From e58e6f2adfb65fb960cdc41289a5186b4370fd1e Mon Sep 17 00:00:00 2001 From: Aseda Aboagye Date: Tue, 15 Jun 2021 23:11:41 -0700 Subject: [PATCH] soc/intel/common/block/gpio: Add `gpio_lock_pad()` This commit adds a method for locking a GPIO pad configuration and its TX state. When the configuration is locked, the following registers become Read-Only and software writes to these registers have no effect. Pad Configuration registers GPI_NMI_EN GPI_SMI_EN GPI_GPE_EN Note that this is only effective if the pad is owned by the host (set in the PAD_OWN register). Intel platforms that wish to leverage this function need to define the PADCFGLOCK offset for their platform. BUG=b:191189275 BRANCH=None TEST=With some other code, call gpio_lock_pad() against a pad and verify that the pad configuration is locked and the state of the pad cannot be changed from the OS. Signed-off-by: Aseda Aboagye Change-Id: Id3c0da2f6942099c0289ca1e33a33c176f49d380 Reviewed-on: https://review.coreboot.org/c/coreboot/+/55557 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh Reviewed-by: Karthik Ramasubramanian --- src/soc/intel/common/block/gpio/gpio.c | 79 +++++++++++++++++++ .../common/block/include/intelblocks/gpio.h | 33 ++++++++ 2 files changed, 112 insertions(+) diff --git a/src/soc/intel/common/block/gpio/gpio.c b/src/soc/intel/common/block/gpio/gpio.c index 8f1c3a5601..d4a312bf9a 100644 --- a/src/soc/intel/common/block/gpio/gpio.c +++ b/src/soc/intel/common/block/gpio/gpio.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -446,6 +447,84 @@ int gpio_get(gpio_t gpio_num) return !!(reg & PAD_CFG0_RX_STATE); } +int gpio_lock_pad(const gpio_t pad, enum gpio_lock_action action) +{ + const struct pad_community *comm = gpio_get_community(pad); + size_t rel_pad; + uint16_t offset; + uint32_t data; + uint8_t response; + int status; + + /* + * FSP-S will unlock all the GPIO pads and hide the P2SB device. With + * the device hidden, we will not be able to send the sideband interface + * message to lock the GPIO configuration. Therefore, we need to unhide + * the P2SB device which can only be done in SMM requiring that this + * function is called from SMM. + */ + if (!ENV_SMM) { + printk(BIOS_ERR, "%s: Error: must be called from SMM!\n", __func__); + return -1; + } + + if (!(action & GPIO_LOCK_FULL)) { + printk(BIOS_ERR, "%s: Error: no action specified!\n", __func__); + return -1; + } + + rel_pad = relative_pad_in_comm(comm, pad); + offset = comm->pad_cfg_lock_offset; + if (!offset) { + printk(BIOS_ERR, "%s: Error: offset is not defined!\n", __func__); + return -1; + } + offset += gpio_group_index_scaled(comm, rel_pad, 2 * sizeof(uint32_t)); + + /* We must use the sideband interface in order to lock the pad. */ + struct pcr_sbi_msg msg = { + .pid = comm->port, + .offset = offset, + .opcode = GPIO_LOCK_UNLOCK, + .is_posted = false, + .fast_byte_enable = 0xF, + .bar = 0, + .fid = 0, + }; + + p2sb_unhide(); + + data = gpio_bitmask_within_group(comm, rel_pad); + + if (action & GPIO_LOCK_CONFIG) { + printk(BIOS_INFO, "%s: Locking pad %d configuration\n", + __func__, pad); + status = pcr_execute_sideband_msg(&msg, &data, &response); + if (status || response) { + printk(BIOS_ERR, "%s: error status=%x response=%x\n", __func__, status, + response); + p2sb_hide(); + return status == -1 ? -1 : response; + } + } + + if (action & GPIO_LOCK_TX) { + printk(BIOS_INFO, "%s: Locking pad %d TX state\n", __func__, + pad); + msg.offset = msg.offset + 4; + status = pcr_execute_sideband_msg(&msg, &data, &response); + if (status || response) { + printk(BIOS_ERR, "%s: error status=%x response=%x\n", __func__, status, + response); + p2sb_hide(); + return status == -1 ? -1 : response; + } + } + + p2sb_hide(); + return 0; +} + void gpio_set(gpio_t gpio_num, int value) { const struct pad_community *comm = gpio_get_community(gpio_num); diff --git a/src/soc/intel/common/block/include/intelblocks/gpio.h b/src/soc/intel/common/block/include/intelblocks/gpio.h index 86a36d5e6b..8496db32c5 100644 --- a/src/soc/intel/common/block/include/intelblocks/gpio.h +++ b/src/soc/intel/common/block/include/intelblocks/gpio.h @@ -121,6 +121,7 @@ struct pad_community { uint16_t gpi_nmi_sts_reg_0; /* offset to GPI NMI STS Reg 0 */ uint16_t gpi_nmi_en_reg_0; /* offset to GPI NMI EN Reg 0 */ uint16_t pad_cfg_base; /* offset to first PAD_GFG_DW0 Reg */ + uint16_t pad_cfg_lock_offset; /* offset to first PADCFGLOCK Reg */ uint8_t gpi_status_offset; /* specifies offset in struct gpi_status */ uint8_t port; /* PCR Port ID */ @@ -197,6 +198,38 @@ void gpio_configure_pads_with_override(const struct pad_config *base_cfg, */ void *gpio_dwx_address(const gpio_t pad); +enum gpio_lock_action { + GPIO_LOCK_CONFIG = 0x1, + GPIO_LOCK_TX = 0x2, + GPIO_LOCK_FULL = GPIO_LOCK_CONFIG | GPIO_LOCK_TX, +}; + +/* + * Lock a GPIO's configuration. + * + * The caller may specify if they wish to only lock the pad configuration, only + * the TX state, or both. When the configuration is locked, the following + * registers become Read-Only and software writes to these registers have no + * effect. + * + * Pad Configuration registers, + * GPI_NMI_EN, + * GPI_SMI_EN, + * GPI_GPE_EN + * + * Note that this is only effective if the pad is owned by the host and this + * function may only be called in SMM. + * + * @param pad: GPIO pad number + * @param action: Which register to lock. + * @return 0 if successful, + * 1 - unsuccessful + * 2 - powered down + * 3 - multi-cast mixed + * -1 - sideband message failed or other error + */ +int gpio_lock_pad(const gpio_t pad, enum gpio_lock_action action); + /* * Returns the pmc_gpe to gpio_gpe mapping table *