uio: Add snapshot of MSM sharedmem driver

This is a snapshot of the MSM sharedmem driver as of msm-3.14
commit:
commit <149717c0> ("uio: msm_sharedmem: Add custom mmap") +
sharedmem qmi logic is removed.

The following changes are included:
02d55287 uio: msm_sharedmem: Restrict debugfs write to root.
de961fc7 uio: msm_sharedmem: Return ENOMEM if the shared mem addr
	 is zero.
b974ce64 uio: msm_sharedmem: Add addtional information to debugfs
c46af547 uio: msm_sharedmem: Add support for dynamic shared memory
	 allocation

Change-Id: I49902f018bde1d59d41027b7e46268cc17231a3e
Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Signed-off-by: Ankit Jain <jankit@codeaurora.org>
Signed-off-by: Richard Patrick <richardp@codeaurora.org>

drivers/uio/Kconfig

@@ -165,4 +165,14 @@ config UIO_HV_GENERIC
 	  to network and storage devices from userspace.
 
 	  If you compile this as a module, it will be called uio_hv_generic.
+
+config UIO_MSM_SHAREDMEM
+	bool "MSM shared memory driver"
+	default n
+	help
+	  Provides the clients with their respective alloted shared memory
+	  addresses which are used as transport buffer.
+
+	  If you don't know what to do here, say N.
+
 endif

drivers/uio/Makefile

@@ -11,3 +11,4 @@ obj-$(CONFIG_UIO_PRUSS)         += uio_pruss.o
 obj-$(CONFIG_UIO_MF624)         += uio_mf624.o
 obj-$(CONFIG_UIO_FSL_ELBC_GPCM)	+= uio_fsl_elbc_gpcm.o
 obj-$(CONFIG_UIO_HV_GENERIC)	+= uio_hv_generic.o
+obj-$(CONFIG_UIO_MSM_SHAREDMEM) += msm_sharedmem/

drivers/uio/msm_sharedmem/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_UIO_MSM_SHAREDMEM) := msm_sharedmem.o

drivers/uio/msm_sharedmem/msm_sharedmem.c

@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2015-2019, The Linux Foundation. All rights reserved.
+ */
+
+#define DRIVER_NAME "msm_sharedmem"
+#define pr_fmt(fmt) DRIVER_NAME ": %s: " fmt, __func__
+
+#include <linux/uio_driver.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/dma-mapping.h>
+
+#define CLIENT_ID_PROP "qcom,client-id"
+
+static int uio_get_mem_index(struct uio_info *info, struct vm_area_struct *vma)
+{
+	if (vma->vm_pgoff >= MAX_UIO_MAPS)
+		return -EINVAL;
+
+	if (info->mem[vma->vm_pgoff].size == 0)
+		return -EINVAL;
+
+	return (int)vma->vm_pgoff;
+}
+
+static int sharedmem_mmap(struct uio_info *info, struct vm_area_struct *vma)
+{
+	int result;
+	struct uio_mem *mem;
+	int mem_index = uio_get_mem_index(info, vma);
+
+	if (mem_index < 0) {
+		pr_err("mem_index is invalid errno %d\n", mem_index);
+		return mem_index;
+	}
+
+	mem = info->mem + mem_index;
+
+	if (vma->vm_end - vma->vm_start > mem->size) {
+		pr_err("vm_end[%lu] - vm_start[%lu] [%lu] > mem->size[%lu]\n",
+			vma->vm_end, vma->vm_start,
+			(vma->vm_end - vma->vm_start), mem->size);
+		return -EINVAL;
+	}
+	pr_debug("Attempting to setup mmap.\n");
+
+	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+
+	result = remap_pfn_range(vma,
+				 vma->vm_start,
+				 mem->addr >> PAGE_SHIFT,
+				 vma->vm_end - vma->vm_start,
+				 vma->vm_page_prot);
+	if (result != 0)
+		pr_err("mmap Failed with errno %d\n", result);
+	else
+		pr_debug("mmap success\n");
+
+	return result;
+}
+
+static int msm_sharedmem_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct uio_info *info = NULL;
+	struct resource *clnt_res = NULL;
+	u32 client_id = ((u32)~0U);
+	u32 shared_mem_size = 0;
+	void *shared_mem = NULL;
+	phys_addr_t shared_mem_pyhsical = 0;
+	bool is_addr_dynamic = false;
+
+	/* Get the addresses from platform-data */
+	if (!pdev->dev.of_node) {
+		pr_err("Node not found\n");
+		ret = -ENODEV;
+		goto out;
+	}
+	clnt_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!clnt_res) {
+		pr_err("resource not found\n");
+		return -ENODEV;
+	}
+
+	ret = of_property_read_u32(pdev->dev.of_node, CLIENT_ID_PROP,
+				   &client_id);
+	if (ret) {
+		client_id = ((u32)~0U);
+		pr_warn("qcom,client-id property not found\n");
+	}
+
+	info = devm_kzalloc(&pdev->dev, sizeof(struct uio_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	shared_mem_size = resource_size(clnt_res);
+	shared_mem_pyhsical = clnt_res->start;
+
+	if (shared_mem_size == 0) {
+		pr_err("Shared memory size is zero\n");
+		return -EINVAL;
+	}
+
+	if (shared_mem_pyhsical == 0) {
+		is_addr_dynamic = true;
+		shared_mem = dma_alloc_coherent(&pdev->dev, shared_mem_size,
+					&shared_mem_pyhsical, GFP_KERNEL);
+		if (shared_mem == NULL)
+			return -ENOMEM;
+	}
+
+	/* Setup device */
+	info->mmap = sharedmem_mmap; /* Custom mmap function. */
+	info->name = clnt_res->name;
+	info->version = "1.0";
+	info->mem[0].addr = shared_mem_pyhsical;
+	info->mem[0].size = shared_mem_size;
+	info->mem[0].memtype = UIO_MEM_PHYS;
+
+	ret = uio_register_device(&pdev->dev, info);
+	if (ret) {
+		pr_err("uio register failed ret=%d\n", ret);
+		goto out;
+	}
+	dev_set_drvdata(&pdev->dev, info);
+
+	pr_info("Device created for client '%s'\n", clnt_res->name);
+out:
+	return ret;
+}
+
+static int msm_sharedmem_remove(struct platform_device *pdev)
+{
+	struct uio_info *info = dev_get_drvdata(&pdev->dev);
+
+	uio_unregister_device(info);
+
+	return 0;
+}
+
+static const struct of_device_id msm_sharedmem_of_match[] = {
+	{.compatible = "qcom,sharedmem-uio",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, msm_sharedmem_of_match);
+
+static struct platform_driver msm_sharedmem_driver = {
+	.probe          = msm_sharedmem_probe,
+	.remove         = msm_sharedmem_remove,
+	.driver         = {
+		.name   = DRIVER_NAME,
+		.of_match_table = msm_sharedmem_of_match,
+	},
+};
+
+
+static int __init msm_sharedmem_init(void)
+{
+	int result;
+
+	result = platform_driver_register(&msm_sharedmem_driver);
+	if (result != 0) {
+		pr_err("Platform driver registration failed\n");
+		return result;
+	}
+	return 0;
+}
+
+static void __exit msm_sharedmem_exit(void)
+{
+	platform_driver_unregister(&msm_sharedmem_driver);
+}
+
+module_init(msm_sharedmem_init);
+module_exit(msm_sharedmem_exit);
+
+MODULE_LICENSE("GPL v2");