[PATCH v2] tpm: Do not remap from ACPI resouces again for Pluton TPM

From: Valentin David
Date: Thu Jul 06 2023 - 15:14:30 EST


For Pluton TPM devices, it was assumed that there was no ACPI memory
regions. This is not true for ASUS ROG Ally. ACPI advertises
0xfd500000-0xfd5fffff.

Since remapping is already done in `crb_map_pluton`, remapping again
in `crb_map_io` causes EBUSY error:
```
[ 3.510453] tpm_crb MSFT0101:00: can't request region for resource [mem 0xfd500000-0xfd5fffff]
[ 3.510463] tpm_crb: probe of MSFT0101:00 failed with error -16
```

Signed-off-by: Valentin David <valentin.david@xxxxxxxxx>
---
v2: add missing sign-off in commit message
---
drivers/char/tpm/tpm_crb.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index d43a0d7b97a8..1a5d09b18513 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -563,15 +563,18 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
u32 rsp_size;
int ret;

- INIT_LIST_HEAD(&acpi_resource_list);
- ret = acpi_dev_get_resources(device, &acpi_resource_list,
- crb_check_resource, iores_array);
- if (ret < 0)
- return ret;
- acpi_dev_free_resource_list(&acpi_resource_list);
-
- /* Pluton doesn't appear to define ACPI memory regions */
+ /*
+ * Pluton sometimes does not define ACPI memory regions.
+ * Mapping is then done in crb_map_pluton
+ */
if (priv->sm != ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON) {
+ INIT_LIST_HEAD(&acpi_resource_list);
+ ret = acpi_dev_get_resources(device, &acpi_resource_list,
+ crb_check_resource, iores_array);
+ if (ret < 0)
+ return ret;
+ acpi_dev_free_resource_list(&acpi_resource_list);
+
if (resource_type(iores_array) != IORESOURCE_MEM) {
dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
return -EINVAL;
--
2.41.0