Re: [PATCH v6 3/3] nvmem: stm32: detect bsec pta presence for STM32MP15x
From: Srinivas Kandagatla <hidden>
Date: 2023-01-20 17:42:24
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On 18/01/2023 17:29, Patrick Delaunay wrote:
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> Reviewed-by: Etienne Carriere <redacted> ---
Applied thanks, --srini
quoted hunk ↗ jump to hunk
Changes in v6: - added reviewed by Etienne Carriere Changes in v5: - update the BSEC SMC detection logic in stm32_romem_probe() after Etienne Carierre review to support NVMEM probe after OP-TEE probe 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 | 38 +++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-)diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c index 978a63edf297..ba779e26937a 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;@@ -195,11 +220,16 @@ 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) - 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);
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