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nvmem: stm32: detect bsec pta presence for stm32mp15

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On STM32MP15, the SMC backend is optional when OP-TEE is used;
the PTA BSEC should be used as it is done on STM32MP13 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

Without PTA and SMC detection, the probe is defered for STM32MP15 device.

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>
Change-Id: I59210046e368cfc22bd3cca2afe1653674f8ece8
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/linux-stm32/+/266103
Reviewed-by: CITOOLS <MDG-smet-aci-reviews@list.st.com>
This commit is contained in:
Patrick Delaunay
2021-10-19 10:43:38 +02:00
committed by Eric Fourmont
parent d6e1a568d8
commit 5aceeee7e8
1 changed files with 33 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
drivers/nvmem/stm32-romem.c
View File

@ -73,6 +73,17 @@ static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result)
#endif
}
static bool stm32_bsec_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 int stm32_bsec_read(void *context, unsigned int offset, void *buf,
size_t bytes)
{
@ -147,6 +158,20 @@ static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
return 0;
}
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;
@ -182,12 +207,16 @@ 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()) {
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_check())
return -EPROBE_DEFER;
}
}
if (priv->ta) {
priv->cfg.reg_read = stm32_bsec_pta_read;
priv->cfg.reg_write = stm32_bsec_pta_write;
} else {