me_common.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <device/mmio.h>
#include <device/device.h>
#include <device/pci.h>
#include <device/pci_ops.h>
#include <console/console.h>
#include <device/pci_ids.h>
#include <device/pci_def.h>
#include <string.h>
#include <delay.h>
#include <halt.h>
#include <timer.h>
 
#include "me.h"
#include "pch.h"
 
#include <vendorcode/google/chromeos/chromeos.h>
 
/* Path that the BIOS should take based on ME state */
static const char *const me_bios_path_values[] = {
        [ME_NORMAL_BIOS_PATH]           = "Normal",
        [ME_S3WAKE_BIOS_PATH]           = "S3 Wake",
        [ME_ERROR_BIOS_PATH]            = "Error",
        [ME_RECOVERY_BIOS_PATH]         = "Recovery",
        [ME_DISABLE_BIOS_PATH]          = "Disable",
        [ME_FIRMWARE_UPDATE_BIOS_PATH]  = "Firmware Update",
};
 
const char *const me_get_bios_path_string(int path)
{
        return me_bios_path_values[path];
}
 
/* MMIO base address for MEI interface */
static u32 *mei_base_address;
 
static void mei_dump(void *ptr, int dword, int offset, const char *type)
{
        struct mei_csr *csr;
 
        if (!CONFIG(DEBUG_INTEL_ME))
                return;
 
        printk(BIOS_SPEW, "%-9s[%02x] : ", type, offset);
 
        switch (offset) {
        case MEI_H_CSR:
        case MEI_ME_CSR_HA:
                csr = ptr;
                if (!csr) {
                        printk(BIOS_SPEW, "ERROR: 0x%08x\n", dword);
                        break;
                }
                printk(BIOS_SPEW, "cbd=%u cbrp=%02u cbwp=%02u ready=%u "
                       "reset=%u ig=%u is=%u ie=%u\n", csr->buffer_depth,
                       csr->buffer_read_ptr, csr->buffer_write_ptr,
                       csr->ready, csr->reset, csr->interrupt_generate,
                       csr->interrupt_status, csr->interrupt_enable);
                break;
        case MEI_ME_CB_RW:
        case MEI_H_CB_WW:
                printk(BIOS_SPEW, "CB: 0x%08x\n", dword);
                break;
        default:
                printk(BIOS_SPEW, "0x%08x\n", offset);
                break;
        }
}
 
/*
 * ME/MEI access helpers using memcpy to avoid aliasing.
 */
 
void mei_read_dword_ptr(void *ptr, int offset)
{
        u32 dword = read32(mei_base_address + (offset / sizeof(u32)));
        memcpy(ptr, &dword, sizeof(dword));
        mei_dump(ptr, dword, offset, "READ");
}
 
void mei_write_dword_ptr(void *ptr, int offset)
{
        u32 dword = 0;
        memcpy(&dword, ptr, sizeof(dword));
        write32(mei_base_address + (offset / sizeof(u32)), dword);
        mei_dump(ptr, dword, offset, "WRITE");
}
 
void read_host_csr(struct mei_csr *csr)
{
        mei_read_dword_ptr(csr, MEI_H_CSR);
}
 
void write_host_csr(struct mei_csr *csr)
{
        mei_write_dword_ptr(csr, MEI_H_CSR);
}
 
void read_me_csr(struct mei_csr *csr)
{
        mei_read_dword_ptr(csr, MEI_ME_CSR_HA);
}
 
void write_cb(u32 dword)
{
        write32(mei_base_address + (MEI_H_CB_WW / sizeof(u32)), dword);
        mei_dump(NULL, dword, MEI_H_CB_WW, "WRITE");
}
 
u32 read_cb(void)
{
        u32 dword = read32(mei_base_address + (MEI_ME_CB_RW / sizeof(u32)));
        mei_dump(NULL, dword, MEI_ME_CB_RW, "READ");
        return dword;
}
 
