[PATCH v2 11/14] remoteproc/pru: Add pru_rproc_set_ctable() and pru_rproc_set_gpimode()

[Roger Quadros <rogerq@ti.com>]

Some firmwares expect the OS drivers to configure the CTABLE
entries publishing dynamically allocated memory regions. For
example, the PRU Ethernet firmwares use the C28 and C30 entries
for retrieving the Shared RAM and System SRAM (OCMC) areas
allocated by the PRU Ethernet client driver.

Provide a way for users to do that through a new API,
pru_rproc_set_ctable(). The API returns 0 on success and
a negative value on error.

NOTE:
The programmable CTABLE entries are typically re-programmed by
the PRU firmwares when dealing with a certain block of memory
during block processing. This API provides an interface to the
PRU client drivers to publish a dynamically allocated memory
block with the PRU firmware using a CTABLE entry instead of a
negotiated address in shared memory. Additional synchronization
may be needed between the PRU client drivers and firmwares if
different addresses needs to be published at run-time reusing
the same CTABLE entry.

Some client drivers need to set the GPI mode of the
PRU. The GPI mode select bits like in the GPCFG register
space. Add pru_rproc_set_gpimode() API to set the GPI
mode for the PRU.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
[s-anna@ti.com: add the NOTE: on patch description, minor cleanups]
Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/remoteproc/pru_rproc.c       | 48 ++++++++++++++++++++++++++++++++++++
 include/linux/remoteproc/pru_rproc.h | 30 ++++++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
index ddd4b64..85463f7 100644
--- a/drivers/remoteproc/pru_rproc.c
+++ b/drivers/remoteproc/pru_rproc.c
@@ -398,6 +398,54 @@ void pru_rproc_put(struct rproc *rproc)
 }
 EXPORT_SYMBOL_GPL(pru_rproc_put);
 
+/**
+ * pru_rproc_set_ctable() - set the constant table index for the PRU
+ * @rproc: the rproc instance of the PRU
+ * @c: constant table index to set
+ * @addr: physical address to set it to
+ */
+int pru_rproc_set_ctable(struct rproc *rproc, enum pru_ctable_idx c, u32 addr)
+{
+	struct pru_rproc *pru = rproc->priv;
+	unsigned int reg;
+	u32 mask, set;
+	u16 idx;
+	u16 idx_mask;
+
+	/* pointer is 16 bit and index is 8-bit so mask out the rest */
+	idx_mask = (c >= PRU_C28) ? 0xFFFF : 0xFF;
+
+	/* ctable uses bit 8 and upwards only */
+	idx = (addr >> 8) & idx_mask;
+
+	/* configurable ctable (i.e. C24) starts at PRU_CTRL_CTBIR0 */
+	reg = PRU_CTRL_CTBIR0 + 4 * (c >> 1);
+	mask = idx_mask << (16 * (c & 1));
+	set = idx << (16 * (c & 1));
+
+	regmap_update_bits(pru->ctrl_regmap, reg, mask, set);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pru_rproc_set_ctable);
+
+/**
+ * pru_rproc_set_gpimode() - set the GPI mode for the PRU
+ * @rproc: the rproc instance of the PRU
+ * @mode: GPI mode to set
+ *
+ * Returns 0 on success, negative error value otherwise.
+ */
+int pru_rproc_set_gpimode(struct rproc *rproc, enum pruss_gpi_mode mode)
+{
+	struct pru_rproc *pru = rproc->priv;
+
+	return regmap_update_bits(pru->cfg, pru->gpcfg_reg,
+				  PRUSS_GPCFG_PRU_GPI_MODE_MASK,
+				  mode << PRUSS_GPCFG_PRU_GPI_MODE_SHIFT);
+}
+EXPORT_SYMBOL_GPL(pru_rproc_set_gpimode);
+
 /*
  * Control PRU single-step mode
  *
diff --git a/include/linux/remoteproc/pru_rproc.h b/include/linux/remoteproc/pru_rproc.h
index 841da09..887d996 100644
--- a/include/linux/remoteproc/pru_rproc.h
+++ b/include/linux/remoteproc/pru_rproc.h
@@ -8,10 +8,28 @@
 #ifndef __LINUX_REMOTEPROC_PRU_RPROC_H
 #define __LINUX_REMOTEPROC_PRU_RPROC_H
 
+/**
+ * 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_gpi_mode;
+
 #if IS_ENABLED(CONFIG_PRUSS_REMOTEPROC)
 
 struct rproc *pru_rproc_get(struct device_node *node, int index);
 void pru_rproc_put(struct rproc *rproc);
+int pru_rproc_set_ctable(struct rproc *rproc, enum pru_ctable_idx c, u32 addr);
+int pru_rproc_set_gpimode(struct rproc *rproc, enum pruss_gpi_mode mode);
 
 #else
 
@@ -22,6 +40,18 @@ static inline struct rproc *pru_rproc_get(struct device_node *node, int index)
 
 static inline void pru_rproc_put(struct rproc *rproc) { }
 
+static inline int pru_rproc_set_ctable(struct rproc *rproc,
+				       enum pru_ctable_idx c, u32 addr)
+{
+	return -ENOTSUPP;
+}
+
+static inline int pru_rproc_set_gpimode(struct rproc *rproc,
+					enum pruss_gpi_mode mode)
+{
+	return -ENOTSUPP;
+}
+
 #endif /* CONFIG_PRUSS_REMOTEPROC */
 
 #endif /* __LINUX_REMOTEPROC_PRU_RPROC_H */
-- 
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