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From:   Valentin David <valentin.david@gmail.com>
To:     Peter Huewe <peterhuewe@gmx.de>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Jason Gunthorpe <jgg@ziepe.ca>
Cc:     linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        Valentin David <valentin.david@gmail.com>
Subject: [PATCH v2] tpm: Do not remap from ACPI resouces again for Pluton TPM
Date:   Thu,  6 Jul 2023 21:13:40 +0200
Message-ID: <20230706191409.737080-1-valentin.david@gmail.com>
In-Reply-To: <20230701153329.6476-1-valentin.david@gmail.com>
References: <20230701153329.6476-1-valentin.david@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@gmail.com>
---
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