From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Add a new Kconfig option for selecting the SHM Bridge mode of operation
for the TrustZone memory allocator.
If enabled at build-time, it will still be checked for availability at
run-time. If the architecture doesn't support SHM Bridge, the allocator
will work just like in the default mode.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Tested-by: Andrew Halaney <ahalaney@xxxxxxxxxx> # sc8280xp-lenovo-thinkpad-x13s
---
drivers/firmware/qcom/Kconfig | 10 +++++
drivers/firmware/qcom/qcom_tzmem.c | 65 +++++++++++++++++++++++++++++-
2 files changed, 74 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig
index 237da40de832..e01407e31ae4 100644
--- a/drivers/firmware/qcom/Kconfig
+++ b/drivers/firmware/qcom/Kconfig
@@ -27,6 +27,16 @@ config QCOM_TZMEM_MODE_DEFAULT
Use the default allocator mode. The memory is page-aligned, non-cachable
and contiguous.
+config QCOM_TZMEM_MODE_SHMBRIDGE
+ bool "SHM Bridge"
+ help
+ Use Qualcomm Shared Memory Bridge. The memory has the same alignment as
+ in the 'Default' allocator but is also explicitly marked as an SHM Bridge
+ buffer.
+
+ With this selected, all buffers passed to the TrustZone must be allocated
+ using the TZMem allocator or else the TrustZone will refuse to use them.
+
endchoice
config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
diff --git a/drivers/firmware/qcom/qcom_tzmem.c b/drivers/firmware/qcom/qcom_tzmem.c
index 68ca59c5598e..8010af80fd59 100644
--- a/drivers/firmware/qcom/qcom_tzmem.c
+++ b/drivers/firmware/qcom/qcom_tzmem.c
@@ -55,7 +55,70 @@ static void qcom_tzmem_cleanup_pool(struct qcom_tzmem_pool *pool)
}
-#endif /* CONFIG_QCOM_TZMEM_MODE_DEFAULT */
+#elif IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE)
+
+#include <linux/firmware/qcom/qcom_scm.h>
+
+#define QCOM_SHM_BRIDGE_NUM_VM_SHIFT 9
+
+static bool qcom_tzmem_using_shm_bridge;
+
+static int qcom_tzmem_init(void)
+{
+ int ret;
+
+ ret = qcom_scm_shm_bridge_enable();
+ if (ret == -EOPNOTSUPP) {
+ dev_info(qcom_tzmem_dev, "SHM Bridge not supported\n");
+ return 0;
+ }
+
+ if (!ret)
+ qcom_tzmem_using_shm_bridge = true;
+
+ return ret;
+}
+
+static int qcom_tzmem_init_pool(struct qcom_tzmem_pool *pool)
+{
+ u64 pfn_and_ns_perm, ipfn_and_s_perm, size_and_flags, ns_perms;
+ int ret;
+
+ if (!qcom_tzmem_using_shm_bridge)
+ return 0;
+
+ ns_perms = (QCOM_SCM_PERM_WRITE | QCOM_SCM_PERM_READ);
+ pfn_and_ns_perm = (u64)pool->pbase | ns_perms;
+ ipfn_and_s_perm = (u64)pool->pbase | ns_perms;
+ size_and_flags = pool->size | (1 << QCOM_SHM_BRIDGE_NUM_VM_SHIFT);
+
+ u64 *handle __free(kfree) = kzalloc(sizeof(*handle), GFP_KERNEL);
+ if (!handle)
+ return -ENOMEM;
+
+ ret = qcom_scm_shm_bridge_create(qcom_tzmem_dev, pfn_and_ns_perm,
+ ipfn_and_s_perm, size_and_flags,
+ QCOM_SCM_VMID_HLOS, handle);
+ if (ret)
+ return ret;
+
+ pool->priv = no_free_ptr(handle);
+
+ return 0;
+}
+
+static void qcom_tzmem_cleanup_pool(struct qcom_tzmem_pool *pool)
+{
+ u64 *handle = pool->priv;
+
+ if (!qcom_tzmem_using_shm_bridge)
+ return;
+
+ qcom_scm_shm_bridge_delete(qcom_tzmem_dev, *handle);
+ kfree(handle);
+}
+
+#endif /* CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE */
/**
* qcom_tzmem_pool_new() - Create a new TZ memory pool.
--
2.40.1
