/* * This file is part of the coreboot project. * * Copyright (C) 2011 The Chromium OS Authors. All rights reserved. * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ /* * The code in this file has been heavily based on the article "Writing a TPM * Device Driver" published on http://ptgmedia.pearsoncmg.com and the * submission by Stefan Berger on Qemu-devel mailing list. * * One principal difference is that in the simplest config the other than 0 * TPM localities do not get mapped by some devices (for instance, by * Infineon slb9635), so this driver provides access to locality 0 only. */ #include <stdlib.h> #include <string.h> #include <delay.h> #include <arch/io.h> #include <console/console.h> #include <tpm.h> #include <arch/early_variables.h> #include <device/pnp.h> #include "chip.h" #define PREFIX "lpc_tpm: " /* coreboot wrapper for TPM driver (start) */ #define TPM_DEBUG(fmt, args...) \ if (IS_ENABLED(CONFIG_DEBUG_TPM)) { \ printk(BIOS_DEBUG, PREFIX); \ printk(BIOS_DEBUG, fmt , ##args); \ } #define TPM_DEBUG_IO_READ(reg_, val_) \ TPM_DEBUG("Read reg 0x%x returns 0x%x\n", (reg_), (val_)) #define TPM_DEBUG_IO_WRITE(reg_, val_) \ TPM_DEBUG("Write reg 0x%x with 0x%x\n", (reg_), (val_)) #define printf(x...) printk(BIOS_ERR, x) /* coreboot wrapper for TPM driver (end) */ /* the macro accepts the locality value, but only locality 0 is operational */ #define TIS_REG(LOCALITY, REG) \ (void *)(CONFIG_TPM_TIS_BASE_ADDRESS + (LOCALITY << 12) + REG) /* hardware registers' offsets */ #define TIS_REG_ACCESS 0x0 #define TIS_REG_INT_ENABLE 0x8 #define TIS_REG_INT_VECTOR 0xc #define TIS_REG_INT_STATUS 0x10 #define TIS_REG_INTF_CAPABILITY 0x14 #define TIS_REG_STS 0x18 #define TIS_REG_BURST_COUNT 0x19 #define TIS_REG_DATA_FIFO 0x24 #define TIS_REG_DID_VID 0xf00 #define TIS_REG_RID 0xf04 /* Some registers' bit field definitions */ #define TIS_STS_VALID (1 << 7) /* 0x80 */ #define TIS_STS_COMMAND_READY (1 << 6) /* 0x40 */ #define TIS_STS_TPM_GO (1 << 5) /* 0x20 */ #define TIS_STS_DATA_AVAILABLE (1 << 4) /* 0x10 */ #define TIS_STS_EXPECT (1 << 3) /* 0x08 */ #define TIS_STS_RESPONSE_RETRY (1 << 1) /* 0x02 */ #define TIS_ACCESS_TPM_REG_VALID_STS (1 << 7) /* 0x80 */ #define TIS_ACCESS_ACTIVE_LOCALITY (1 << 5) /* 0x20 */ #define TIS_ACCESS_BEEN_SEIZED (1 << 4) /* 0x10 */ #define TIS_ACCESS_SEIZE (1 << 3) /* 0x08 */ #define TIS_ACCESS_PENDING_REQUEST (1 << 2) /* 0x04 */ #define TIS_ACCESS_REQUEST_USE (1 << 1) /* 0x02 */ #define TIS_ACCESS_TPM_ESTABLISHMENT (1 << 0) /* 0x01 */ /* * Error value returned if a tpm register does not enter the expected state * after continuous polling. No actual TPM register reading ever returns ~0, * so this value is a safe error indication to be mixed with possible status * register values. */ #define TPM_TIMEOUT_ERR (~0) /* Error value returned on various TPM driver errors */ #define TPM_DRIVER_ERR (~0) /* 1 second is plenty for anything TPM does.*/ #define MAX_DELAY_US (1000 * 1000) /* * Structures defined below allow creating descriptions of TPM vendor/device * ID information for run time discovery. The only device the system knows * about at this time is Infineon slb9635 */ struct device_name { u16 dev_id; const char * const dev_name; }; struct vendor_name { u16 vendor_id; const char * vendor_name; const struct device_name* dev_names; }; static const struct device_name atmel_devices[] = { {0x3204, "AT97SC3204"}, {0xffff} }; static const struct device_name infineon_devices[] = { {0x000b, "SLB9635 TT 1.2"}, {0x001a, "SLB9660 TT 1.2"}, {0x001b, "SLB9670 TT 1.2"}, {0xffff} }; static const struct device_name nuvoton_devices[] = { {0x00fe, "NPCT420AA V2"}, {0xffff} }; static const struct device_name stmicro_devices[] = { {0x0000, "ST33ZP24" }, {0xffff} }; static const struct vendor_name