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- // 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 <log.h>
- #include <spl.h>
- #include <tpm-v2.h>
- #include <acpi/acpigen.h>
- #include <acpi/acpi_device.h>
- #include <asm/gpio.h>
- #include <asm/io.h>
- #include <asm/arch/iomap.h>
- #include <asm/arch/pm.h>
- #include <linux/delay.h>
- #include <dm/acpi.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 - Private driver data
- *
- * @ready_gpio: GPIO to use to check if the TPM is ready
- * @irq: IRQ to use check if the TPM is ready (has priority over @ready_gpio)
- * @locality: Currenttly claimed locality (-1 if none)
- * @vendor: vendor: Vendor ID for TPM
- * @use_irq: true to use @irq, false to use @ready if available
- */
- 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 = -1;
- 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;
- struct cr50_priv *priv = dev_get_priv(dev);
- 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);
- priv->locality = 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)
- {
- struct cr50_priv *priv = dev_get_priv(dev);
- printf("%s: cleanup %d\n", __func__, priv->locality);
- if (priv->locality != -1)
- release_locality(dev, 1);
- return 0;
- }
- static int cr50_acpi_fill_ssdt(const struct udevice *dev, struct acpi_ctx *ctx)
- {
- char scope[ACPI_PATH_MAX];
- char name[ACPI_NAME_MAX];
- const char *hid;
- int ret;
- ret = acpi_device_scope(dev, scope, sizeof(scope));
- if (ret)
- return log_msg_ret("scope", ret);
- ret = acpi_get_name(dev, name);
- if (ret)
- return log_msg_ret("name", ret);
- hid = dev_read_string(dev, "acpi,hid");
- if (!hid)
- return log_msg_ret("hid", ret);
- /* Device */
- acpigen_write_scope(ctx, scope);
- acpigen_write_device(ctx, name);
- acpigen_write_name_string(ctx, "_HID", hid);
- acpigen_write_name_integer(ctx, "_UID",
- dev_read_u32_default(dev, "acpi,uid", 0));
- acpigen_write_name_string(ctx, "_DDN",
- dev_read_string(dev, "acpi,ddn"));
- acpigen_write_sta(ctx, acpi_device_status(dev));
- /* Resources */
- acpigen_write_name(ctx, "_CRS");
- acpigen_write_resourcetemplate_header(ctx);
- ret = acpi_device_write_i2c_dev(ctx, dev);
- if (ret < 0)
- return log_msg_ret("i2c", ret);
- ret = acpi_device_write_interrupt_or_gpio(ctx, (struct udevice *)dev,
- "ready-gpios");
- if (ret < 0)
- return log_msg_ret("irq_gpio", ret);
- acpigen_write_resourcetemplate_footer(ctx);
- acpigen_pop_len(ctx); /* Device */
- acpigen_pop_len(ctx); /* Scope */
- 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-gpios", 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;
- priv->locality = -1;
- return 0;
- }
- struct acpi_ops cr50_acpi_ops = {
- .fill_ssdt = cr50_acpi_fill_ssdt,
- };
- 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,
- .remove = cr50_i2c_cleanup,
- .priv_auto_alloc_size = sizeof(struct cr50_priv),
- ACPI_OPS_PTR(&cr50_acpi_ops)
- .flags = DM_FLAG_OS_PREPARE,
- };
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