--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cr50 / H1 TPM support
+ *
+ * Copyright 2018 Google LLC
+ */
+
+#define LOG_CATEGORY UCLASS_TPM
+
+#include <common.h>
+#include <dm.h>
+#include <i2c.h>
+#include <irq.h>
+#include <spl.h>
+#include <tpm-v2.h>
+#include <asm/gpio.h>
+#include <asm/io.h>
+#include <asm/arch/iomap.h>
+#include <asm/arch/pm.h>
+
+enum {
+ TIMEOUT_INIT_MS = 30000, /* Very long timeout for TPM init */
+ TIMEOUT_LONG_US = 2 * 1000 * 1000,
+ TIMEOUT_SHORT_US = 2 * 1000,
+ TIMEOUT_NO_IRQ_US = 20 * 1000,
+ TIMEOUT_IRQ_US = 100 * 1000,
+};
+
+enum {
+ CR50_DID_VID = 0x00281ae0L
+};
+
+enum {
+ CR50_MAX_BUF_SIZE = 63,
+};
+
+struct cr50_priv {
+ struct gpio_desc ready_gpio;
+ struct irq irq;
+ int locality;
+ uint vendor;
+ bool use_irq;
+};
+
+/* Wait for interrupt to indicate TPM is ready */
+static int cr50_i2c_wait_tpm_ready(struct udevice *dev)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+ ulong timeout, base;
+ int i;
+
+ if (!priv->use_irq && !dm_gpio_is_valid(&priv->ready_gpio)) {
+ /* Fixed delay if interrupt not supported */
+ udelay(TIMEOUT_NO_IRQ_US);
+ return 0;
+ }
+
+ base = timer_get_us();
+ timeout = base + TIMEOUT_IRQ_US;
+
+ i = 0;
+ while (priv->use_irq ? !irq_read_and_clear(&priv->irq) :
+ !dm_gpio_get_value(&priv->ready_gpio)) {
+ i++;
+ if ((int)(timer_get_us() - timeout) >= 0) {
+ log_warning("Timeout\n");
+ /* Use this instead of the -ETIMEDOUT used by i2c */
+ return -ETIME;
+ }
+ }
+ log_debug("i=%d\n", i);
+
+ return 0;
+}
+
+/* Clear pending interrupts */
+static void cr50_i2c_clear_tpm_irq(struct udevice *dev)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+
+ if (priv->use_irq)
+ irq_read_and_clear(&priv->irq);
+}
+
+/*
+ * cr50_i2c_read() - read from TPM register
+ *
+ * @dev: TPM chip information
+ * @addr: register address to read from
+ * @buffer: provided by caller
+ * @len: number of bytes to read
+ *
+ * 1) send register address byte 'addr' to the TPM
+ * 2) wait for TPM to indicate it is ready
+ * 3) read 'len' bytes of TPM response into the provided 'buffer'
+ *
+ * Return 0 on success. -ve on error
+ */
+static int cr50_i2c_read(struct udevice *dev, u8 addr, u8 *buffer,
+ size_t len)
+{
+ int ret;
+
+ /* Clear interrupt before starting transaction */
+ cr50_i2c_clear_tpm_irq(dev);
+
+ /* Send the register address byte to the TPM */
+ ret = dm_i2c_write(dev, 0, &addr, 1);
+ if (ret) {
+ log_err("Address write failed (err=%d)\n", ret);
+ return ret;
+ }
+
+ /* Wait for TPM to be ready with response data */
+ ret = cr50_i2c_wait_tpm_ready(dev);
+ if (ret)
+ return ret;
+
+ /* Read response data frrom the TPM */
+ ret = dm_i2c_read(dev, 0, buffer, len);
+ if (ret) {
+ log_err("Read response failed (err=%d)\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * cr50_i2c_write() - write to TPM register
+ *
+ * @dev: TPM chip information
+ * @addr: register address to write to
+ * @buffer: data to write
+ * @len: number of bytes to write
+ *
+ * 1) prepend the provided address to the provided data
+ * 2) send the address+data to the TPM
+ * 3) wait for TPM to indicate it is done writing
+ *
+ * Returns -1 on error, 0 on success.
