Re: [PATCH v5 2/6] remoteproc: pru: Add APIs to get and put the PRU cores
From: Md Danish Anwar
Date: Fri Sep 02 2022 - 05:39:29 EST
Hi Mathieu,
On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
+Danish
Hi Mathieu,
On 14/07/22 22:50, Mathieu Poirier wrote:
On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
Hi Puranjay,
Removed Puranjay (as he is no longer with TI) and adding Danish.
Regards,
Kishon
On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
From: Tero Kristo <t-kristo@xxxxxx>
Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
driver to allow client drivers to acquire and release the remoteproc
device associated with a PRU core. The PRU cores are treated as
resources with only one client owning it at a time.
The pru_rproc_get() function returns the rproc handle corresponding
to a PRU core identified by the device tree "ti,prus" property under
the client node. The pru_rproc_put() is the complementary function
to pru_rproc_get().
Co-developed-by: Suman Anna <s-anna@xxxxxx>
Signed-off-by: Suman Anna <s-anna@xxxxxx>
Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx>
Co-developed-by: Puranjay Mohan <p-mohan@xxxxxx>
Signed-off-by: Puranjay Mohan <p-mohan@xxxxxx>
---
drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
include/linux/pruss.h | 56 +++++++++++++
2 files changed, 189 insertions(+), 5 deletions(-)
create mode 100644 include/linux/pruss.h
diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
index 1777a01fa84e..7a35b400287a 100644
--- a/drivers/remoteproc/pru_rproc.c
+++ b/drivers/remoteproc/pru_rproc.c
@@ -2,12 +2,13 @@
/*
* PRU-ICSS remoteproc driver for various TI SoCs
*
- * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
+ * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
*
* Author(s):
* Suman Anna <s-anna@xxxxxx>
* Andrew F. Davis <afd@xxxxxx>
* Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx> for Texas Instruments
+ * Puranjay Mohan <p-mohan@xxxxxx>
*/
#include <linux/bitops.h>
@@ -16,6 +17,7 @@
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
+#include <linux/pruss.h>
#include <linux/pruss_driver.h>
#include <linux/remoteproc.h>
@@ -111,6 +113,8 @@ struct pru_private_data {
* @rproc: remoteproc pointer for this PRU core
* @data: PRU core specific data
* @mem_regions: data for each of the PRU memory regions
+ * @client_np: client device node
+ * @lock: mutex to protect client usage
* @fw_name: name of firmware image used during loading
* @mapped_irq: virtual interrupt numbers of created fw specific mapping
* @pru_interrupt_map: pointer to interrupt mapping description (firmware)
@@ -126,6 +130,8 @@ struct pru_rproc {
struct rproc *rproc;
const struct pru_private_data *data;
struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
+ struct device_node *client_np;
+ struct mutex lock; /* client access lock */
const char *fw_name;
unsigned int *mapped_irq;
struct pru_irq_rsc *pru_interrupt_map;
@@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
}
+static struct rproc *__pru_rproc_get(struct device_node *np, int index)
+{
+ struct device_node *rproc_np = NULL;
+ struct platform_device *pdev;
+ struct rproc *rproc;
+
+ rproc_np = of_parse_phandle(np, "ti,prus", index);
+ if (!rproc_np || !of_device_is_available(rproc_np))
+ return ERR_PTR(-ENODEV);
+
+ pdev = of_find_device_by_node(rproc_np);
+ of_node_put(rproc_np);
+
+ if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
+ /* probably PRU not yet probed */
+ return ERR_PTR(-EPROBE_DEFER);
+
+ /* make sure it is PRU rproc */
+ if (!is_pru_rproc(&pdev->dev)) {
+ put_device(&pdev->dev);
+ return ERR_PTR(-ENODEV);
+ }
+
+ rproc = platform_get_drvdata(pdev);
+ put_device(&pdev->dev);
+ if (!rproc)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ get_device(&rproc->dev);
+
+ return rproc;
+}
+
+/**
+ * pru_rproc_get() - get the PRU rproc instance from a device node
+ * @np: the user/client device node
+ * @index: index to use for the ti,prus property
+ * @pru_id: optional pointer to return the PRU remoteproc processor id
+ *
+ * This function looks through a client device node's "ti,prus" property at
+ * index @index and returns the rproc handle for a valid PRU remote processor if
+ * found. The function allows only one user to own the PRU rproc resource at a
+ * time. Caller must call pru_rproc_put() when done with using the rproc, not
+ * required if the function returns a failure.
+ *
+ * When optional @pru_id pointer is passed the PRU remoteproc processor id is
+ * returned.
