[PATCH 2/2] soc: qcom: add MDSS DSM memory driver

[Neil Armstrong]

This adds a driver for the Qualcomm Modem Processing SubSystem DSM memory
used to assign such regions of memory with remote MPSS processors.

Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
 drivers/of/platform.c           |  1 +
 drivers/soc/qcom/Kconfig        | 10 +++++
 drivers/soc/qcom/Makefile       |  1 +
 drivers/soc/qcom/mpss_dsm_mem.c | 95 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 107 insertions(+)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 81c8c227ab6b..d5a9962641f4 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -504,6 +504,7 @@ EXPORT_SYMBOL_GPL(of_platform_default_populate);
 
 static const struct of_device_id reserved_mem_matches[] = {
 	{ .compatible = "phram" },
+	{ .compatible = "qcom,mpss-dsm-mem" },
 	{ .compatible = "qcom,rmtfs-mem" },
 	{ .compatible = "qcom,cmd-db" },
 	{ .compatible = "qcom,smem" },
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 024e420f1bb7..7624a8af56bf 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -95,6 +95,16 @@ config QCOM_QMI_HELPERS
 	tristate
 	depends on NET
 
+config QCOM_MPSS_DSM_MEM
+	tristate "Qualcomm Modem Processing SubSystem DSM memory driver"
+	depends on ARCH_QCOM
+	select QCOM_SCM
+	help
+	  The Qualcomm Modem Processing SubSystem DSM memory driver is used to
+	  assign regions of DSM memory with remote MPSS processors.
+
+	  Say y here if you intend to boot the modem remoteproc.
+
 config QCOM_RMTFS_MEM
 	tristate "Qualcomm Remote Filesystem memory driver"
 	depends on ARCH_QCOM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index d66604aff2b0..0d0e850f1a18 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -16,6 +16,7 @@ qcom_rpmh-y			+= rpmh-rsc.o
 qcom_rpmh-y			+= rpmh.o
 obj-$(CONFIG_QCOM_SMD_RPM)	+= smd-rpm.o
 obj-$(CONFIG_QCOM_SMEM) +=	smem.o
+obj-$(CONFIG_QCOM_MPSS_DSM_MEM) += mpss_dsm_mem.o
 obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
 obj-$(CONFIG_QCOM_SMP2P)	+= smp2p.o
 obj-$(CONFIG_QCOM_SMSM)	+= smsm.o
diff --git a/drivers/soc/qcom/mpss_dsm_mem.c b/drivers/soc/qcom/mpss_dsm_mem.c
new file mode 100644
index 000000000000..5584bd101aee
--- /dev/null
+++ b/drivers/soc/qcom/mpss_dsm_mem.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022 Linaro Ltd.
+ */
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/slab.h>
+#include <linux/qcom_scm.h>
+
+struct qcom_mpss_dsm_mem {
+	phys_addr_t addr;
+	phys_addr_t size;
+
+	unsigned int perms;
+};
+
+static int qcom_mpss_dsm_mem_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct qcom_scm_vmperm perm;
+	struct reserved_mem *rmem;
+	struct qcom_mpss_dsm_mem *mpss_dsm_mem;
+	int ret;
+
+	if (!qcom_scm_is_available())
+		return -EPROBE_DEFER;
+
+	rmem = of_reserved_mem_lookup(node);
+	if (!rmem) {
+		dev_err(&pdev->dev, "failed to acquire memory region\n");
+		return -EINVAL;
+	}
+
+	mpss_dsm_mem = kzalloc(sizeof(*mpss_dsm_mem), GFP_KERNEL);
+	if (!mpss_dsm_mem)
+		return -ENOMEM;
+
+	mpss_dsm_mem->addr = rmem->base;
+	mpss_dsm_mem->size = rmem->size;
+
+	perm.vmid = QCOM_SCM_VMID_MSS_MSA;
+	perm.perm = QCOM_SCM_PERM_RW;
+
+	mpss_dsm_mem->perms = BIT(QCOM_SCM_VMID_HLOS);
+	ret = qcom_scm_assign_mem(mpss_dsm_mem->addr, mpss_dsm_mem->size,
+				  &mpss_dsm_mem->perms, &perm, 1);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "assign memory failed\n");
+		return ret;
+	}
+
+	dev_set_drvdata(&pdev->dev, mpss_dsm_mem);
+
+	return 0;
+}
+
+static int qcom_mpss_dsm_mem_remove(struct platform_device *pdev)
+{
+	struct qcom_mpss_dsm_mem *mpss_dsm_mem = dev_get_drvdata(&pdev->dev);
+	struct qcom_scm_vmperm perm;
+
+	perm.vmid = QCOM_SCM_VMID_HLOS;
+	perm.perm = QCOM_SCM_PERM_RW;
+
+	qcom_scm_assign_mem(mpss_dsm_mem->addr, mpss_dsm_mem->size,
+			    &mpss_dsm_mem->perms, &perm, 1);
+
+	return 0;
+}
+
+static const struct of_device_id qcom_mpss_dsm_mem_of_match[] = {
+	{ .compatible = "qcom,mpss-dsm-mem" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_mpss_dsm_mem_of_match);
+
+static struct platform_driver qcom_mpss_dsm_mem_driver = {
+	.probe = qcom_mpss_dsm_mem_probe,
+	.remove = qcom_mpss_dsm_mem_remove,
+	.driver  = {
+		.name  = "qcom_mpss_dsm_mem",
+		.of_match_table = qcom_mpss_dsm_mem_of_match,
+	},
+};
+
+module_platform_driver(qcom_mpss_dsm_mem_driver);
+
+MODULE_AUTHOR("Linaro Ltd");
+MODULE_DESCRIPTION("Qualcomm DSM memory driver");
+MODULE_LICENSE("GPL");

-- 
b4 0.10.1