/* Wait for ME ready bit to be asserted */
static int mei_wait_for_me_ready(void)
{
        struct mei_csr me;
        unsigned int try = ME_RETRY;
 
        while (try--) {
                read_me_csr(&me);
                if (me.ready)
                        return 0;
                udelay(ME_DELAY);
        }
 
        printk(BIOS_ERR, "ME: failed to become ready\n");
        return -1;
}
 
static void mei_reset(void)
{
        struct mei_csr host;
 
        if (mei_wait_for_me_ready() < 0)
                return;
 
        /* Reset host and ME circular buffers for next message */
        read_host_csr(&host);
        host.reset = 1;
        host.interrupt_generate = 1;
        write_host_csr(&host);
 
        if (mei_wait_for_me_ready() < 0)
                return;
 
        /* Re-init and indicate host is ready */
        read_host_csr(&host);
        host.interrupt_generate = 1;
        host.ready = 1;
        host.reset = 0;
        write_host_csr(&host);
}
 
static int mei_send_msg(struct mei_header *mei, struct mkhi_header *mkhi, void *req_data)
{
        struct mei_csr host;
        unsigned int ndata, n;
        u32 *data;
 
        /* Number of dwords to write, ignoring MKHI */
        ndata = mei->length >> 2;
 
        /* Pad non-dword aligned request message length */
        if (mei->length & 3)
                ndata++;
 
        if (!ndata) {
                printk(BIOS_DEBUG, "ME: request does not include MKHI\n");
                return -1;
        }
        ndata++; /* Add MEI header */
 
        /*
         * Make sure there is still room left in the circular buffer.
         * Reset the buffer pointers if the requested message will not fit.
         */
        read_host_csr(&host);
        if ((host.buffer_depth - host.buffer_write_ptr) < ndata) {
                printk(BIOS_ERR, "ME: circular buffer full, resetting...\n");
                mei_reset();
                read_host_csr(&host);
        }
 
        /*
         * This implementation does not handle splitting large messages
         * across multiple transactions.  Ensure the requested length
         * will fit in the available circular buffer depth.
         */
        if ((host.buffer_depth - host.buffer_write_ptr) < ndata) {
                printk(BIOS_ERR, "ME: message (%u) too large for buffer (%u)\n",
                       ndata + 2, host.buffer_depth);
                return -1;
        }
 
        /* Write MEI header */
        mei_write_dword_ptr(mei, MEI_H_CB_WW);
        ndata--;
 
        /* Write MKHI header */
        mei_write_dword_ptr(mkhi, MEI_H_CB_WW);
        ndata--;
 
        /* Write message data */
        data = req_data;
        for (n = 0; n < ndata; ++n)
                write_cb(*data++);
 
        /* Generate interrupt to the ME */
        read_host_csr(&host);
        host.interrupt_generate = 1;
        write_host_csr(&host);
 
        /* Make sure ME is ready after sending request data */
        return mei_wait_for_me_ready();
}
 
static int mei_recv_msg(struct mkhi_header *mkhi, void *rsp_data, int rsp_bytes)
{
        struct mei_header mei_rsp;
        struct mkhi_header mkhi_rsp;
        struct mei_csr me, host;
        unsigned int ndata, n;
        unsigned int expected;
        u32 *data;
 
        /* Total number of dwords to read from circular buffer */
        expected = (rsp_bytes + sizeof(mei_rsp) + sizeof(mkhi_rsp)) >> 2;
        if (rsp_bytes & 3)
                expected++;
 
        /*
         * The interrupt status bit does not appear to indicate that the
         * message has actually been received.  Instead we wait until the
         * expected number of dwords are present in the circular buffer.
         */
        for (n = ME_RETRY; n; --n) {
                read_me_csr(&me);
                if ((me.buffer_write_ptr - me.buffer_read_ptr) >= expected)
                        break;
                udelay(ME_DELAY);
        }
 
        if (!n) {
                printk(BIOS_ERR, "ME: timeout waiting for data: expected %u, available %u\n",
                       expected, me.buffer_write_ptr - me.buffer_read_ptr);
                return -1;
        }
 
