[PATCH v2 2/6] soc: ti: pruss: Add pruss_{request,release}_mem_region() API

Puranjay Mohan
2022-04-18T12:37:52Z

From: "Andrew F. Davis" <afd@ti.com>

Add two new API - pruss_request_mem_region() & pruss_release_mem_region(),
to the PRUSS platform driver to allow client drivers to acquire and release
the common memory resources present within a PRU-ICSS subsystem. This
allows the client drivers to directly manipulate the respective memories,
as per their design contract with the associated firmware.

Co-developed-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Signed-off-by: Puranjay Mohan <p-mohan@ti.com>
---
drivers/soc/ti/pruss.c | 77 ++++++++++++++++++++++++++++++++++++
include/linux/pruss.h | 39 ++++++++++++++++++
include/linux/pruss_driver.h | 27 +++----------
3 files changed, 121 insertions(+), 22 deletions(-)

diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
index fb0a0b4a9663..95c0cbd7c52f 100644
--- a/drivers/soc/ti/pruss.c
+++ b/drivers/soc/ti/pruss.c
@@ -88,6 +88,82 @@ void pruss_put(struct pruss *pruss)
}
EXPORT_SYMBOL_GPL(pruss_put);

+/**
+ * pruss_request_mem_region() - request a memory resource
+ * @pruss: the pruss instance
+ * @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.
+ *
+ * Return: 0 if requested memory region is available (in such case pointer to
+ * memory region is returned via @region), an error otherwise
+ */
+int pruss_request_mem_region(struct pruss *pruss, enum pruss_mem mem_id,
+ struct pruss_mem_region *region)
+{
+ if (!pruss || !region || mem_id >= PRUSS_MEM_MAX)
+ return -EINVAL;
+
+ mutex_lock(&pruss->lock);
+
+ if (pruss->mem_in_use[mem_id]) {
+ mutex_unlock(&pruss->lock);
+ return -EBUSY;
+ }
+
+ *region = pruss->mem_regions[mem_id];
+ pruss->mem_in_use[mem_id] = region;
+
+ mutex_unlock(&pruss->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pruss_request_mem_region);
+
+/**
+ * pruss_release_mem_region() - release a memory resource
+ * @pruss: the pruss instance
+ * @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.
+ *
+ * Return: 0 on success, an error code otherwise
+ */
+int pruss_release_mem_region(struct pruss *pruss,
+ struct pruss_mem_region *region)
+{
+ int id;
+
+ if (!pruss || !region)
+ return -EINVAL;
+
+ mutex_lock(&pruss->lock);
+
+ /* 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) {
+ mutex_unlock(&pruss->lock);
+ return -EINVAL;
+ }
+
+ pruss->mem_in_use[id] = NULL;
+
+ mutex_unlock(&pruss->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pruss_release_mem_region);
+
static void pruss_of_free_clk_provider(void *data)
{
struct device_node *clk_mux_np = data;
@@ -290,6 +366,7 @@ static int pruss_probe(struct platform_device *pdev)
return -ENOMEM;

pruss->dev = dev;
+ mutex_init(&pruss->lock);

child = of_get_child_by_name(np, "memories");
if (!child) {
diff --git a/include/linux/pruss.h b/include/linux/pruss.h
index 23d556e0dd72..689ef243bcbc 100644
--- a/include/linux/pruss.h
+++ b/include/linux/pruss.h
@@ -39,6 +39,28 @@ enum pru_ctable_idx {
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 device_node;
struct rproc;
struct pruss;
@@ -47,6 +69,10 @@ struct pruss;

struct pruss *pruss_get(struct rproc *rproc);
void pruss_put(struct pruss *pruss);
+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);

#else

@@ -57,6 +83,19 @@ static inline struct pruss *pruss_get(struct rproc *rproc)

static inline void pruss_put(struct pruss *pruss) { }

+static inline int pruss_request_mem_region(struct pruss *pruss,
+ enum pruss_mem mem_id,
+ struct pruss_mem_region *region)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int pruss_release_mem_region(struct pruss *pruss,
+ struct pruss_mem_region *region)
+{
+ return -EOPNOTSUPP;
+}
+
#endif /* CONFIG_TI_PRUSS */

#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
diff --git a/include/linux/pruss_driver.h b/include/linux/pruss_driver.h
index d054d2179d82..e2d5477225c6 100644
--- a/include/linux/pruss_driver.h
+++ b/include/linux/pruss_driver.h
@@ -9,37 +9,18 @@
#ifndef _PRUSS_DRIVER_H_
#define _PRUSS_DRIVER_H_

+#include <linux/mutex.h>
#include <linux/pruss.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_base: base iomap for CFG region
* @cfg_regmap: 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
+ * @lock: mutex to serialize access to resources
* @core_clk_mux: clk handle for PRUSS CORE_CLK_MUX
* @iep_clk_mux: clk handle for PRUSS IEP_CLK_MUX
*/
@@ -48,6 +29,8 @@ struct pruss {
void __iomem *cfg_base;
struct regmap *cfg_regmap;
struct pruss_mem_region mem_regions[PRUSS_MEM_MAX];
+ struct pruss_mem_region *mem_in_use[PRUSS_MEM_MAX];
+ struct mutex lock; /* PRU resource lock */
struct clk *core_clk_mux;
struct clk *iep_clk_mux;
};
--
2.17.1