+ */
+static int cr50_i2c_write(struct udevice *dev, u8 addr, const u8 *buffer,
+ size_t len)
+{
+ u8 buf[len + 1];
+ int ret;
+
+ if (len > CR50_MAX_BUF_SIZE) {
+ log_err("Length %zd is too large\n", len);
+ return -E2BIG;
+ }
+
+ /* Prepend the 'register address' to the buffer */
+ buf[0] = addr;
+ memcpy(buf + 1, buffer, len);
+
+ /* Clear interrupt before starting transaction */
+ cr50_i2c_clear_tpm_irq(dev);
+
+ /* Send write request buffer with address */
+ ret = dm_i2c_write(dev, 0, buf, len + 1);
+ if (ret) {
+ log_err("Error writing to TPM (err=%d)\n", ret);
+ return ret;
+ }
+
+ /* Wait for TPM to be ready */
+ return cr50_i2c_wait_tpm_ready(dev);
+}
+
+static inline u8 tpm_access(u8 locality)
+{
+ return 0x0 | (locality << 4);
+}
+
+static inline u8 tpm_sts(u8 locality)
+{
+ return 0x1 | (locality << 4);
+}
+
+static inline u8 tpm_data_fifo(u8 locality)
+{
+ return 0x5 | (locality << 4);
+}
+
+static inline u8 tpm_did_vid(u8 locality)
+{
+ return 0x6 | (locality << 4);
+}
+
+static int release_locality(struct udevice *dev, int force)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+ u8 mask = TPM_ACCESS_VALID | TPM_ACCESS_REQUEST_PENDING;
+ u8 addr = tpm_access(priv->locality);
+ int ret;
+ u8 buf;
+
+ ret = cr50_i2c_read(dev, addr, &buf, 1);
+ if (ret)
+ return ret;
+
+ if (force || (buf & mask) == mask) {
+ buf = TPM_ACCESS_ACTIVE_LOCALITY;
+ cr50_i2c_write(dev, addr, &buf, 1);
+ }
+
+ priv->locality = 0;
+
+ return 0;
+}
+
+/* cr50 requires all 4 bytes of status register to be read */
+static int cr50_i2c_status(struct udevice *dev)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+ u8 buf[4];
+ int ret;
+
+ ret = cr50_i2c_read(dev, tpm_sts(priv->locality), buf, sizeof(buf));
+ if (ret) {
+ log_warning("%s: Failed to read status\n", __func__);
+ return ret;
+ }
+
+ return buf[0];
+}
+
+/* cr50 requires all 4 bytes of status register to be written */
+static int cr50_i2c_ready(struct udevice *dev)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+ u8 buf[4] = { TPM_STS_COMMAND_READY };
+ int ret;
+
+ ret = cr50_i2c_write(dev, tpm_sts(priv->locality), buf, sizeof(buf));
+ if (ret)
+ return ret;
+
+ udelay(TIMEOUT_SHORT_US);
+
+ return 0;
+}
+
+static int cr50_i2c_wait_burststs(struct udevice *dev, u8 mask,
+ size_t *burst, int *status)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+ ulong timeout;
+ u32 buf;
+
+ /*
+ * cr50 uses bytes 3:2 of status register for burst count and all 4
+ * bytes must be read
+ */
+ timeout = timer_get_us() + TIMEOUT_LONG_US;
+ while (timer_get_us() < timeout) {
+ if (cr50_i2c_read(dev, tpm_sts(priv->locality),
+ (u8 *)&buf, sizeof(buf)) < 0) {
+ udelay(TIMEOUT_SHORT_US);
+ continue;
+ }
+
+ *status = buf & 0xff;
+ *burst = le16_to_cpu((buf >> 8) & 0xffff);
+
+ if ((*status & mask) == mask &&
+ *burst > 0 && *burst <= CR50_MAX_BUF_SIZE)
+ return 0;
+
+ udelay(TIMEOUT_SHORT_US);
+ }
+
+ log_warning("Timeout reading burst and status\n");
+
+ return -ETIMEDOUT;
+}
+
+static int cr50_i2c_recv(struct udevice *dev, u8 *buf, size_t buf_len)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+ size_t burstcnt, expected, current, len;
+ u8 addr = tpm_data_fifo(priv->locality);
+ u8 mask = TPM_STS_VALID | TPM_STS_DATA_AVAIL;
+ u32 expected_buf;
+ int status;
+ int ret;
+
+ log_debug("%s: len=%x\n", __func__, buf_len);
+ if (buf_len < TPM_HEADER_SIZE)
+ return -E2BIG;
+
+ ret = cr50_i2c_wait_burststs(dev, mask, &burstcnt, &status);
