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
diff --git a/include/linux/pruss_driver.h b/include/linux/pruss_driver.h
new file mode 100644
index 0000000..25272e8
--- /dev/null
+++ b/include/linux/pruss_driver.h
@@ -0,0 +1,227 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef __TI_PRUSS_H
+#define __TI_PRUSS_H
+
+/*
+ * PRU_ICSS_CFG registers
+ * SYSCFG, ISRP, ISP, IESP, IECP, SCRP applicable on AMxxxx devices only
+ */
+#define PRUSS_CFG_REVID		0x00
+#define PRUSS_CFG_SYSCFG	0x04
+#define PRUSS_CFG_GPCFG(x)	(0x08 + (x) * 4)
+#define PRUSS_CFG_CGR		0x10
+#define PRUSS_CFG_ISRP		0x14
+#define PRUSS_CFG_ISP		0x18
+#define PRUSS_CFG_IESP		0x1C
+#define PRUSS_CFG_IECP		0x20
+#define PRUSS_CFG_SCRP		0x24
+#define PRUSS_CFG_PMAO		0x28
+#define PRUSS_CFG_MII_RT	0x2C
+#define PRUSS_CFG_IEPCLK	0x30
+#define PRUSS_CFG_SPP		0x34
+#define PRUSS_CFG_PIN_MX	0x40
+
+/* PRUSS_GPCFG register bits */
+#define PRUSS_GPCFG_PRU_GPO_SH_SEL		BIT(25)
+
+#define PRUSS_GPCFG_PRU_DIV1_SHIFT		20
+#define PRUSS_GPCFG_PRU_DIV1_MASK		GENMASK(24, 20)
+
+#define PRUSS_GPCFG_PRU_DIV0_SHIFT		15
+#define PRUSS_GPCFG_PRU_DIV0_MASK		GENMASK(15, 19)
+
+#define PRUSS_GPCFG_PRU_GPO_MODE		BIT(14)
+#define PRUSS_GPCFG_PRU_GPO_MODE_DIRECT		0
+#define PRUSS_GPCFG_PRU_GPO_MODE_SERIAL		BIT(14)
+
+#define PRUSS_GPCFG_PRU_GPI_SB			BIT(13)
+
+#define PRUSS_GPCFG_PRU_GPI_DIV1_SHIFT		8
+#define PRUSS_GPCFG_PRU_GPI_DIV1_MASK		GENMASK(12, 8)
+
+#define PRUSS_GPCFG_PRU_GPI_DIV0_SHIFT		3
+#define PRUSS_GPCFG_PRU_GPI_DIV0_MASK		GENMASK(7, 3)
+
+#define PRUSS_GPCFG_PRU_GPI_CLK_MODE_POSITIVE	0
+#define PRUSS_GPCFG_PRU_GPI_CLK_MODE_NEGATIVE	BIT(2)
+#define PRUSS_GPCFG_PRU_GPI_CLK_MODE		BIT(2)
+
+#define PRUSS_GPCFG_PRU_GPI_MODE_MASK		GENMASK(1, 0)
+#define PRUSS_GPCFG_PRU_GPI_MODE_SHIFT		0
+
+#define PRUSS_GPCFG_PRU_MUX_SEL_SHIFT		26
+#define PRUSS_GPCFG_PRU_MUX_SEL_MASK		GENMASK(29, 26)
+
+/* PRUSS_MII_RT register bits */
+#define PRUSS_MII_RT_EVENT_EN			BIT(0)
+
+/* PRUSS_SPP register bits */
+#define PRUSS_SPP_PRU1_PAD_HP_EN		BIT(0)
+#define PRUSS_SPP_XFER_SHIFT_EN			BIT(1)
+#define PRUSS_SPP_XFR_BYTE_SHIFT_EN		BIT(2)
+#define PRUSS_SPP_RTU_XFR_SHIFT_EN		BIT(3)
+
+/**
+ * enum pruss_gp_mux_sel - PRUSS GPI/O Mux modes for the
+ * PRUSS_GPCFG0/1 registers
+ *
+ * NOTE: The below defines are the most common values, but there
+ * are some exceptions like on 66AK2G, where the RESERVED and MII2
+ * values are interchanged. Also, this bit-field does not exist on
+ * AM335x SoCs
+ */
+enum pruss_gp_mux_sel {
+	PRUSS_GP_MUX_SEL_GP = 0,
+	PRUSS_GP_MUX_SEL_ENDAT,
+	PRUSS_GP_MUX_SEL_RESERVED,
+	PRUSS_GP_MUX_SEL_SD,
+	PRUSS_GP_MUX_SEL_MII2,
+	PRUSS_GP_MUX_SEL_MAX,
+};
+
+/**
+ * enum pruss_gpi_mode - PRUSS GPI configuration modes, used
+ *			 to program the PRUSS_GPCFG0/1 registers
+ */
+enum pruss_gpi_mode {
+	PRUSS_GPI_MODE_DIRECT = 0,
+	PRUSS_GPI_MODE_PARALLEL,
+	PRUSS_GPI_MODE_28BIT_SHIFT,
+	PRUSS_GPI_MODE_MII,
+};
+
+/**
