ timeout_a));
+ if (rc > 0)
+ return l;
+
+ } else {
+ /* wait for burstcount */
+ stop = jiffies + (HZ * chip->vendor.timeout_a / 1000);
+ do {
+ if (check_locality(chip, l) >= 0)
+ return l;
+ msleep(TPM_TIMEOUT);
+ }
+ while (time_before(jiffies, stop));
+ }
+ return -1;
+}
+
+static u8 tpm_tis_status(struct tpm_chip *chip)
+{
+ return ioread8(chip->vendor.iobase +
+ TPM_STS(chip->vendor.locality));
+}
+
+static void tpm_tis_ready(struct tpm_chip *chip)
+{
+ /* this causes the current command to be aborted */
+ iowrite8(TPM_STS_COMMAND_READY,
+ chip->vendor.iobase + TPM_STS(chip->vendor.locality));
+}
+
+static int get_burstcount(struct tpm_chip *chip)
+{
+ unsigned long stop;
+ int burstcnt;
+
+ /* wait for burstcount */
+ /* which timeout value, spec has 2 answers (c & d) */
+ stop = jiffies + (HZ * chip->vendor.timeout_d / 1000);
+ do {
+ burstcnt = ioread8(chip->vendor.iobase +
+ TPM_STS(chip->vendor.locality) + 1);
+ burstcnt += ioread8(chip->vendor.iobase +
+ TPM_STS(chip->vendor.locality) +
+ 2) << 8;
+ if (burstcnt)
+ return burstcnt;
+ msleep(TPM_TIMEOUT);
+ } while (time_before(jiffies, stop));
+ return -EBUSY;
+}
+
+static int wait_for_stat(struct tpm_chip *chip, u8 mask, u32 timeout,
+ wait_queue_head_t *queue)
+{
+ unsigned long stop;
+ long rc;
+ u8 status;
+
+ /* check current status */
+ status = tpm_tis_status(chip);
+ if ((status & mask) == mask)
+ return 0;
+
+ if (chip->vendor.irq) {
+ rc = wait_event_interruptible_timeout(*queue,
+ ((tpm_tis_status
+ (chip) & mask) ==
+ mask),
+ msecs_to_jiffies
+ (timeout));
+ if (rc > 0)
+ return 0;
+ } else {
+ stop = jiffies + (HZ * timeout / 1000);
+ do {
+ msleep(TPM_TIMEOUT);
+ status = tpm_tis_status(chip);
+ if ((status & mask) == mask)
+ return 0;
+ } while (time_before(jiffies, stop));
+ }
+ return -ETIME;
+}
+
+static int recv_data(struct tpm_chip *chip, u8 * buf, size_t count)
+{
+ int size = 0, burstcnt;
+ while (size < count &&
+ wait_for_stat(chip,
+ TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ chip->vendor.timeout_c,
+ &chip->vendor.read_queue)
+ == 0) {
+ burstcnt = get_burstcount(chip);
+ for (; burstcnt > 0 && size < count; burstcnt--)
+ buf[size++] = ioread8(chip->vendor.iobase +
+ TPM_DATA_FIFO(chip->vendor.
+ locality));
+ }
+ return size;
+}
+
+static int tpm_tis_recv(struct tpm_chip *chip, u8 * buf, size_t count)
+{
+ int size = 0;
+ int expected, status;
+
+ if (count < TPM_HEADER_SIZE) {
+ size = -EIO;
+ goto out;
+ }
+
+ /* read first 10 bytes, including tag, paramsize, and result */
+ if ((size =
+ recv_data(chip, buf, TPM_HEADER_SIZE)) < TPM_HEADER_SIZE) {
+ dev_err(chip->dev, "Unable to read header\n");
+ goto out;
+ }
+
+ expected = be32_to_cpu(*(__be32 *) (buf + 2));
+ if (expected > count) {
+ size = -EIO;
+ goto out;
+ }
+
+ if ((size +=
+ recv_data(chip, &buf[TPM_HEADER_SIZE],
+ expected - TPM_HEADER_SIZE)) < expected) {
+ dev_err(chip->dev, "Unable to read remainder of result\n");
+ size = -ETIME;
+ goto out;
+ }
+
+ wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
+ &chip->vendor.int_queue);
+ status = tpm_tis_status(chip);
+ if (status & TPM_STS_DATA_AVAIL) { /* retry? */
+ dev_err(chip->dev, "Error left over data\n");
+ size = -EIO;
+ goto out;
+ }
+
+out:
+ tpm_tis_ready(chip);
+ release_locality(chip, chip->vendor.locality, 0);
+ return size;
+}
+
+/*
+ * If interrupts are used (signaled by an irq set in the vendor structure)
