[PATCH 2/2] misc: fastrpc: support complete DMA pool access to the DSP

[Dylan Van Assche <me@dylanvanassche.be>]

To support FastRPC Context Banks which aren't mapped via the SMMU,
make the whole reserved memory region available to the DSP to allow
access to coherent buffers.

This is performed by assigning the memory to the DSP via a hypervisor
call to set the correct permissions for the Virtual Machines on the DSP.
Only perform this operation when at least one VM is enabled
and 'qcom,assign-all-mem' property is present in DTS.

Signed-off-by: Dylan Van Assche <me@dylanvanassche.be>
---
 drivers/misc/fastrpc.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index f48466960f1b..ecfd0a91113c 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -2230,7 +2230,9 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 	struct fastrpc_channel_ctx *data;
 	int i, err, domain_id = -1, vmcount;
 	const char *domain;
-	bool secure_dsp;
+	bool secure_dsp, assign_all_mem;
+	struct device_node *rmem_node;
+	struct reserved_mem *rmem;
 	unsigned int vmids[FASTRPC_MAX_VMIDS];
 
 	err = of_property_read_string(rdev->of_node, "label", &domain);
@@ -2265,6 +2267,11 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 	if (!data)
 		return -ENOMEM;
 
+	assign_all_mem = of_property_read_bool(rdev->of_node, "qcom,assign-all-mem");
+
+	if (assign_all_mem && !vmcount)
+		return -EINVAL;
+
 	if (vmcount) {
 		data->vmcount = vmcount;
 		data->perms = BIT(QCOM_SCM_VMID_HLOS);
@@ -2274,6 +2281,16 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 		}
 	}
 
+	if (assign_all_mem) {
+		rmem_node = of_parse_phandle(rdev->of_node, "memory-region", 0);
+		if (rmem_node) {
+			rmem = of_reserved_mem_lookup(rmem_node);
+			if (rmem)
+				qcom_scm_assign_mem(rmem->base, rmem->size, &data->perms,
+						    data->vmperms, data->vmcount);
+		}
+	}
+
 	secure_dsp = !(of_property_read_bool(rdev->of_node, "qcom,non-secure-domain"));
 	data->secure = secure_dsp;
 
-- 
2.39.2