[PATCH 2/2] soc: qcom: rmtfs: Support dynamic placement of region

[Bjorn Andersson]

In some configurations, the exact placement of the rmtfs shared memory
region isn't so strict. In the current implementation the author of the
DeviceTree source is forced to make up a memory region.

Extend the rmtfs memory driver to relieve the author of this
responsibility by introducing support for using dynamic allocation in
the driver.

Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
---
 arch/arm64/boot/dts/qcom/sdm845-mtp.dts | 10 ++++
 drivers/soc/qcom/rmtfs_mem.c            | 66 +++++++++++++++++++------
 2 files changed, 61 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sdm845-mtp.dts b/arch/arm64/boot/dts/qcom/sdm845-mtp.dts
index d1440b790fa6..e6191b8ba4c6 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-mtp.dts
+++ b/arch/arm64/boot/dts/qcom/sdm845-mtp.dts
@@ -12,6 +12,8 @@
 #include "pm8998.dtsi"
 #include "pmi8998.dtsi"
 
+/delete-node/ &rmtfs_mem;
+
 / {
 	model = "Qualcomm Technologies, Inc. SDM845 MTP";
 	compatible = "qcom,sdm845-mtp", "qcom,sdm845";
@@ -48,6 +50,14 @@ vreg_s4a_1p8: pm8998-smps4 {
 		vin-supply = <&vph_pwr>;
 	};
 
+	rmtfs {
+		compatible = "qcom,rmtfs-mem";
+
+		qcom,alloc-size = <(2*1024*1024)>;
+		qcom,client-id = <1>;
+		qcom,vmid = <15>;
+	};
+
 	thermal-zones {
 		xo_thermal: xo-thermal {
 			polling-delay-passive = <0>;
diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c
index f83811f51175..5f56ded9f905 100644
--- a/drivers/soc/qcom/rmtfs_mem.c
+++ b/drivers/soc/qcom/rmtfs_mem.c
@@ -3,6 +3,8 @@
  * Copyright (c) 2017 Linaro Ltd.
  */
 
+#include "linux/gfp_types.h"
+#include "linux/sizes.h"
 #include <linux/kernel.h>
 #include <linux/cdev.h>
 #include <linux/err.h>
@@ -168,23 +170,63 @@ static void qcom_rmtfs_mem_release_device(struct device *dev)
 	kfree(rmtfs_mem);
 }
 
+static int qcom_rmtfs_acquire_mem(struct device *dev, struct qcom_rmtfs_mem *rmtfs_mem)
+{
+	struct device_node *node = dev->of_node;
+	struct reserved_mem *rmem;
+	dma_addr_t dma_addr;
+	void *mem;
+	u32 size;
+	int ret;
+
+	rmem = of_reserved_mem_lookup(node);
+	if (rmem) {
+		rmtfs_mem->addr = rmem->base;
+		rmtfs_mem->size = rmem->size;
+
+		rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
+						rmtfs_mem->size, MEMREMAP_WC);
+		if (IS_ERR(rmtfs_mem->base)) {
+			dev_err(dev, "failed to remap rmtfs_mem region\n");
+			return PTR_ERR(rmtfs_mem->base);
+		}
+
+		return 0;
+	}
+
+	ret = of_property_read_u32(node, "qcom,alloc-size", &size);
+	if (ret < 0) {
+		dev_err(dev, "rmtfs of unknown size\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Ensure that the protected region isn't adjacent to other protected
+	 * regions by allocating an empty page on either side.
+	 */
+	mem = dma_alloc_coherent(dev, size + 2 * SZ_4K, &dma_addr, GFP_KERNEL);
+	if (mem) {
+		rmtfs_mem->base = mem + SZ_4K;
+		rmtfs_mem->addr = dma_addr + SZ_4K;
+		rmtfs_mem->size = size;
+
+		return 0;
+	}
+
+	dev_err(dev, "unable to allocate memory for rmtfs mem\n");
+	return -ENOMEM;
+}
+
 static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
 	struct qcom_scm_vmperm perms[NUM_MAX_VMIDS + 1];
-	struct reserved_mem *rmem;
 	struct qcom_rmtfs_mem *rmtfs_mem;
 	u32 client_id;
 	u32 vmid[NUM_MAX_VMIDS];
 	int num_vmids;
 	int ret, i;
 
-	rmem = of_reserved_mem_lookup(node);
-	if (!rmem) {
-		dev_err(&pdev->dev, "failed to acquire memory region\n");
-		return -EINVAL;
-	}
-
 	ret = of_property_read_u32(node, "qcom,client-id", &client_id);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n");
@@ -196,22 +238,16 @@ static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
 	if (!rmtfs_mem)
 		return -ENOMEM;
 
-	rmtfs_mem->addr = rmem->base;
 	rmtfs_mem->client_id = client_id;
-	rmtfs_mem->size = rmem->size;
 
 	device_initialize(&rmtfs_mem->dev);
 	rmtfs_mem->dev.parent = &pdev->dev;
 	rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
 	rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
 
-	rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
-					rmtfs_mem->size, MEMREMAP_WC);
-	if (IS_ERR(rmtfs_mem->base)) {
-		dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
-		ret = PTR_ERR(rmtfs_mem->base);
+	ret = qcom_rmtfs_acquire_mem(&pdev->dev, rmtfs_mem);
+	if (ret < 0)
 		goto put_device;
-	}
 
 	cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops);
 	rmtfs_mem->cdev.owner = THIS_MODULE;
-- 
2.25.1