        /* Read and verify MEI response header from the ME */
        mei_read_dword_ptr(&mei_rsp, MEI_ME_CB_RW);
        if (!mei_rsp.is_complete) {
                printk(BIOS_ERR, "ME: response is not complete\n");
                return -1;
        }
 
        /* Handle non-dword responses and expect at least MKHI header */
        ndata = mei_rsp.length >> 2;
        if (mei_rsp.length & 3)
                ndata++;
 
        if (ndata != (expected - 1)) {
                printk(BIOS_ERR, "ME: response is missing data %d != %d\n",
                       ndata, (expected - 1));
                return -1;
        }
 
        /* Read and verify MKHI response header from the ME */
        mei_read_dword_ptr(&mkhi_rsp, MEI_ME_CB_RW);
        if (!mkhi_rsp.is_response ||
            mkhi->group_id != mkhi_rsp.group_id ||
            mkhi->command != mkhi_rsp.command) {
                printk(BIOS_ERR, "ME: invalid response, group %u ?= %u, "
                       "command %u ?= %u, is_response %u\n", mkhi->group_id,
                       mkhi_rsp.group_id, mkhi->command, mkhi_rsp.command,
                       mkhi_rsp.is_response);
                return -1;
        }
        ndata--; /* MKHI header has been read */
 
        /* Make sure caller passed a buffer with enough space */
        if (ndata != (rsp_bytes >> 2)) {
                printk(BIOS_ERR, "ME: not enough room in response buffer: %u != %u\n",
                       ndata, rsp_bytes >> 2);
                return -1;
        }
 
        /* Read response data from the circular buffer */
        data = rsp_data;
        for (n = 0; n < ndata; ++n)
                *data++ = read_cb();
 
        /* Tell the ME that we have consumed the response */
        read_host_csr(&host);
        host.interrupt_status = 1;
        host.interrupt_generate = 1;
        write_host_csr(&host);
 
        return mei_wait_for_me_ready();
}
 
int mei_sendrecv(struct mei_header *mei, struct mkhi_header *mkhi,
                 void *req_data, void *rsp_data, int rsp_bytes)
{
        if (mei_send_msg(mei, mkhi, req_data) < 0)
                return -1;
        if (mei_recv_msg(mkhi, rsp_data, rsp_bytes) < 0)
                return -1;
        return 0;
}
 
#ifdef __SIMPLE_DEVICE__
 
void update_mei_base_address(void)
{
        uint32_t reg32 = pci_read_config32(PCH_ME_DEV, PCI_BASE_ADDRESS_0) & ~0xf;
        mei_base_address = (u32 *)(uintptr_t)reg32;
}
 
bool is_mei_base_address_valid(void)
{
        return mei_base_address && mei_base_address != (u32 *)0xfffffff0;
}
 
#else
 
/* Prepare ME for MEI messages */
int intel_mei_setup(struct device *dev)
{
        struct resource *res;
        struct mei_csr host;
 
        /* Find the MMIO base for the ME interface */
        res = probe_resource(dev, PCI_BASE_ADDRESS_0);
        if (!res || res->base == 0 || res->size == 0) {
                printk(BIOS_DEBUG, "ME: MEI resource not present!\n");
                return -1;
        }
        mei_base_address = (u32 *)(uintptr_t)res->base;
 
        /* Ensure Memory and Bus Master bits are set */
        pci_or_config16(dev, PCI_COMMAND, PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
 