+ if (ret < 0) {
+ log_warning("First chunk not available\n");
+ goto out_err;
+ }
+
+ /* Read first chunk of burstcnt bytes */
+ if (cr50_i2c_read(dev, addr, buf, burstcnt) < 0) {
+ log_warning("Read failed\n");
+ goto out_err;
+ }
+
+ /* Determine expected data in the return buffer */
+ memcpy(&expected_buf, buf + TPM_CMD_COUNT_OFFSET, sizeof(expected_buf));
+ expected = be32_to_cpu(expected_buf);
+ if (expected > buf_len) {
+ log_warning("Too much data: %zu > %zu\n", expected, buf_len);
+ goto out_err;
+ }
+
+ /* Now read the rest of the data */
+ current = burstcnt;
+ while (current < expected) {
+ /* Read updated burst count and check status */
+ if (cr50_i2c_wait_burststs(dev, mask, &burstcnt, &status) < 0) {
+ log_warning("- burst failure1\n");
+ goto out_err;
+ }
+
+ len = min(burstcnt, expected - current);
+ if (cr50_i2c_read(dev, addr, buf + current, len) != 0) {
+ log_warning("Read failed\n");
+ goto out_err;
+ }
+
+ current += len;
+ }
+
+ if (cr50_i2c_wait_burststs(dev, TPM_STS_VALID, &burstcnt,
+ &status) < 0) {
+ log_warning("- burst failure2\n");
+ goto out_err;
+ }
+ if (status & TPM_STS_DATA_AVAIL) {
+ log_warning("Data still available\n");
+ goto out_err;
+ }
+
+ return current;
+
+out_err:
+ /* Abort current transaction if still pending */
+ ret = cr50_i2c_status(dev);
+ if (ret < 0)
+ return ret;
+ if (ret & TPM_STS_COMMAND_READY) {
+ ret = cr50_i2c_ready(dev);
+ if (ret)
+ return ret;
+ }
+
+ return -EIO;
+}
+
+static int cr50_i2c_send(struct udevice *dev, const u8 *buf, size_t len)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+
+ int status;
+ size_t burstcnt, limit, sent = 0;
+ u8 tpm_go[4] = { TPM_STS_GO };
+ ulong timeout;
+ int ret;
+
+ log_debug("%s: len=%x\n", __func__, len);
+ timeout = timer_get_us() + TIMEOUT_LONG_US;
+ do {
+ ret = cr50_i2c_status(dev);
+ if (ret < 0)
+ goto out_err;
+ if (ret & TPM_STS_COMMAND_READY)
+ break;
+
+ if (timer_get_us() > timeout)
+ goto out_err;
+
+ ret = cr50_i2c_ready(dev);
+ if (ret)
+ goto out_err;
+ } while (1);
+
+ while (len > 0) {
+ u8 mask = TPM_STS_VALID;
+
+ /* Wait for data if this is not the first chunk */
+ if (sent > 0)
+ mask |= TPM_STS_DATA_EXPECT;
+
+ if (cr50_i2c_wait_burststs(dev, mask, &burstcnt, &status) < 0)
+ goto out_err;
+
+ /*
+ * Use burstcnt - 1 to account for the address byte
+ * that is inserted by cr50_i2c_write()
+ */
+ limit = min(burstcnt - 1, len);
+ if (cr50_i2c_write(dev, tpm_data_fifo(priv->locality),
+ &buf[sent], limit) != 0) {
+ log_warning("Write failed\n");
+ goto out_err;
+ }
+
+ sent += limit;
+ len -= limit;
+ }
+
+ /* Ensure TPM is not expecting more data */
+ if (cr50_i2c_wait_burststs(dev, TPM_STS_VALID, &burstcnt, &status) < 0)
+ goto out_err;
+ if (status & TPM_STS_DATA_EXPECT) {
+ log_warning("Data still expected\n");
+ goto out_err;
+ }
+
+ /* Start the TPM command */
+ ret = cr50_i2c_write(dev, tpm_sts(priv->locality), tpm_go,
+ sizeof(tpm_go));
+ if (ret) {
+ log_warning("Start command failed\n");
+ goto out_err;
+ }
+
+ return sent;
+
+out_err:
+ /* Abort current transaction if still pending */
+ ret = cr50_i2c_status(dev);
+
+ if (ret < 0 || (ret & TPM_STS_COMMAND_READY)) {
+ ret = cr50_i2c_ready(dev);
+ if (ret)
+ return ret;
+ }
+
+ return -EIO;
+}
+
+/**
+ * process_reset() - Wait for the Cr50 to reset
+ *
+ * Cr50 processes reset requests asynchronously and conceivably could be busy
+ * executing a long command and not reacting to the reset pulse for a while.
