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

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Message-ID: <20230530193436.3833889-3-quic_bjorande@quicinc.com>
Date:   Tue, 30 May 2023 12:34:36 -0700
From:   Bjorn Andersson <quic_bjorande@...cinc.com>
To:     Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>
CC:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        <linux-arm-msm@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] soc: qcom: rmtfs: Support dynamic placement of region

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@...cinc.com>
---
 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