+ * tpm.c can skip polling for the data to be available as the interrupt is
+ * waited for here
+ */
+static int tpm_tis_send(struct tpm_chip *chip, u8 * buf, size_t len)
+{
+ int rc, status, burstcnt;
+ size_t count = 0;
+ u32 ordinal;
+
+ if (request_locality(chip, 0) < 0)
+ return -EBUSY;
+
+ status = tpm_tis_status(chip);
+ if ((status & TPM_STS_COMMAND_READY) == 0) {
+ tpm_tis_ready(chip);
+ if (wait_for_stat
+ (chip, TPM_STS_COMMAND_READY, chip->vendor.timeout_b,
+ &chip->vendor.int_queue) < 0) {
+ rc = -ETIME;
+ goto out_err;
+ }
+ }
+
+ while (count < len - 1) {
+ burstcnt = get_burstcount(chip);
+ for (; burstcnt > 0 && count < len - 1; burstcnt--) {
+ iowrite8(buf[count], chip->vendor.iobase +
+ TPM_DATA_FIFO(chip->vendor.locality));
+ count++;
+ }
+
+ wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
+ &chip->vendor.int_queue);
+ status = tpm_tis_status(chip);
+ if ((status & TPM_STS_DATA_EXPECT) == 0) {
+ rc = -EIO;
+ goto out_err;
+ }
+ }
+
+ /* write last byte */
+ iowrite8(buf[count],
+ chip->vendor.iobase +
+ TPM_DATA_FIFO(chip->vendor.locality));
+ wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
+ &chip->vendor.int_queue);
+ status = tpm_tis_status(chip);
+ if ((status & TPM_STS_DATA_EXPECT) != 0) {
+ rc = -EIO;
+ goto out_err;
+ }
+
+ /* go and do it */
+ iowrite8(TPM_STS_GO,
+ chip->vendor.iobase + TPM_STS(chip->vendor.locality));
+
+ if (chip->vendor.irq) {
+ ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
+ if (wait_for_stat
+ (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ tpm_calc_ordinal_duration(chip, ordinal),
+ &chip->vendor.read_queue) < 0) {
+ rc = -ETIME;
+ goto out_err;
+ }
+ }
+ return len;
+out_err:
+ tpm_tis_ready(chip);
+ release_locality(chip, chip->vendor.locality, 0);
+ return rc;
+}
+
+static struct file_operations tis_ops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .open = tpm_open,
+ .read = tpm_read,
+ .write = tpm_write,
+ .release = tpm_release,
+};
+
+static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
+static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
+static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
+static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
+static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
+static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated,
+ NULL);
+static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps_1_2, NULL);
+static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
+
+static struct attribute *tis_attrs[] = {
+ &dev_attr_pubek.attr,
+ &dev_attr_pcrs.attr,
+ &dev_attr_enabled.attr,
+ &dev_attr_active.attr,
+ &dev_attr_owned.attr,
+ &dev_attr_temp_deactivated.attr,
+ &dev_attr_caps.attr,
+ &dev_attr_cancel.attr, NULL,
+};
+
+static struct attribute_group tis_attr_grp = {
+ .attrs = tis_attrs
+};
+
+static struct tpm_vendor_specific tpm_tis = {
+ .status = tpm_tis_status,
+ .recv = tpm_tis_recv,
+ .send = tpm_tis_send,
+ .cancel = tpm_tis_ready,
+ .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ .req_canceled = TPM_STS_COMMAND_READY,
+ .attr_group = &tis_attr_grp,
+ .miscdev = {
+ .fops = &tis_ops,},
+};
+
+static irqreturn_t tis_int_probe(int irq, void *dev_id, struct pt_regs
+ *regs)
+{
+ struct tpm_chip *chip = (struct tpm_chip *) dev_id;
+ u32 interrupt;
+
+ interrupt = ioread32(chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality));
+
+ if (interrupt == 0)
+ return IRQ_NONE;
+
+ chip->vendor.irq = irq;
+
+ /* Clear interrupts handled with TPM_EOI */