vendor_names[] = { {0x1114, "Atmel", atmel_devices}, {0x15d1, "Infineon", infineon_devices}, {0x1050, "Nuvoton", nuvoton_devices}, {0x104a, "ST Microelectronics", stmicro_devices}, }; /* * Cached vendor/device ID pair to indicate that the device has been already * discovered */ static u32 vendor_dev_id CAR_GLOBAL; static inline u8 tpm_read_status(int locality) { u8 value = read8(TIS_REG(locality, TIS_REG_STS)); TPM_DEBUG_IO_READ(TIS_REG_STS, value); return value; } static inline void tpm_write_status(u8 sts, int locality) { TPM_DEBUG_IO_WRITE(TIS_REG_STS, sts); write8(TIS_REG(locality, TIS_REG_STS), sts); } static inline u8 tpm_read_data(int locality) { u8 value = read8(TIS_REG(locality, TIS_REG_DATA_FIFO)); TPM_DEBUG_IO_READ(TIS_REG_DATA_FIFO, value); return value; } static inline void tpm_write_data(u8 data, int locality) { TPM_DEBUG_IO_WRITE(TIS_REG_STS, data); write8(TIS_REG(locality, TIS_REG_DATA_FIFO), data); } static inline u16 tpm_read_burst_count(int locality) { u16 count; count = read8(TIS_REG(locality, TIS_REG_BURST_COUNT)); count |= read8(TIS_REG(locality, TIS_REG_BURST_COUNT + 1)) << 8; TPM_DEBUG_IO_READ(TIS_REG_BURST_COUNT, count); return count; } static inline u8 tpm_read_access(int locality) { u8 value = read8(TIS_REG(locality, TIS_REG_ACCESS)); TPM_DEBUG_IO_READ(TIS_REG_ACCESS, value); return value; } static inline void tpm_write_access(u8 data, int locality) { TPM_DEBUG_IO_WRITE(TIS_REG_ACCESS, data); write8(TIS_REG(locality, TIS_REG_ACCESS), data); } static inline u32 tpm_read_did_vid(int locality) { u32 value = read32(TIS_REG(locality, TIS_REG_DID_VID)); TPM_DEBUG_IO_READ(TIS_REG_DID_VID, value); return value; } static inline void tpm_write_int_vector(int vector, int locality) { TPM_DEBUG_IO_WRITE(TIS_REG_INT_VECTOR, vector); write8(TIS_REG(locality, TIS_REG_INT_VECTOR), vector & 0xf); } static inline void tpm_write_int_polarity(int polarity, int locality) { /* Set polarity and leave all other bits at 0 */ u32 value = (polarity & 0x3) << 3; TPM_DEBUG_IO_WRITE(TIS_REG_INT_ENABLE, value); write32(TIS_REG(locality, TIS_REG_INT_ENABLE), value); } /* * tis_wait_sts() * * Wait for at least a second for a status to change its state to match the * expected state. Normally the transition happens within microseconds. * * @locality - locality * @mask - bitmask for the bitfield(s) to watch * @expected - value the field(s) are supposed to be set to * * Returns 0 on success or TPM_TIMEOUT_ERR on timeout. */ static int tis_wait_sts(int locality, u8 mask, u8 expected) { u32 time_us = MAX_DELAY_US; while (time_us > 0) { u8 value = tpm_read_status(locality); if ((value & mask) == expected) return 0; udelay(1); /* 1 us */ time_us--; } return TPM_TIMEOUT_ERR; } static inline int tis_wait_ready(int locality) { return tis_wait_sts(locality, TIS_STS_COMMAND_READY, TIS_STS_COMMAND_READY); } static inline int tis_wait_valid(int locality) { return tis_wait_sts(locality, TIS_STS_VALID, TIS_STS_VALID); } static inline int tis_wait_valid_data(int locality) { const u8 has_data = TIS_STS_DATA_AVAILABLE | TIS_STS_VALID; return tis_wait_sts(locality, has_data, has_data); } static inline int tis_has_valid_data(int locality) { const u8 has_data = TIS_STS_DATA_AVAILABLE | TIS_STS_VALID; return (tpm_read_status(locality) & has_data) == has_data; } static inline int tis_expect_data(int locality) { return !!