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

The Programmable Real-Time Unit - Industrial Communication
Subsystem (PRU-ICSS) is present of various TI SoCs such as
AM335x or AM437x or the AM654x family. Each SoC can have
one or more PRUSS instances that may or may not be identical.

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.

Add support for pruss driver. Currently am654x family
is supported.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210622063431.3151-2-lokeshvutla@ti.com

3 files changed, 229 insertions, 0 deletions

diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig
index e4f8834448..0ee21f9904 100644
--- a/drivers/soc/ti/Kconfig
+++ b/drivers/soc/ti/Kconfig
@@ -23,4 +23,15 @@ config TI_KEYSTONE_SERDES
 	 SerDes driver for Keystone SoC used for ethernet support on TI
 	 K2 platforms.
 
+config TI_PRUSS
+	bool "Support for TI's K3 based Pruss driver"
+	depends on DM
+	depends on ARCH_K3
+	depends on OF_CONTROL
+	depends on SYSCON
+	help
+	  Support for TI PRU-ICSSG subsystem.
+	  Currently supported on AM65xx SoCs Say Y here to support the
+	  Programmable Realtime Unit (PRU).
+
 endif # SOC_TI
diff --git a/drivers/soc/ti/Makefile b/drivers/soc/ti/Makefile
index 4ec04ee125..34f80aad29 100644
--- a/drivers/soc/ti/Makefile
+++ b/drivers/soc/ti/Makefile
@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_TI_K3_NAVSS_RINGACC)	+= k3-navss-ringacc.o
 obj-$(CONFIG_TI_KEYSTONE_SERDES)	+= keystone_serdes.o
+obj-$(CONFIG_TI_PRUSS)	+= pruss.o
diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
new file mode 100644
index 0000000000..461390925d
--- /dev/null
+++ b/drivers/soc/ti/pruss.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PRU-ICSS platform driver for various TI SoCs
+ *
+ * Copyright (C) 2020-2021 Texas Instruments Incorporated - https://www.ti.com/
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/of_access.h>
+#include <errno.h>
+#include <clk.h>
+#include <reset.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/io.h>
+#include <power-domain.h>
+#include <linux/pruss_driver.h>
+#include <dm/device_compat.h>
+
+#define PRUSS_CFG_IEPCLK	0x30
+#define ICSSG_CFG_CORE_SYNC	0x3c
+
+#define ICSSG_TASK_MGR_OFFSET	0x2a000
+
+/* PRUSS_IEPCLK register bits */
+#define PRUSS_IEPCLK_IEP_OCP_CLK_EN		BIT(0)
+
+/* ICSSG CORE_SYNC register bits */
+#define ICSSG_CORE_VBUSP_SYNC_EN		BIT(0)
+
+/*
+ * pruss_request_tm_region() - Request pruss for task manager region
+ * @dev:	corresponding k3 device
+ * @loc:	the task manager physical address
+ *
+ * Return: 0 if all goes good, else appropriate error message.
+ */
+int pruss_request_tm_region(struct udevice *dev, phys_addr_t *loc)
+{
+	struct pruss *priv;
+
+	priv = dev_get_priv(dev);
+	if (!priv || !priv->mem_regions[PRUSS_MEM_DRAM0].pa)
+		return -EINVAL;
+
+	*loc = priv->mem_regions[PRUSS_MEM_DRAM0].pa + ICSSG_TASK_MGR_OFFSET;
+
+	return 0;
+}
+
+/**
+ * pruss_request_mem_region() - request a memory resource
+ * @dev: the pruss device
+ * @mem_id: the memory resource id
+ * @region: pointer to memory region structure to be filled in
+ *
+ * This function allows a client driver to request a memory resource,
+ * and if successful, will let the client driver own the particular
+ * memory region until released using the pruss_release_mem_region()
+ * API.
+ *
+ * Returns the memory region if requested resource is available, an
+ * error otherwise
+ */
+int pruss_request_mem_region(struct udevice *dev, enum pruss_mem mem_id,
+			     struct pruss_mem_region *region)
+{
+	struct pruss *pruss;
+
+	pruss = dev_get_priv(dev);
+	if (!pruss || !region)
+		return -EINVAL;
+
+	if (mem_id >= PRUSS_MEM_MAX)
+		return -EINVAL;
+
+	if (pruss->mem_in_use[mem_id])
