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nvmem: stm32: detect bsec pta presence for STM32MP15x

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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 <patrick.delaunay@foss.st.com>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230206134356.839737-19-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Patrick Delaunay 2023-02-06 13:43:52 +00:00 committed by Greg Kroah-Hartman
parent 6a0bc3522e
commit df2f34ef1d
1 changed files with 34 additions and 4 deletions
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38
drivers/nvmem/stm32-romem.c
View file

@ -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);