(tpm_read_status(locality) & TIS_STS_EXPECT); } /* * tis_wait_access() * * Wait for at least a second for a access to change its state to match the * expected state. Normally the transition happens within microseconds. * * @locality - locality * @mask - bitmask for the bitfield(s) to watch * @expected - value the field(s) are supposed to be set to * * Returns 0 on success or TPM_TIMEOUT_ERR on timeout. */ static int tis_wait_access(int locality, u8 mask, u8 expected) { u32 time_us = MAX_DELAY_US; while (time_us > 0) { u8 value = tpm_read_access(locality); if ((value & mask) == expected) return 0; udelay(1); /* 1 us */ time_us--; } return TPM_TIMEOUT_ERR; } static inline int tis_wait_dropped_access(int locality) { return tis_wait_access(locality, TIS_ACCESS_ACTIVE_LOCALITY, 0); } static inline int tis_wait_received_access(int locality) { return tis_wait_access(locality, TIS_ACCESS_ACTIVE_LOCALITY, TIS_ACCESS_ACTIVE_LOCALITY); } static inline int tis_has_access(int locality) { return !!(tpm_read_access(locality) & TIS_ACCESS_ACTIVE_LOCALITY); } static inline void tis_request_access(int locality) { tpm_write_access(TIS_ACCESS_REQUEST_USE, locality); } static inline void tis_drop_access(int locality) { tpm_write_access(TIS_ACCESS_ACTIVE_LOCALITY, locality); } /* * PC Client Specific TPM Interface Specification section 11.2.12: * * Software must be prepared to send two writes of a "1" to command ready * field: the first to indicate successful read of all the data, thus * clearing the data from the ReadFIFO and freeing the TPM's resources, * and the second to indicate to the TPM it is about to send a new command. * * In practice not all TPMs behave the same so it is necessary to be * flexible when trying to set command ready. * * Returns 0 on success if the TPM is ready for transactions. * Returns TPM_TIMEOUT_ERR if the command ready bit does not get set. */ static int tis_command_ready(u8 locality) { u32 status; /* 1st attempt to set command ready */ tpm_write_status(TIS_STS_COMMAND_READY, locality); /* Wait for response */ status = tpm_read_status(locality); /* Check if command ready is set yet */ if (status & TIS_STS_COMMAND_READY) return 0; /* 2nd attempt to set command ready */ tpm_write_status(TIS_STS_COMMAND_READY, locality); return tis_wait_ready(locality); } /* * Probe the TPM device and try determining its manufacturer/device name. * * Returns 0 on success (the device is found or was found during an earlier * invocation) or TPM_DRIVER_ERR if the device is not found. */ static u32 tis_probe(void) { const char *device_name = "unknown"; const char *vendor_name = device_name; const struct device_name *dev; u32 didvid; u16 vid, did; int i; if (car_get_var(vendor_dev_id)) return 0; /* Already probed. */ didvid = tpm_read_did_vid(0); if (!didvid || (didvid == 0xffffffff)) { printf("%s: No TPM device found\n", __FUNCTION__); return TPM_DRIVER_ERR; } car_set_var(vendor_dev_id, didvid); vid = didvid & 0xffff; did = (didvid >> 16) & 0xffff; for (i = 0; i < ARRAY_SIZE(vendor_names); i++) { int j = 0; u16 known_did; if (vid == vendor_names[i].vendor_id) { vendor_name = vendor_names[i].vendor_name; } else { continue; } dev = &vendor_names[i].dev_names[j]; while ((known_did = dev->dev_id) != 0xffff) { if (known_did == did) { device_name = dev->dev_name; break; } j++; dev = &vendor_names[i].dev_names[j]; } break; } /* this will have to be converted into debug printout */ printk(BIOS_INFO, "Found TPM %s by %s\n", device_name, vendor_name); return 0; } /* * tis_senddata() * * send the passed in data to the TPM device. * * @data - address of the data to send, byte by byte * @len - length of the data to send * * Returns 0 on success, TPM_DRIVER_ERR on error (in case the device does * not accept the entire command). */ static u32 tis_senddata(const u8 * const data, u32 len) { u32 offset = 0; u16 burst = 0; u32 max_cycles = 0; u8 locality = 0; if (tis_wait_ready(locality)) { printf("%s:%d - failed to get 'command_ready' status\n", __FILE__, __LINE__); return TPM_DRIVER_ERR; } burst = tpm_read_burst_count(locality); while (1) { unsigned count; /* Wait till the device is ready to accept more data. */ while (!burst) { if (max_cycles++ == MAX_DELAY_US) { printf("%s:%d failed to