soc: ti: pruss: Add a platform driver for PRUSS in TI SoCs

The Programmable Real-Time Unit - Industrial Communication
Subsystem (PRU-ICSS) is present on various TI SoCs such as
AM335x or AM437x or the Keystone 66AK2G. Each SoC can have
one or more PRUSS instances that may or may not be identical.
For example, AM335x SoCs have a single PRUSS, while AM437x has
two PRUSS instances PRUSS1 and PRUSS0, with the PRUSS0 being
a cut-down version of the PRUSS1.

The PRUSS consists of dual 32-bit RISC cores called the
Programmable Real-Time Units (PRUs), some shared, data and
instruction memories, some internal peripheral modules, and
an interrupt controller. The programmable nature of the PRUs
provide flexibility to implement custom peripheral interfaces,
fast real-time responses, or specialized data handling.

The PRU-ICSS functionality is achieved through three different
platform drivers addressing a specific portion of the PRUSS.
Some sub-modules of the PRU-ICSS IP reuse some of the existing
drivers (like davinci mdio driver or the generic syscon driver).
This design provides flexibility in representing the different
modules of PRUSS accordingly, and at the same time allowing the
PRUSS driver to add some instance specific configuration within
an SoC.

The PRUSS platform driver deals with the overall PRUSS and is
used for managing the subsystem level resources like various
memories and the CFG module. It is responsible for the creation
and deletion of the platform devices for the child PRU devices
and other child devices (like Interrupt Controller, MDIO node
and some syscon nodes) so that they can be managed by specific
platform drivers. The PRUSS interrupt controller is managed by
an irqchip driver, while the individual PRU RISC cores are
managed by a PRU remoteproc driver.

The driver currently supports the AM335x SoC, and support for
other TI SoCs will be added in subsequent patches.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

drivers/soc/ti/Kconfig

@@ -101,6 +101,17 @@ config TI_K3_SOCINFO
 	  platforms to provide information about the SoC family and
 	  variant to user space.
 
+config TI_PRUSS
+	tristate "TI PRU-ICSS Subsystem Platform drivers"
+	depends on SOC_AM33XX
+	select MFD_SYSCON
+	help
+	  TI PRU-ICSS Subsystem platform specific support.
+
+	  Say Y or M here to support the Programmable Realtime Unit (PRU)
+	  processors on various TI SoCs. It's safe to say N here if you're
+	  not interested in the PRU or if you are unsure.
+
 endif # SOC_TI
 
 config TI_SCI_INTA_MSI_DOMAIN

drivers/soc/ti/Makefile

@@ -12,3 +12,4 @@ obj-$(CONFIG_TI_SCI_PM_DOMAINS)		+= ti_sci_pm_domains.o
 obj-$(CONFIG_TI_SCI_INTA_MSI_DOMAIN)	+= ti_sci_inta_msi.o
 obj-$(CONFIG_TI_K3_RINGACC)		+= k3-ringacc.o
 obj-$(CONFIG_TI_K3_SOCINFO)		+= k3-socinfo.o
+obj-$(CONFIG_TI_PRUSS)			+= pruss.o