+		return -EBUSY;
+
+	*region = pruss->mem_regions[mem_id];
+	pruss->mem_in_use[mem_id] = region;
+
+	return 0;
+}
+
+/**
+ * pruss_release_mem_region() - release a memory resource
+ * @dev: the pruss device
+ * @region: the memory region to release
+ *
+ * This function is the complimentary function to
+ * pruss_request_mem_region(), and allows the client drivers to
+ * release back a memory resource.
+ *
+ * Returns 0 on success, an error code otherwise
+ */
+int pruss_release_mem_region(struct udevice *dev,
+			     struct pruss_mem_region *region)
+{
+	struct pruss *pruss;
+	int id;
+
+	pruss = dev_get_priv(dev);
+	if (!pruss || !region)
+		return -EINVAL;
+
+	/* find out the memory region being released */
+	for (id = 0; id < PRUSS_MEM_MAX; id++) {
+		if (pruss->mem_in_use[id] == region)
+			break;
+	}
+
+	if (id == PRUSS_MEM_MAX)
+		return -EINVAL;
+
+	pruss->mem_in_use[id] = NULL;
+
+	return 0;
+}
+
+/**
+ * pruss_cfg_update() - configure a PRUSS CFG sub-module register
+ * @dev: the pruss device
+ * @reg: register offset within the CFG sub-module
+ * @mask: bit mask to use for programming the @val
+ * @val: value to write
+ *
+ * Programs a given register within the PRUSS CFG sub-module
+ *
+ * Returns 0 on success, or an error code otherwise
+ */
+int pruss_cfg_update(struct udevice *dev, unsigned int reg,
+		     unsigned int mask, unsigned int val)
+{
+	struct pruss *pruss;
+
+	pruss = dev_get_priv(dev);
+	if (IS_ERR_OR_NULL(pruss))
+		return -EINVAL;
+
+	return regmap_update_bits(pruss->cfg, reg, mask, val);
+}
+
+/**
+ * pruss_probe() - Basic probe
+ * @dev:	corresponding k3 device
+ *
+ * Return: 0 if all goes good, else appropriate error message.
+ */
+static int pruss_probe(struct udevice *dev)
+{
+	const char *mem_names[PRUSS_MEM_MAX] = { "dram0", "dram1", "shrdram2" };
+	ofnode sub_node, node, memories;
+	struct udevice *syscon;
+	struct pruss *priv;
+	int ret, idx, i;
+
+	priv = dev_get_priv(dev);
+	node = dev_ofnode(dev);
+	priv->dev = dev;
+	memories = ofnode_find_subnode(node, "memories");
+
+	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
+		idx = ofnode_stringlist_search(memories, "reg-names", mem_names[i]);
+		priv->mem_regions[i].pa = ofnode_get_addr_size_index(memories, idx,
+						       (u64 *)&priv->mem_regions[i].size);
+	}
+
+	sub_node = ofnode_find_subnode(node, "cfg");
+	ret = uclass_get_device_by_ofnode(UCLASS_SYSCON, sub_node,
+					  &syscon);
+
+	priv->cfg = syscon_get_regmap(syscon);
+	if (IS_ERR(priv->cfg)) {
+		dev_err(dev, "unable to get cfg regmap (%ld)\n",
+			PTR_ERR(priv->cfg));
+		return -ENODEV;
+	}
+
+	/*
+	 * ToDo: To be modelled as clocks.
+	 * The CORE block uses two multiplexers to allow software to
+	 * select one of three source clocks (ICSSGn_CORE_CLK, ICSSGn_ICLK or
+	 * ICSSGn_IEP_CLK) for the final clock source of the CORE block.
+	 * The user needs to configure ICSSG_CORE_SYNC_REG[0] CORE_VBUSP_SYNC_EN
+	 * bit & ICSSG_IEPCLK_REG[0] IEP_OCP_CLK_EN bit in order to select the
+	 * clock source to the CORE block.
+	 */
+	ret = regmap_update_bits(priv->cfg, ICSSG_CFG_CORE_SYNC,
+				 ICSSG_CORE_VBUSP_SYNC_EN,
+				 ICSSG_CORE_VBUSP_SYNC_EN);
+	if (ret)
+		return ret;
+	ret = regmap_update_bits(priv->cfg, PRUSS_CFG_IEPCLK,
+				 PRUSS_IEPCLK_IEP_OCP_CLK_EN,
+				 PRUSS_IEPCLK_IEP_OCP_CLK_EN);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "pruss successfully probed %s\n", dev->name);
+
+	return 0;
+}
+
+static const struct udevice_id pruss_ids[] = {
+	{ .compatible = "ti,am654-icssg"},
+	{}
+};
+
+U_BOOT_DRIVER(pruss) = {
+	.name = "pruss",
+	.of_match = pruss_ids,
+	.id = UCLASS_MISC,
+	.probe = pruss_probe,
+	.priv_auto = sizeof(struct pruss),
+};