feed %d bytes of %d\n", __FILE__, __LINE__, len - offset, len); return TPM_DRIVER_ERR; } udelay(1); burst = tpm_read_burst_count(locality); } max_cycles = 0; /* * Calculate number of bytes the TPM is ready to accept in one * shot. * * We want to send the last byte outside of the loop (hence * the -1 below) to make sure that the 'expected' status bit * changes to zero exactly after the last byte is fed into the * FIFO. */ count = min(burst, len - offset - 1); while (count--) tpm_write_data(data[offset++], locality); if (tis_wait_valid(locality) || !tis_expect_data(locality)) { printf("%s:%d TPM command feed overflow\n", __FILE__, __LINE__); return TPM_DRIVER_ERR; } burst = tpm_read_burst_count(locality); if ((offset == (len - 1)) && burst) /* * We need to be able to send the last byte to the * device, so burst size must be nonzero before we * break out. */ break; } /* Send the last byte. */ tpm_write_data(data[offset++], locality); /* * Verify that TPM does not expect any more data as part of this * command. */ if (tis_wait_valid(locality) || tis_expect_data(locality)) { printf("%s:%d unexpected TPM status 0x%x\n", __FILE__, __LINE__, tpm_read_status(locality)); return TPM_DRIVER_ERR; } /* OK, sitting pretty, let's start the command execution. */ tpm_write_status(TIS_STS_TPM_GO, locality); return 0; } /* * tis_readresponse() * * read the TPM device response after a command was issued. * * @buffer - address where to read the response, byte by byte. * @len - pointer to the size of buffer * * On success stores the number of received bytes to len and returns 0. On * errors (misformatted TPM data or synchronization problems) returns * TPM_DRIVER_ERR. */ static u32 tis_readresponse(u8 *buffer, size_t *len) { u16 burst_count; u32 offset = 0; u8 locality = 0; u32 expected_count = *len; int max_cycles = 0; /* Wait for the TPM to process the command */ if (tis_wait_valid_data(locality)) { printf("%s:%d failed processing command\n", __FILE__, __LINE__); return TPM_DRIVER_ERR; } do { while ((burst_count = tpm_read_burst_count(locality)) == 0) { if (max_cycles++ == MAX_DELAY_US) { printf("%s:%d TPM stuck on read\n", __FILE__, __LINE__); return TPM_DRIVER_ERR; } udelay(1); } max_cycles = 0; while (burst_count-- && (offset < expected_count)) { buffer[offset++] = tpm_read_data(locality); if (offset == 6) { /* * We got the first six bytes of the reply, * let's figure out how many bytes to expect * total - it is stored as a 4 byte number in * network order, starting with offset 2 into * the body of the reply. */ u32 real_length; memcpy(&real_length, buffer + 2, sizeof(real_length)); expected_count = be32_to_cpu(real_length); if ((expected_count < offset) || (expected_count > *len)) { printf("%s:%d bad response size %d\n", __FILE__, __LINE__, expected_count); return TPM_DRIVER_ERR; } } } /* Wait for the next portion */ if (tis_wait_valid(locality)) { printf("%s:%d failed to read response\n", __FILE__, __LINE__); return TPM_DRIVER_ERR; } if (offset == expected_count) break; /* We got all we need */ } while (tis_has_valid_data(locality)); /* * Make sure we indeed read all there was. */ if (tis_has_valid_data(locality)) { printf("%s:%d wrong receive status: %x %d bytes left\n", __FILE__, __LINE__, tpm_read_status(locality), tpm_read_burst_count(locality)); return TPM_DRIVER_ERR; } /* Tell the TPM that we are done. */ if (tis_command_ready(locality) == TPM_TIMEOUT_ERR) return TPM_DRIVER_ERR; *len = offset; return 0; } /* * tis_init() * * Initialize the TPM device. Returns 0 on success or TPM_DRIVER_ERR on * failure (in case device probing did not succeed). */ int tis_init(void) { if (tis_probe()) return TPM_DRIVER_ERR; return 0; } /* * tis_open() * * Requests access to locality 0 for the caller. After all commands have been * completed the