[PATCH v2 3/3] nvmem: stm32: detect bsec pta presence for STM32MP15x
From: Patrick Delaunay <hidden>
Date: 2022-11-10 15:46:47
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> --- 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 | 37 +++++++++++++++++++++++++++++++++---- 1 file changed, 33 insertions(+), 4 deletions(-)
diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
index 0a0e29d09b67..35997d581c9d 100644
--- a/drivers/nvmem/stm32-romem.c
+++ b/drivers/nvmem/stm32-romem.c@@ -526,6 +526,31 @@ static int stm32_bsec_write(void *context, unsigned int offset, void *buf, return 0; } +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_node_by_path("/firmware/optee"); + 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;
@@ -561,14 +586,18 @@ 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()) { priv->ta = stm32_bsec_pta_find(dev); /* wait for OP-TEE client driver to be up and ready */ - if (!priv->ta) - return -EPROBE_DEFER; + if (!priv->ta) { + /* BSEC PTA is required or SMC not ready */ + if (cfg->ta || !stm32_bsec_smc_check()) + return -EPROBE_DEFER; + } if (IS_ERR(priv->ta)) return PTR_ERR(priv->ta); - + } + if (priv->ta) { priv->cfg.reg_read = stm32_bsec_pta_read; priv->cfg.reg_write = stm32_bsec_pta_write; } else {
--
2.25.1
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