+ iowrite32(interrupt,
+ chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality));
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t tis_int_handler(int irq, void *dev_id, struct pt_regs
+ *regs)
+{
+ struct tpm_chip *chip = (struct tpm_chip *) dev_id;
+ u32 interrupt;
+ int i;
+
+ interrupt = ioread32(chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality));
+
+ if (interrupt == 0)
+ return IRQ_NONE;
+
+ if (interrupt & TPM_INTF_DATA_AVAIL_INT)
+ wake_up_interruptible(&chip->vendor.read_queue);
+ if (interrupt & TPM_INTF_LOCALITY_CHANGE_INT)
+ for (i = 0; i < 5; i++)
+ if (check_locality(chip, i) >= 0)
+ break;
+ if (interrupt &
+ (TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_STS_VALID_INT |
+ TPM_INTF_CMD_READY_INT))
+ wake_up_interruptible(&chip->vendor.int_queue);
+
+ /* Clear interrupts handled with TPM_EOI */
+ iowrite32(interrupt,
+ chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality));
+ return IRQ_HANDLED;
+}
+
+static int __devinit tpm_tis_pnp_init(struct pnp_dev
+ *pnp_dev, const struct
+ pnp_device_id
+ *pnp_id)
+{
+ u32 vendor, intfcaps, intmask;
+ int rc, i;
+ unsigned long start, len;
+ struct tpm_chip *chip;
+
+ start = pnp_mem_start(pnp_dev, 0);
+ len = pnp_mem_len(pnp_dev, 0);
+
+ if (!(chip = tpm_register_hardware(&pnp_dev->dev, &tpm_tis)))
+ return -ENODEV;
+
+ chip->vendor.iobase = ioremap(start, len);
+ if (!chip->vendor.iobase) {
+ rc = -EIO;
+ goto out_err;
+ }
+
+ vendor = ioread32(chip->vendor.iobase + TPM_DID_VID(0));
+ if ((vendor & 0xFFFF) == 0xFFFF) {
+ rc = -ENODEV;
+ goto out_err;
+ }
+
+ /* Default timeouts */
+ chip->vendor.timeout_a = 750; /* ms */
+ chip->vendor.timeout_b = 2000; /* 2 sec */
+ chip->vendor.timeout_c = 750; /* ms */
+ chip->vendor.timeout_d = 750; /* ms */
+
+ dev_info(&pnp_dev->dev,
+ "1.2 TPM (device-id 0x%X, rev-id %d)\n",
+ vendor >> 16, ioread8(chip->vendor.iobase + TPM_RID(0)));
+
+ /* Figure out the capabilities */
+ intfcaps =
+ ioread32(chip->vendor.iobase +
+ TPM_INTF_CAPS(chip->vendor.locality));
+ dev_dbg(&pnp_dev->dev, "TPM interface capabilities (0x%x):\n",
+ intfcaps);
+ if (intfcaps & TPM_INTF_BURST_COUNT_STATIC)
+ dev_dbg(&pnp_dev->dev, "\tBurst Count Static\n");
+ if (intfcaps & TPM_INTF_CMD_READY_INT)
+ dev_dbg(&pnp_dev->dev, "\tCommand Ready Int Support\n");
+ if (intfcaps & TPM_INTF_INT_EDGE_FALLING)
+ dev_dbg(&pnp_dev->dev, "\tInterrupt Edge Falling\n");
+ if (intfcaps & TPM_INTF_INT_EDGE_RISING)
+ dev_dbg(&pnp_dev->dev, "\tInterrupt Edge Rising\n");
+ if (intfcaps & TPM_INTF_INT_LEVEL_LOW)
+ dev_dbg(&pnp_dev->dev, "\tInterrupt Level Low\n");
+ if (intfcaps & TPM_INTF_INT_LEVEL_HIGH)
+ dev_dbg(&pnp_dev->dev, "\tInterrupt Level High\n");
+ if (intfcaps & TPM_INTF_LOCALITY_CHANGE_INT)
+ dev_dbg(&pnp_dev->dev, "\tLocality Change Int Support\n");
+ if (intfcaps & TPM_INTF_STS_VALID_INT)
+ dev_dbg(&pnp_dev->dev, "\tSts Valid Int Support\n");
+ if (intfcaps & TPM_INTF_DATA_AVAIL_INT)
+ dev_dbg(&pnp_dev->dev, "\tData Avail Int Support\n");
+
+ if (request_locality(chip, 0) != 0) {
+ rc = -ENODEV;
+ goto out_err;
+ }
+
+ /* INTERRUPT Setup */
+ init_waitqueue_head(&chip->vendor.read_queue);
+ init_waitqueue_head(&chip->vendor.int_queue);
+
+ intmask =
+ ioread32(chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+
+ intmask |= TPM_INTF_CMD_READY_INT
+ | TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_DATA_AVAIL_INT
+ | TPM_INTF_STS_VALID_INT;
+