caller is supposed to call tis_close(). * * Returns 0 on success, TPM_DRIVER_ERR on failure. */ int tis_open(void) { u8 locality = 0; /* we use locality zero for everything */ if (tis_close()) return TPM_DRIVER_ERR; /* now request access to locality */ tis_request_access(locality); /* did we get a lock? */ if (tis_wait_received_access(locality)) { printf("%s:%d - failed to lock locality %d\n", __FILE__, __LINE__, locality); return TPM_DRIVER_ERR; } /* Certain TPMs seem to need some delay here or they hang... */ udelay(10); if (tis_command_ready(locality) == TPM_TIMEOUT_ERR) return TPM_DRIVER_ERR; return 0; } /* * tis_close() * * terminate the current session with the TPM by releasing the locked * locality. Returns 0 on success of TPM_DRIVER_ERR on failure (in case lock * removal did not succeed). */ int tis_close(void) { u8 locality = 0; if (tis_has_access(locality)) { tis_drop_access(locality); if (tis_wait_dropped_access(locality)) { printf("%s:%d - failed to release locality %d\n", __FILE__, __LINE__, locality); return TPM_DRIVER_ERR; } } return 0; } /* * tis_sendrecv() * * Send the requested data to the TPM and then try to get its response * * @sendbuf - buffer of the data to send * @send_size size of the data to send * @recvbuf - memory to save the response to * @recv_len - pointer to the size of the response buffer * * Returns 0 on success (and places the number of response bytes at recv_len) * or TPM_DRIVER_ERR on failure. */ int tis_sendrecv(const uint8_t *sendbuf, size_t send_size, uint8_t *recvbuf, size_t *recv_len) { if (tis_senddata(sendbuf, send_size)) { printf("%s:%d failed sending data to TPM\n", __FILE__, __LINE__); return TPM_DRIVER_ERR; } return tis_readresponse(recvbuf, recv_len); } #ifdef __RAMSTAGE__ /* * tis_setup_interrupt() * * Set up the interrupt vector and polarity for locality 0 and * disable all interrupts so they are unused in firmware but can * be enabled by the OS. * * The values used here must match what is passed in the TPM ACPI * device if ACPI is used on the platform. * * @vector - TPM interrupt vector * @polarity - TPM interrupt polarity * * Returns 0 on success, TPM_DRIVER_ERR on failure. */ static int tis_setup_interrupt(int vector, int polarity) { u8 locality = 0; int has_access = tis_has_access(locality); /* Open connection and request access if not already granted */ if (!has_access && tis_open() < 0) return TPM_DRIVER_ERR; /* Set TPM interrupt vector */ tpm_write_int_vector(vector, locality); /* Set TPM interupt polarity and disable interrupts */ tpm_write_int_polarity(polarity, locality); /* Close connection if it was opened */ if (!has_access && tis_close() < 0) return TPM_DRIVER_ERR; return 0; } static void lpc_tpm_read_resources(struct device *dev) { /* Static 5K memory region specified in Kconfig */ mmio_resource(dev, 0, CONFIG_TPM_TIS_BASE_ADDRESS >> 10, 0x5000 >> 10); } static void lpc_tpm_set_resources(struct device *dev) { tpm_config_t *config = (tpm_config_t *)dev->chip_info; struct resource *res; for (res = dev->resource_list; res; res = res->next) { if (!(res->flags & IORESOURCE_ASSIGNED)) continue; if (res->flags & IORESOURCE_IRQ) { /* Set interrupt vector */ tis_setup_interrupt((int)res->base, config->irq_polarity); } else { continue; } res->flags |= IORESOURCE_STORED; report_resource_stored(dev, res, " <tpm>"); } } static struct device_operations lpc_tpm_ops = { .read_resources = &lpc_tpm_read_resources, .set_resources = &lpc_tpm_set_resources, }; static struct pnp_info pnp_dev_info[] = { { .flags = PNP_IRQ0 } }; static void enable_dev(struct device *dev) { pnp_enable_devices(dev, &lpc_tpm_ops, ARRAY_SIZE(pnp_dev_info), pnp_dev_info); } struct chip_operations drivers_pc80_tpm_ops = { CHIP_NAME("LPC TPM") .enable_dev = enable_dev }; #endif /* __RAMSTAGE__ */