+ *
+ * This function will make sure that the AP does not proceed with boot until
+ * TPM finished reset processing.
+ *
+ * @dev: Cr50 device
+ * @return 0 if OK, -EPERM if locality could not be taken
+ */
+static int process_reset(struct udevice *dev)
+{
+ const int loc = 0;
+ u8 access;
+ ulong start;
+
+ /*
+ * Locality is released by TPM reset.
+ *
+ * If locality is taken at this point, this could be due to the fact
+ * that the TPM is performing a long operation and has not processed
+ * reset request yet. We'll wait up to CR50_TIMEOUT_INIT_MS and see if
+ * it releases locality when reset is processed.
+ */
+ start = get_timer(0);
+ do {
+ const u8 mask = TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY;
+ int ret;
+
+ ret = cr50_i2c_read(dev, tpm_access(loc),
+ &access, sizeof(access));
+ if (ret || ((access & mask) == mask)) {
+ /*
+ * Don't bombard the chip with traffic; let it keep
+ * processing the command.
+ */
+ mdelay(2);
+ continue;
+ }
+
+ log_warning("TPM ready after %ld ms\n", get_timer(start));
+
+ return 0;
+ } while (get_timer(start) < TIMEOUT_INIT_MS);
+
+ log_warning("TPM failed to reset after %ld ms, status: %#x\n",
+ get_timer(start), access);
+
+ return -EPERM;
+}
+
+/*
+ * Locality could be already claimed (if this is a later U-Boot phase and the
+ * read-only U-Boot did not release it), or not yet claimed, if this is TPL or
+ * the older read-only U-Boot did release it.
+ */
+static int claim_locality(struct udevice *dev, int loc)
+{
+ const u8 mask = TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY;
+ u8 access;
+ int ret;
+
+ ret = cr50_i2c_read(dev, tpm_access(loc), &access, sizeof(access));
+ if (ret)
+ return log_msg_ret("read1", ret);
+
+ if ((access & mask) == mask) {
+ log_warning("Locality already claimed\n");
+ return 0;
+ }
+
+ access = TPM_ACCESS_REQUEST_USE;
+ ret = cr50_i2c_write(dev, tpm_access(loc), &access, sizeof(access));
+ if (ret)
+ return log_msg_ret("write", ret);
+
+ ret = cr50_i2c_read(dev, tpm_access(loc), &access, sizeof(access));
+ if (ret)
+ return log_msg_ret("read2", ret);
+
+ if ((access & mask) != mask) {
+ log_err("Failed to claim locality\n");
+ return -EPERM;
+ }
+ log_info("Claimed locality %d\n", loc);
+
+ return 0;
+}
+
+static int cr50_i2c_get_desc(struct udevice *dev, char *buf, int size)
+{
+ struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
+ struct cr50_priv *priv = dev_get_priv(dev);
+
+ return snprintf(buf, size, "cr50 TPM 2.0 (i2c %02x id %x) irq=%d",
+ chip->chip_addr, priv->vendor >> 16, priv->use_irq);
+}
+
+static int cr50_i2c_open(struct udevice *dev)
+{
+ char buf[80];
+ int ret;
+