+ iowrite32(intmask,
+ chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+
+ chip->vendor.irq =
+ ioread8(chip->vendor.iobase +
+ TPM_INT_VECTOR(chip->vendor.locality));
+
+ for (i = 3; i < 16 && chip->vendor.irq == 0; i++) {
+ iowrite8(i,
+ chip->vendor.iobase +
+ TPM_INT_VECTOR(chip->vendor.locality));
+ if (request_irq
+ (i, tis_int_probe, SA_SHIRQ,
+ chip->vendor.miscdev.name, chip) != 0) {
+ dev_info(chip->dev,
+ "Unable to request irq: %d for probe\n",
+ i);
+ continue;
+ }
+
+ /* Clear all existing */
+ iowrite32(ioread32
+ (chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality)),
+ chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality));
+
+ /* Turn on */
+ iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
+ chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+
+ /* Generate Interrupts */
+ tpm_gen_interrupt(chip);
+
+ /* Turn off */
+ iowrite32(intmask,
+ chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+ free_irq(i, chip);
+ }
+ if (chip->vendor.irq) {
+ iowrite8(chip->vendor.irq,
+ chip->vendor.iobase +
+ TPM_INT_VECTOR(chip->vendor.locality));
+ if (request_irq
+ (chip->vendor.irq, tis_int_handler, SA_SHIRQ,
+ chip->vendor.miscdev.name, chip) != 0) {
+ dev_info(chip->dev,
+ "Unable to request irq: %d for use\n", i);
+ chip->vendor.irq = 0;
+ } else {
+ /* Clear all existing */
+ iowrite32(ioread32
+ (chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality)),
+ chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality));
+
+ /* Turn on */
+ iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
+ chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+ }
+ }
+
+ INIT_LIST_HEAD(&chip->vendor.list);
+ spin_lock(&tis_lock);
+ list_add(&chip->vendor.list, &tis_chips);
+ spin_unlock(&tis_lock);
+
+ tpm_get_timeouts(chip);
+ tpm_continue_selftest(chip);
+
+ return 0;
+out_err:
+ if (chip->vendor.iobase)
+ iounmap(chip->vendor.iobase);
+ tpm_remove_hardware(chip->dev);
+ return rc;
+}
+
+static int tpm_tis_pnp_suspend(struct pnp_dev *dev, pm_message_t msg)
+{
+ return tpm_pm_suspend(&dev->dev, msg);
+}
+
+static int tpm_tis_pnp_resume(struct pnp_dev *dev)
+{
+ return tpm_pm_resume(&dev->dev);
+}
+
+static struct pnp_device_id tpm_pnp_tbl[] __devinitdata = {
+ {"PNP0C31", 0}, /* TPM */
+ {"", 0}
+};
+
+static struct pnp_driver tis_pnp_driver = {
+ .name = "tpm_tis",
+ .id_table = tpm_pnp_tbl,
+ .probe = tpm_tis_pnp_init,
+ .suspend = tpm_tis_pnp_suspend,
+ .resume = tpm_tis_pnp_resume,
+};
+
+static int __init init_tis(void)
+{
+ return pnp_register_driver(&tis_pnp_driver);
+}
+
+static void __exit cleanup_tis(void)
+{
+ struct tpm_vendor_specific *i, *j;
+ struct tpm_chip *chip;
+ spin_lock(&tis_lock);
+ list_for_each_entry_safe(i, j, &tis_chips, list) {
+ chip = to_tpm_chip(i);
+ iowrite32(~TPM_GLOBAL_INT_ENABLE &
+ ioread32(chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.
+ locality)),
+ chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+ release_locality(chip, chip->vendor.locality, 1);
+ if (chip->vendor.irq)
+ free_irq(chip->vendor.irq, chip);
+ iounmap(i->iobase);
+ list_del(&i->list);
+ tpm_remove_hardware(chip->dev);
+ }
+ spin_unlock(&tis_lock);
+ pnp_unregister_driver(&tis_pnp_driver);
+}
+
+module_init(init_tis);
+module_exit(cleanup_tis);
+MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
+MODULE_DESCRIPTION("TPM Driver");
+MODULE_VERSION("2.0");
+MODULE_LICENSE("GPL");
projects / linux-2.6 / commitdiff