[PATCH v4 3/3] nvmem: stm32: detect bsec pta presence for STM32MP15x
From: Patrick Delaunay <hidden>
Date: 2023-01-03 14:08:43
Also in:
lkml
Subsystem:
nvmem framework, the rest · Maintainers:
Srinivas Kandagatla, Linus Torvalds
On STM32MP15x SoC, the SMC backend is optional when OP-TEE is used;
the PTA BSEC should be used as it is done on STM32MP13x platform,
but the BSEC SMC can be also used: it is a legacy mode in OP-TEE,
not recommended but used in previous OP-TEE firmware.
The presence of OP-TEE is dynamically detected in STM32MP15x device tree
and the supported NVMEM backend is dynamically detected:
- PTA with stm32_bsec_pta_find
- SMC with stm32_bsec_check
With OP-TEE but without PTA and SMC detection, the probe is deferred for
STM32MP15x devices.
On STM32MP13x platform, only the PTA is supported with cfg->ta = true
and this detection is skipped.
Signed-off-by: Patrick Delaunay <redacted>
---
(no changes since v3)
Changes in v3:
- use of_find_compatible_node in optee_presence_check function
instead of of_find_node_by_path("/firmware/optee")
Changes in v2:
- Added patch in the serie for BSEC PTA support on STM32MP15x
with dynamic detection of OP-TEE presence and SMC support (legacy mode)
drivers/nvmem/stm32-romem.c | 33 +++++++++++++++++++++++++++++++--
1 file changed, 31 insertions(+), 2 deletions(-)
diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
index 2edc61925e52..1b90c78301fa 100644
--- a/drivers/nvmem/stm32-romem.c
+++ b/drivers/nvmem/stm32-romem.c@@ -159,6 +159,31 @@ static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf, return stm32_bsec_optee_ta_write(priv->ctx, priv->lower, offset, buf, bytes); } +static bool stm32_bsec_smc_check(void) +{ + u32 val; + int ret; + + /* check that the OP-TEE support the BSEC SMC (legacy mode) */ + ret = stm32_bsec_smc(STM32_SMC_READ_SHADOW, 0, 0, &val); + + return !ret; +} + +static bool optee_presence_check(void) +{ + struct device_node *np; + bool tee_detected = false; + + /* check that the OP-TEE node is present and available. */ + np = of_find_compatible_node(NULL, NULL, "linaro,optee-tz"); + if (np && of_device_is_available(np)) + tee_detected = true; + of_node_put(np); + + return tee_detected; +} + static int stm32_romem_probe(struct platform_device *pdev) { const struct stm32_romem_cfg *cfg;
@@ -195,10 +220,14 @@ static int stm32_romem_probe(struct platform_device *pdev) } else { priv->cfg.size = cfg->size; priv->lower = cfg->lower; - if (cfg->ta) { + if (cfg->ta || optee_presence_check()) { rc = stm32_bsec_optee_ta_open(&priv->ctx); /* wait for OP-TEE client driver to be up and ready */ - if (rc) + if (rc == -EPROBE_DEFER) { + /* BSEC PTA is required or SMC not ready */ + if (cfg->ta || !stm32_bsec_smc_check()) + return -EPROBE_DEFER; + } else if (rc) return rc; rc = devm_add_action_or_reset(dev, stm32_bsec_optee_ta_close, priv->ctx); if (rc) {
--
2.25.1
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