+ ret = process_reset(dev);
+ if (ret)
+ return log_msg_ret("reset", ret);
+
+ ret = claim_locality(dev, 0);
+ if (ret)
+ return log_msg_ret("claim", ret);
+
+ cr50_i2c_get_desc(dev, buf, sizeof(buf));
+ log_debug("%s\n", buf);
+
+ return 0;
+}
+
+static int cr50_i2c_cleanup(struct udevice *dev)
+{
+ release_locality(dev, 1);
+
+ return 0;
+}
+
+enum {
+ TPM_TIMEOUT_MS = 5,
+ SHORT_TIMEOUT_MS = 750,
+ LONG_TIMEOUT_MS = 2000,
+};
+
+static int cr50_i2c_ofdata_to_platdata(struct udevice *dev)
+{
+ struct tpm_chip_priv *upriv = dev_get_uclass_priv(dev);
+ struct cr50_priv *priv = dev_get_priv(dev);
+ struct irq irq;
+ int ret;
+
+ upriv->version = TPM_V2;
+ upriv->duration_ms[TPM_SHORT] = SHORT_TIMEOUT_MS;
+ upriv->duration_ms[TPM_MEDIUM] = LONG_TIMEOUT_MS;
+ upriv->duration_ms[TPM_LONG] = LONG_TIMEOUT_MS;
+ upriv->retry_time_ms = TPM_TIMEOUT_MS;
+
+ upriv->pcr_count = 32;
+ upriv->pcr_select_min = 2;
+
+ /* Optional GPIO to track when cr50 is ready */
+ ret = irq_get_by_index(dev, 0, &irq);
+ if (!ret) {
+ priv->irq = irq;
+ priv->use_irq = true;
+ } else {
+ ret = gpio_request_by_name(dev, "ready-gpio", 0,
+ &priv->ready_gpio, GPIOD_IS_IN);
+ if (ret) {
+ log_warning("Cr50 does not have an ready GPIO/interrupt (err=%d)\n",
+ ret);
+ }
+ }
+
+ return 0;
+}
+
+static int cr50_i2c_probe(struct udevice *dev)
+{
+ struct cr50_priv *priv = dev_get_priv(dev);
+ u32 vendor = 0;
+ ulong start;
+
+ /*
+ * 150ms should be enough to synchronise with the TPM even under the
+ * worst nested-reset-request conditions. In the vast majority of cases
+ * there will be no wait at all.
+ */
+ start = get_timer(0);
+ while (get_timer(start) < 150) {
+ int ret;
+
+ /* Exit once DID and VID verified */
+ ret = cr50_i2c_read(dev, tpm_did_vid(0), (u8 *)&vendor, 4);
+ if (!ret && vendor == CR50_DID_VID)
+ break;
+
+ /* TPM might be resetting; let's retry in a bit */
+ mdelay(10);
+ }
+ if (vendor != CR50_DID_VID) {
+ log_debug("DID_VID %08x not recognised\n", vendor);
+ return log_msg_ret("vendor-id", -EXDEV);
+ }
+ priv->vendor = vendor;
+
+ return 0;
+}
+
+static const struct tpm_ops cr50_i2c_ops = {
+ .open = cr50_i2c_open,
+ .get_desc = cr50_i2c_get_desc,
+ .send = cr50_i2c_send,
+ .recv = cr50_i2c_recv,
+ .cleanup = cr50_i2c_cleanup,
+};
+
+static const struct udevice_id cr50_i2c_ids[] = {
+ { .compatible = "google,cr50" },
+ { }
+};
+
+U_BOOT_DRIVER(cr50_i2c) = {
+ .name = "cr50_i2c",
+ .id = UCLASS_TPM,
+ .of_match = cr50_i2c_ids,
+ .ops = &cr50_i2c_ops,
+ .ofdata_to_platdata = cr50_i2c_ofdata_to_platdata,
+ .probe = cr50_i2c_probe,
+ .priv_auto_alloc_size = sizeof(struct cr50_priv),
+};
projects / oweals / u-boot.git / blobdiff