[PATCH v2 1/2] optee: fix tee out of memory failure seen during kexec reboot

[Allen Pais]

From: Allen Pais <apais at linux.microsoft.com>

The following out of memory errors are seen on kexec reboot
from the optee core.

[    0.368428] tee_bnxt_fw optee-clnt0: tee_shm_alloc failed
[    0.368461] tee_bnxt_fw: probe of optee-clnt0 failed with error -22

tee_shm_release() is not invoked on dma shm buffer.

Implement .shutdown() method to handle the release of the buffers
correctly.

More info:
https://github.com/OP-TEE/optee_os/issues/3637

Signed-off-by: Allen Pais <apais at linux.microsoft.com>
---
 drivers/tee/optee/core.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index cf4718c6d35d..80e2774b5e2a 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -582,6 +582,13 @@ static optee_invoke_fn *get_invoke_func(struct device *dev)
 	return ERR_PTR(-EINVAL);
 }
 
+/* optee_remove - Device Removal Routine
+ * @pdev: platform device information struct
+ *
+ * optee_remove is called by platform subsystem to alter the driver
+ * that it should release the device
+ */
+
 static int optee_remove(struct platform_device *pdev)
 {
 	struct optee *optee = platform_get_drvdata(pdev);
@@ -612,6 +619,18 @@ static int optee_remove(struct platform_device *pdev)
 	return 0;
 }
 
+/* optee_shutdown - Device Removal Routine
+ * @pdev: platform device information struct
+ *
+ * platform_shutdown is called by the platform subsystem to alter
+ * the driver that a shutdown/reboot(or kexec) is happening and
+ * device must be disabled.
+ */
+static void optee_shutdown(struct platform_device *pdev)
+{
+	optee_disable_shm_cache(platform_get_drvdata(pdev));
+}
+
 static int optee_probe(struct platform_device *pdev)
 {
 	optee_invoke_fn *invoke_fn;
@@ -738,6 +757,7 @@ MODULE_DEVICE_TABLE(of, optee_dt_match);
 static struct platform_driver optee_driver = {
 	.probe  = optee_probe,
 	.remove = optee_remove,
+	.shutdown = optee_shutdown,
 	.driver = {
 		.name = "optee",
 		.of_match_table = optee_dt_match,
-- 
2.25.1