drivers/soc/ti/pruss.c

@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PRU-ICSS platform driver for various TI SoCs
+ *
+ * Copyright (C) 2014-2020 Texas Instruments Incorporated - http://www.ti.com/
+ * Author(s):
+ *	Suman Anna <s-anna@ti.com>
+ *	Andrew F. Davis <afd@ti.com>
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pruss_driver.h>
+
+static int pruss_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev_of_node(dev);
+	struct device_node *child;
+	struct pruss *pruss;
+	struct resource res;
+	int ret, i, index;
+	const char *mem_names[PRUSS_MEM_MAX] = { "dram0", "dram1", "shrdram2" };
+
+	ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
+	if (ret) {
+		dev_err(dev, "failed to set the DMA coherent mask");
+		return ret;
+	}
+
+	pruss = devm_kzalloc(dev, sizeof(*pruss), GFP_KERNEL);
+	if (!pruss)
+		return -ENOMEM;
+
+	pruss->dev = dev;
+
+	child = of_get_child_by_name(np, "memories");
+	if (!child) {
+		dev_err(dev, "%pOF is missing its 'memories' node\n", child);
+		return -ENODEV;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
+		index = of_property_match_string(child, "reg-names",
+						 mem_names[i]);
+		if (index < 0) {
+			of_node_put(child);
+			return index;
+		}
+
+		if (of_address_to_resource(child, index, &res)) {
+			of_node_put(child);
+			return -EINVAL;
+		}
+
+		pruss->mem_regions[i].va = devm_ioremap(dev, res.start,
+							resource_size(&res));
+		if (!pruss->mem_regions[i].va) {
+			dev_err(dev, "failed to parse and map memory resource %d %s\n",
+				i, mem_names[i]);
+			of_node_put(child);
+			return -ENOMEM;
+		}
+		pruss->mem_regions[i].pa = res.start;
+		pruss->mem_regions[i].size = resource_size(&res);
+
+		dev_dbg(dev, "memory %8s: pa %pa size 0x%zx va %pK\n",
+			mem_names[i], &pruss->mem_regions[i].pa,
+			pruss->mem_regions[i].size, pruss->mem_regions[i].va);
+	}
+	of_node_put(child);
+
+	platform_set_drvdata(pdev, pruss);
+
+	pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "couldn't enable module\n");
+		pm_runtime_put_noidle(dev);
+		goto rpm_disable;
+	}
+
+	child = of_get_child_by_name(np, "cfg");
+	if (!child) {
+		dev_err(dev, "%pOF is missing its 'cfg' node\n", child);
+		ret = -ENODEV;
+		goto rpm_put;
+	}
+
+	pruss->cfg_regmap = syscon_node_to_regmap(child);
+	of_node_put(child);
+	if (IS_ERR(pruss->cfg_regmap)) {
+		ret = -ENODEV;
+		goto rpm_put;
+	}
+
+	ret = devm_of_platform_populate(dev);
+	if (ret) {
+		dev_err(dev, "failed to register child devices\n");
+		goto rpm_put;
+	}
+
+	return 0;
+
+rpm_put:
+	pm_runtime_put_sync(dev);
+rpm_disable:
+	pm_runtime_disable(dev);
+	return ret;
+}
+
+static int pruss_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	devm_of_platform_depopulate(dev);
+
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+
+	return 0;
+}
+
+static const struct of_device_id pruss_of_match[] = {
+	{ .compatible = "ti,am3356-pruss" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, pruss_of_match);
+
+static struct platform_driver pruss_driver = {
+	.driver = {
+		.name = "pruss",
+		.of_match_table = pruss_of_match,
+	},
+	.probe  = pruss_probe,
+	.remove = pruss_remove,
+};
+module_platform_driver(pruss_driver);
+
+MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
+MODULE_DESCRIPTION("PRU-ICSS Subsystem Driver");
+MODULE_LICENSE("GPL v2");

include/linux/pruss_driver.h

@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * PRU-ICSS sub-system specific definitions
+ *
+ * Copyright (C) 2014-2020 Texas Instruments Incorporated - http://www.ti.com/
+ *	Suman Anna <s-anna@ti.com>
+ */
+
+#ifndef _PRUSS_DRIVER_H_
+#define _PRUSS_DRIVER_H_
+
+#include <linux/types.h>
+
+/*
+ * enum pruss_mem - PRUSS memory range identifiers
+ */
+enum pruss_mem {
+	PRUSS_MEM_DRAM0 = 0,
+	PRUSS_MEM_DRAM1,
+	PRUSS_MEM_SHRD_RAM2,
+	PRUSS_MEM_MAX,
+};
+
+/**
+ * struct pruss_mem_region - PRUSS memory region structure
+ * @va: kernel virtual address of the PRUSS memory region
+ * @pa: physical (bus) address of the PRUSS memory region
+ * @size: size of the PRUSS memory region
+ */
+struct pruss_mem_region {
+	void __iomem *va;
+	phys_addr_t pa;
+	size_t size;
+};
+
+/**
+ * struct pruss - PRUSS parent structure
+ * @dev: pruss device pointer
+ * @cfg_regmap: regmap for config region
+ * @mem_regions: data for each of the PRUSS memory regions
+ */
+struct pruss {
+	struct device *dev;
+	struct regmap *cfg_regmap;
+	struct pruss_mem_region mem_regions[PRUSS_MEM_MAX];
+};
+
+#endif	/* _PRUSS_DRIVER_H_ */