diff options
Diffstat (limited to 'drivers/crypto/ccp/platform-access.c')
| -rw-r--r-- | drivers/crypto/ccp/platform-access.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/drivers/crypto/ccp/platform-access.c b/drivers/crypto/ccp/platform-access.c new file mode 100644 index 0000000000..94367bc49e --- /dev/null +++ b/drivers/crypto/ccp/platform-access.c @@ -0,0 +1,220 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * AMD Platform Security Processor (PSP) Platform Access interface + * + * Copyright (C) 2023 Advanced Micro Devices, Inc. + * + * Author: Mario Limonciello <mario.limonciello@amd.com> + * + * Some of this code is adapted from drivers/i2c/busses/i2c-designware-amdpsp.c + * developed by Jan Dabros <jsd@semihalf.com> and Copyright (C) 2022 Google Inc. + * + */ + +#include <linux/bitfield.h> +#include <linux/errno.h> +#include <linux/iopoll.h> +#include <linux/mutex.h> + +#include "platform-access.h" + +#define PSP_CMD_TIMEOUT_US (500 * USEC_PER_MSEC) +#define DOORBELL_CMDRESP_STS GENMASK(7, 0) + +/* Recovery field should be equal 0 to start sending commands */ +static int check_recovery(u32 __iomem *cmd) +{ + return FIELD_GET(PSP_CMDRESP_RECOVERY, ioread32(cmd)); +} + +static int wait_cmd(u32 __iomem *cmd) +{ + u32 tmp, expected; + + /* Expect mbox_cmd to be cleared and ready bit to be set by PSP */ + expected = FIELD_PREP(PSP_CMDRESP_RESP, 1); + + /* + * Check for readiness of PSP mailbox in a tight loop in order to + * process further as soon as command was consumed. + */ + return readl_poll_timeout(cmd, tmp, (tmp & expected), 0, + PSP_CMD_TIMEOUT_US); +} + +int psp_check_platform_access_status(void) +{ + struct psp_device *psp = psp_get_master_device(); + + if (!psp || !psp->platform_access_data) + return -ENODEV; + + return 0; +} +EXPORT_SYMBOL(psp_check_platform_access_status); + +int psp_send_platform_access_msg(enum psp_platform_access_msg msg, + struct psp_request *req) +{ + struct psp_device *psp = psp_get_master_device(); + u32 __iomem *cmd, *lo, *hi; + struct psp_platform_access_device *pa_dev; + phys_addr_t req_addr; + u32 cmd_reg; + int ret; + + if (!psp || !psp->platform_access_data) + return -ENODEV; + + pa_dev = psp->platform_access_data; + + if (!pa_dev->vdata->cmdresp_reg || !pa_dev->vdata->cmdbuff_addr_lo_reg || + !pa_dev->vdata->cmdbuff_addr_hi_reg) + return -ENODEV; + + cmd = psp->io_regs + pa_dev->vdata->cmdresp_reg; + lo = psp->io_regs + pa_dev->vdata->cmdbuff_addr_lo_reg; + hi = psp->io_regs + pa_dev->vdata->cmdbuff_addr_hi_reg; + + mutex_lock(&pa_dev->mailbox_mutex); + + if (check_recovery(cmd)) { + dev_dbg(psp->dev, "platform mailbox is in recovery\n"); + ret = -EBUSY; + goto unlock; + } + + if (wait_cmd(cmd)) { + dev_dbg(psp->dev, "platform mailbox is not done processing command\n"); + ret = -EBUSY; + goto unlock; + } + + /* + * Fill mailbox with address of command-response buffer, which will be + * used for sending i2c requests as well as reading status returned by + * PSP. Use physical address of buffer, since PSP will map this region. + */ + req_addr = __psp_pa(req); + iowrite32(lower_32_bits(req_addr), lo); + iowrite32(upper_32_bits(req_addr), hi); + + print_hex_dump_debug("->psp ", DUMP_PREFIX_OFFSET, 16, 2, req, + req->header.payload_size, false); + + /* Write command register to trigger processing */ + cmd_reg = FIELD_PREP(PSP_CMDRESP_CMD, msg); + iowrite32(cmd_reg, cmd); + + if (wait_cmd(cmd)) { + ret = -ETIMEDOUT; + goto unlock; + } + + /* Ensure it was triggered by this driver */ + if (ioread32(lo) != lower_32_bits(req_addr) || + ioread32(hi) != upper_32_bits(req_addr)) { + ret = -EBUSY; + goto unlock; + } + + /* Store the status in request header for caller to investigate */ + cmd_reg = ioread32(cmd); + req->header.status = FIELD_GET(PSP_CMDRESP_STS, cmd_reg); + if (req->header.status) { + ret = -EIO; + goto unlock; + } + + print_hex_dump_debug("<-psp ", DUMP_PREFIX_OFFSET, 16, 2, req, + req->header.payload_size, false); + + ret = 0; + +unlock: + mutex_unlock(&pa_dev->mailbox_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(psp_send_platform_access_msg); + +int psp_ring_platform_doorbell(int msg, u32 *result) +{ + struct psp_device *psp = psp_get_master_device(); + struct psp_platform_access_device *pa_dev; + u32 __iomem *button, *cmd; + int ret, val; + + if (!psp || !psp->platform_access_data) + return -ENODEV; + + pa_dev = psp->platform_access_data; + button = psp->io_regs + pa_dev->vdata->doorbell_button_reg; + cmd = psp->io_regs + pa_dev->vdata->doorbell_cmd_reg; + + mutex_lock(&pa_dev->doorbell_mutex); + + if (wait_cmd(cmd)) { + dev_err(psp->dev, "doorbell command not done processing\n"); + ret = -EBUSY; + goto unlock; + } + + iowrite32(FIELD_PREP(DOORBELL_CMDRESP_STS, msg), cmd); + iowrite32(PSP_DRBL_RING, button); + + if (wait_cmd(cmd)) { + ret = -ETIMEDOUT; + goto unlock; + } + + val = FIELD_GET(DOORBELL_CMDRESP_STS, ioread32(cmd)); + if (val) { + if (result) + *result = val; + ret = -EIO; + goto unlock; + } + + ret = 0; +unlock: + mutex_unlock(&pa_dev->doorbell_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(psp_ring_platform_doorbell); + +void platform_access_dev_destroy(struct psp_device *psp) +{ + struct psp_platform_access_device *pa_dev = psp->platform_access_data; + + if (!pa_dev) + return; + + mutex_destroy(&pa_dev->mailbox_mutex); + mutex_destroy(&pa_dev->doorbell_mutex); + psp->platform_access_data = NULL; +} + +int platform_access_dev_init(struct psp_device *psp) +{ + struct device *dev = psp->dev; + struct psp_platform_access_device *pa_dev; + + pa_dev = devm_kzalloc(dev, sizeof(*pa_dev), GFP_KERNEL); + if (!pa_dev) + return -ENOMEM; + + psp->platform_access_data = pa_dev; + pa_dev->psp = psp; + pa_dev->dev = dev; + + pa_dev->vdata = (struct platform_access_vdata *)psp->vdata->platform_access; + + mutex_init(&pa_dev->mailbox_mutex); + mutex_init(&pa_dev->doorbell_mutex); + + dev_dbg(dev, "platform access enabled\n"); + + return 0; +} |