[RFC 08/13] soc: ti: pruss: Add pruss_cfg_read()/update() API

[Puranjay Mohan]

From: Suman Anna <s-anna@xxxxxx>

Add two new generic API pruss_cfg_read() and pruss_cfg_update() to
the PRUSS platform driver to allow other drivers to read and program
respectively a register within the PRUSS CFG sub-module represented
by a syscon driver. This interface provides a simple way for client
drivers without having them to include and parse the CFG syscon node
within their respective device nodes. Various useful registers and
macros for certain register bit-fields and their values have also
been added.

It is the responsibility of the client drivers to reconfigure or
reset a particular register upon any failures.

Signed-off-by: Suman Anna <s-anna@xxxxxx>
Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx>
Signed-off-by: Puranjay Mohan <p-mohan@xxxxxx>
---
 drivers/soc/ti/pruss.c |  41 +++++++++++++++++
 include/linux/pruss.h  | 102 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 143 insertions(+)

diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
index bda920662de2..9ef15daa405a 100644
--- a/drivers/soc/ti/pruss.c
+++ b/drivers/soc/ti/pruss.c
@@ -164,6 +164,47 @@ int pruss_release_mem_region(struct pruss *pruss,
 }
 EXPORT_SYMBOL_GPL(pruss_release_mem_region);
 
+/**
+ * pruss_cfg_read() - read a PRUSS CFG sub-module register
+ * @pruss: the pruss instance handle
+ * @reg: register offset within the CFG sub-module
+ * @val: pointer to return the value in
+ *
+ * Reads a given register within the PRUSS CFG sub-module and
+ * returns it through the passed-in @val pointer
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+int pruss_cfg_read(struct pruss *pruss, unsigned int reg, unsigned int *val)
+{
+	if (IS_ERR_OR_NULL(pruss))
+		return -EINVAL;
+
+	return regmap_read(pruss->cfg_regmap, reg, val);
+}
+EXPORT_SYMBOL_GPL(pruss_cfg_read);
+
+/**
+ * pruss_cfg_update() - configure a PRUSS CFG sub-module register
+ * @pruss: the pruss instance handle
+ * @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
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+int pruss_cfg_update(struct pruss *pruss, unsigned int reg,
+		     unsigned int mask, unsigned int val)
+{
+	if (IS_ERR_OR_NULL(pruss))
+		return -EINVAL;
+
+	return regmap_update_bits(pruss->cfg_regmap, reg, mask, val);
+}
+EXPORT_SYMBOL_GPL(pruss_cfg_update);
+
 static void pruss_of_free_clk_provider(void *data)
 {
 	struct device_node *clk_mux_np = data;
diff --git a/include/linux/pruss.h b/include/linux/pruss.h
index 689ef243bcbc..eb2f974eef9c 100644
--- a/include/linux/pruss.h
+++ b/include/linux/pruss.h
@@ -10,12 +10,99 @@
 #ifndef __LINUX_PRUSS_H
 #define __LINUX_PRUSS_H
 
+#include <linux/bits.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/types.h>
 
 #define PRU_RPROC_DRVNAME "pru-rproc"
 
+/*
+ * 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_XFER_SHIFT_EN			BIT(1)
+#define PRUSS_SPP_PRU1_PAD_HP_EN		BIT(0)
+
+/*
+ * 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
  */
@@ -73,6 +160,9 @@ int pruss_request_mem_region(struct pruss *pruss, enum pruss_mem mem_id,
 			     struct pruss_mem_region *region);
 int pruss_release_mem_region(struct pruss *pruss,
 			     struct pruss_mem_region *region);
+int pruss_cfg_read(struct pruss *pruss, unsigned int reg, unsigned int *val);
+int pruss_cfg_update(struct pruss *pruss, unsigned int reg,
+		     unsigned int mask, unsigned int val);
 
 #else
 
@@ -96,6 +186,18 @@ static inline int pruss_release_mem_region(struct pruss *pruss,
 	return -EOPNOTSUPP;
 }
 
+static inline int pruss_cfg_read(struct pruss *pruss, unsigned int reg,
+				 unsigned int *val)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int pruss_cfg_update(struct pruss *pruss, unsigned int reg,
+				   unsigned int mask, unsigned int val)
+{
+	return -EOPNOTSUPP;
+}
+
 #endif /* CONFIG_TI_PRUSS */
 
 #if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
-- 
2.17.1