From df2f34ef1d924125ffaf29dfdaf7cdbd3183c321 Mon Sep 17 00:00:00 2001 From: Patrick Delaunay Date: Mon, 6 Feb 2023 13:43:52 +0000 Subject: [PATCH] nvmem: stm32: detect bsec pta presence for STM32MP15x 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 Reviewed-by: Etienne Carriere Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20230206134356.839737-19-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/nvmem/stm32-romem.c | 38 +++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) --- a/drivers/nvmem/stm32-romem.c +++ b/drivers/nvmem/stm32-romem.c @@ -159,6 +159,31 @@ static int stm32_bsec_pta_write(void *co 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; @@ -195,11 +220,16 @@ static int stm32_romem_probe(struct plat } 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) - return rc; + if (rc) { + /* wait for OP-TEE client driver to be up and ready */ + if (rc == -EPROBE_DEFER) + return -EPROBE_DEFER; + /* BSEC PTA is required or SMC not supported */ + if (cfg->ta || !stm32_bsec_smc_check()) + return rc; + } } if (priv->ctx) { rc = devm_add_action_or_reset(dev, stm32_bsec_optee_ta_close, priv->ctx);