        /* Clean up status for next message */
        read_host_csr(&host);
        host.interrupt_generate = 1;
        host.ready = 1;
        host.reset = 0;
        write_host_csr(&host);
 
        return 0;
}
 
/* Read the Extend register hash of ME firmware */
int intel_me_extend_valid(struct device *dev)
{
        union me_heres status;
        u32 extend[8] = {0};
        int i, count = 0;
 
        status.raw = pci_read_config32(dev, PCI_ME_HERES);
        if (!status.extend_feature_present) {
                printk(BIOS_ERR, "ME: Extend Feature not present\n");
                return -1;
        }
 
        if (!status.extend_reg_valid) {
                printk(BIOS_ERR, "ME: Extend Register not valid\n");
                return -1;
        }
 
        switch (status.extend_reg_algorithm) {
        case PCI_ME_EXT_SHA1:
                count = 5;
                printk(BIOS_DEBUG, "ME: Extend SHA-1: ");
                break;
        case PCI_ME_EXT_SHA256:
                count = 8;
                printk(BIOS_DEBUG, "ME: Extend SHA-256: ");
                break;
        default:
                printk(BIOS_ERR, "ME: Extend Algorithm %d unknown\n",
                       status.extend_reg_algorithm);
                return -1;
        }
 
        for (i = 0; i < count; ++i) {
                extend[i] = pci_read_config32(dev, PCI_ME_HER(i));
                printk(BIOS_DEBUG, "%08x", extend[i]);
        }
        printk(BIOS_DEBUG, "\n");
 
        /* Save hash in NVS for the OS to verify */
        if (CONFIG(CHROMEOS_NVS))
                chromeos_set_me_hash(extend, count);
 
        return 0;
}
 
/* Hide the ME virtual PCI devices */
void intel_me_hide(struct device *dev)
{
        dev->enabled = 0;
        pch_enable(dev);
}
 
bool enter_soft_temp_disable(void)
{
        /* The binary sequence for the disable command was found by PT in some vendor BIOS */
        struct me_disable message = {
                .rule_id = MKHI_DISABLE_RULE_ID,
                .data = 0x01,
        };
        struct mkhi_header mkhi = {
                .group_id       = MKHI_GROUP_ID_FWCAPS,
                .command        = MKHI_FWCAPS_SET_RULE,
        };
        struct mei_header mei = {
                .is_complete    = 1,
                .length         = sizeof(mkhi) + sizeof(message),
                .host_address   = MEI_HOST_ADDRESS,
                .client_address = MEI_ADDRESS_MKHI,
        };
        u32 resp;
 
        if (mei_sendrecv(&mei, &mkhi, &message, &resp, sizeof(resp)) < 0
            || resp != MKHI_DISABLE_RULE_ID) {
                printk(BIOS_WARNING, "ME: disable command failed\n");
                return false;
        }
 
        return true;
}
 
void enter_soft_temp_disable_wait(void)
{
        /*
         * TODO: Find smarter way to determine when we're ready to reboot.
         *
         * There has to be some bit in some register, or something, that indicates that ME has
         * finished doing its thing and we're ready to reboot.
         *
         * It was not found yet, though, and waiting for a response after the disable command is
         * not enough. If we reboot too early, ME will not be disabled on next boot. For now,
         * let's just wait for 1 second here.
         */
        mdelay(1000);
}
 
void exit_soft_temp_disable(struct device *dev)
{
        /* To bring ME out of Soft Temporary Disable Mode, host writes 0x20000000 to H_GS */
        pci_write_config32(dev, PCI_ME_H_GS, 0x2 << 28);
}
 
void exit_soft_temp_disable_wait(struct device *dev)
{
        union me_hfs hfs;
        struct stopwatch sw;
 
        stopwatch_init_msecs_expire(&sw, ME_ENABLE_TIMEOUT);
 
        /**
         * Wait for fw_init_complete. Check every 50 ms, give up after 20 sec.
         * This is what vendor BIOS does. Usually it takes 1.5 seconds or so.
         */
        do {
                mdelay(50);
                hfs.raw = pci_read_config32(dev, PCI_ME_HFS);
                if (hfs.fw_init_complete)
                        break;
        } while (!stopwatch_expired(&sw));
 
        if (!hfs.fw_init_complete)
                printk(BIOS_ERR, "ME: giving up on waiting for fw_init_complete\n");
        else
                printk(BIOS_NOTICE, "ME: took %lums to complete initialization\n",
                       stopwatch_duration_msecs(&sw));
}
 
#endif