[PATCH 2/3] soc: qcom: smem: better track SMEM uninitialized state

Christian Marangi
2025-10-29T13:33:36Z

There is currently a problem where, in the specific case of SMEM not
initialized by SBL, any SMEM API wrongly returns PROBE_DEFER
communicating wrong info to any user of this API.

A better way to handle this would be to track the SMEM state and return
a different kind of error than PROBE_DEFER.

Rework the __smem handle to always init it to the error pointer
-EPROBE_DEFER following what is already done by the SMEM API.
If we detect that the SBL didn't initialized SMEM, set the __smem handle
to the error pointer -ENODEV.
Also rework the SMEM API to handle the __smem handle to be an error
pointer and return it appropriately.

This way user of the API can react and return a proper error or use
fallback way for the failing API.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
drivers/soc/qcom/smem.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index 592819701809..d6136369262a 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -353,8 +353,12 @@ static void *cached_entry_to_item(struct smem_private_entry *e)
return p - le32_to_cpu(e->size);
}

-/* Pointer to the one and only smem handle */
-static struct qcom_smem *__smem;
+/*
+ * Pointer to the one and only smem handle.
+ * Init to -EPROBE_DEFER to signal SMEM still has to be probed.
+ * Can be set to -ENODEV if SMEM is not initialized by SBL.
+ */
+static struct qcom_smem *__smem = ERR_PTR_CONST(-EPROBE_DEFER);

/* Timeout (ms) for the trylock of remote spinlocks */
#define HWSPINLOCK_TIMEOUT 1000
@@ -508,8 +512,8 @@ int qcom_smem_alloc(unsigned host, unsigned item, size_t size)
unsigned long flags;
int ret;

- if (!__smem)
- return -EPROBE_DEFER;
+ if (IS_ERR(__smem))
+ return PTR_ERR(__smem);

if (item < SMEM_ITEM_LAST_FIXED) {
dev_err(__smem->dev,
@@ -685,10 +689,10 @@ static void *qcom_smem_get_private(struct qcom_smem *smem,
void *qcom_smem_get(unsigned host, unsigned item, size_t *size)
{
struct smem_partition *part;
- void *ptr = ERR_PTR(-EPROBE_DEFER);
+ void *ptr;

- if (!__smem)
- return ptr;
+ if (IS_ERR(__smem))
+ return __smem;

if (WARN_ON(item >= __smem->item_count))
return ERR_PTR(-EINVAL);
@@ -723,8 +727,8 @@ int qcom_smem_get_free_space(unsigned host)
struct smem_header *header;
unsigned ret;

- if (!__smem)
- return -EPROBE_DEFER;
+ if (IS_ERR(__smem))
+ return PTR_ERR(__smem);

if (host < SMEM_HOST_COUNT && __smem->partitions[host].virt_base) {
part = &__smem->partitions[host];
@@ -1182,6 +1186,7 @@ static int qcom_smem_probe(struct platform_device *pdev)
if (le32_to_cpu(header->initialized) != 1 ||
le32_to_cpu(header->reserved)) {
dev_err(&pdev->dev, "SMEM is not initialized by SBL\n");
+ __smem = ERR_PTR(-ENODEV);
return -EINVAL;
}

--
2.51.0