+ * enum pruss_pru_id - PRU core identifiers
+ */
+enum pruss_pru_id {
+	PRUSS_PRU0 = 0,
+	PRUSS_PRU1,
+	PRUSS_NUM_PRUS,
+};
+
+/**
+ * enum pru_ctable_idx - Configurable Constant table index identifiers
+ */
+enum pru_ctable_idx {
+	PRU_C24 = 0,
+	PRU_C25,
+	PRU_C26,
+	PRU_C27,
+	PRU_C28,
+	PRU_C29,
+	PRU_C30,
+	PRU_C31,
+};
+
+/**
+ * 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 for config region
+ * @mem_regions: data for each of the PRUSS memory regions
+ * @mem_in_use: to indicate if memory resource is in use
+ */
+struct pruss {
+	struct udevice *dev;
+	struct regmap *cfg;
+	struct pruss_mem_region mem_regions[PRUSS_MEM_MAX];
+	struct pruss_mem_region *mem_in_use[PRUSS_MEM_MAX];
+};
+
+int pruss_request_tm_region(struct udevice *dev, phys_addr_t *loc);
+int pruss_request_mem_region(struct udevice *dev, enum pruss_mem mem_id,
+			     struct pruss_mem_region *region);
+int pruss_release_mem_region(struct udevice *dev, struct pruss_mem_region *region);
+int pruss_cfg_update(struct udevice *dev, unsigned int reg,
+		     unsigned int mask, unsigned int val);
+
+/**
+ * pruss_cfg_gpimode() - set the GPI mode of the PRU
+ * @dev: the pruss device
+ * @pru_id: the rproc instance handle of the PRU
+ * @mode: GPI mode to set
+ *
+ * Sets the GPI mode for a given PRU by programming the
+ * corresponding PRUSS_CFG_GPCFGx register
+ *
+ * Returns 0 on success, or an error code otherwise
+ */
+static inline int pruss_cfg_gpimode(struct udevice *dev, enum pruss_pru_id id,
+				    enum pruss_gpi_mode mode)
+{
+	if (id < 0)
+		return -EINVAL;
+
+	return pruss_cfg_update(dev, PRUSS_CFG_GPCFG(id),
+				PRUSS_GPCFG_PRU_GPI_MODE_MASK,
+				mode << PRUSS_GPCFG_PRU_GPI_MODE_SHIFT);
+}
+
+/**
+ * pruss_cfg_miirt_enable() - Enable/disable MII RT Events
+ * @dev: the pruss device
+ * @enable: enable/disable
+ *
+ * Enable/disable the MII RT Events for the PRUSS.
+ */
+static inline int pruss_cfg_miirt_enable(struct udevice *dev, bool enable)
+{
+	u32 set = enable ? PRUSS_MII_RT_EVENT_EN : 0;
+
+	return pruss_cfg_update(dev, PRUSS_CFG_MII_RT,
+				PRUSS_MII_RT_EVENT_EN, set);
+}
+
+/**
+ * pruss_cfg_xfr_enable() - Enable/disable XIN XOUT shift functionality
+ * @dev: the pruss device
+ * @enable: enable/disable
+ */
+static inline int pruss_cfg_xfr_enable(struct udevice *dev, bool enable)
+{
+	u32 set = enable ? PRUSS_SPP_XFER_SHIFT_EN : 0;
+
+	return pruss_cfg_update(dev, PRUSS_CFG_SPP,
+			PRUSS_SPP_XFER_SHIFT_EN, set);
+}
+
+/**
+ * pruss_cfg_set_gpmux() - set the GPMUX value for a PRU device
+ * @pruss: pruss device
+ * @pru_id: PRU identifier (0-1)
+ * @mux: new mux value for PRU
+ */
+static inline int pruss_cfg_set_gpmux(struct udevice *dev,
+				      enum pruss_pru_id id, u8 mux)
+{
+	if (mux >= PRUSS_GP_MUX_SEL_MAX)
+		return -EINVAL;
+
+	return pruss_cfg_update(dev, PRUSS_CFG_GPCFG(id),
+			PRUSS_GPCFG_PRU_MUX_SEL_MASK,
+			(u32)mux << PRUSS_GPCFG_PRU_MUX_SEL_SHIFT);
+}
+
+#endif /* __TI_PRUSS_H */