+ *
+ * Return: rproc handle on success, and an ERR_PTR on failure using one
+ * of the following error values
+ * -ENODEV if device is not found
+ * -EBUSY if PRU is already acquired by anyone
+ * -EPROBE_DEFER is PRU device is not probed yet
+ */
+struct rproc *pru_rproc_get(struct device_node *np, int index,
+ enum pruss_pru_id *pru_id)
+{
+ struct rproc *rproc;
+ struct pru_rproc *pru;
+ struct device *dev;
+
+ try_module_get(THIS_MODULE);
There should be a module_put() in pru_rproc_put()...
... and in the error path of this function.
More comments to come tomorrow. I'm especially worried about this API racing
with a remote processor being removed or detached.
Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
rproc_get_by_handle() here and that would make sure the remote processor doesn't
go away before the end of the function.
More comments to come...
It is possible to call rproc_get_by_handle() here instead of
__pru_get_proc(), but that would not provide multiple functionality.
The API rproc_get_by_handle() returns rproc handle on success, and NULL
on failure where as __pru_get_proc() returns ERR_PTR on failure which
provides multiple functionality and opportunity for us to distinguish
between multiple errors.
So we have these three options.
1. If we're using the API rproc_get_by_handle() and we want the multiple
ERR_PTR on failure then we will need to change the API
rproc_get_by_handle() and also all the functions that uses
rproc_get_by_handle().
2. Keep the API rproc_get_by_handle() as it is. That will restrict us
from using multiple ERR_PTR on different kinds of error.
3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc().
This will make sure we have the proper ERR_PTR to retrun for different
kinds of errors.
Please let me know which option to continue with.
Thanks,
Danish
Thanks,
Mathieu
+
+ rproc = __pru_rproc_get(np, index);
+ if (IS_ERR(rproc))
+ return rproc;
+
+ pru = rproc->priv;
+ dev = &rproc->dev;
+
+ mutex_lock(&pru->lock);
+
+ if (pru->client_np) {
+ mutex_unlock(&pru->lock);
+ put_device(dev);
+ return ERR_PTR(-EBUSY);
+ }
+
+ pru->client_np = np;
+
+ mutex_unlock(&pru->lock);
+
+ if (pru_id)
+ *pru_id = pru->id;
+
+ return rproc;
+}
+EXPORT_SYMBOL_GPL(pru_rproc_get);
+
+/**
+ * pru_rproc_put() - release the PRU rproc resource
+ * @rproc: the rproc resource to release
+ *
+ * Releases the PRU rproc resource and makes it available to other
+ * users.
+ */
+void pru_rproc_put(struct rproc *rproc)
+{
+ struct pru_rproc *pru;
+
+ if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
+ return;
+
+ pru = rproc->priv;
+
+ mutex_lock(&pru->lock);
+
+ if (!pru->client_np) {
+ mutex_unlock(&pru->lock);
+ return;
+ }
+
+ pru->client_np = NULL;
+ mutex_unlock(&pru->lock);
+
+ put_device(&rproc->dev);
+}
+EXPORT_SYMBOL_GPL(pru_rproc_put);
+
static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
{
return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
@@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
/* PRU1 has its local RAM addresses reversed */
- if (pru->id == 1)
+ if (pru->id == PRUSS_PRU1)
swap(dram0, dram1);
shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
@@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
case RTU0_IRAM_ADDR_MASK:
fallthrough;
case PRU0_IRAM_ADDR_MASK:
- pru->id = 0;
+ pru->id = PRUSS_PRU0;
break;
case TX_PRU1_IRAM_ADDR_MASK:
fallthrough;
case RTU1_IRAM_ADDR_MASK:
fallthrough;
case PRU1_IRAM_ADDR_MASK:
- pru->id = 1;
+ pru->id = PRUSS_PRU1;
break;
default:
ret = -EINVAL;
@@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
pru->pruss = platform_get_drvdata(ppdev);
pru->rproc = rproc;
pru->fw_name = fw_name;
+ pru->client_np = NULL;
+ mutex_init(&pru->lock);
for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
@@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
static struct platform_driver pru_rproc_driver = {
.driver = {
- .name = "pru-rproc",
+ .name = PRU_RPROC_DRVNAME,
.of_match_table = pru_rproc_match,
.suppress_bind_attrs = true,
},
@@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
MODULE_AUTHOR("Suman Anna <s-anna@xxxxxx>");
MODULE_AUTHOR("Andrew F. Davis <afd@xxxxxx>");
MODULE_AUTHOR("Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx>");
+MODULE_AUTHOR("Puranjay Mohan <p-mohan@xxxxxx>");
MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
MODULE_LICENSE("GPL v2");
diff --git a/include/linux/pruss.h b/include/linux/pruss.h
new file mode 100644
index 000000000000..fdc719b43db0
--- /dev/null
+++ b/include/linux/pruss.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/**
+ * PRU-ICSS Subsystem user interfaces
+ *
+ * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
+ * Suman Anna <s-anna@xxxxxx>
+ */
+
+#ifndef __LINUX_PRUSS_H
+#define __LINUX_PRUSS_H
+
+#include <linux/device.h>
+#include <linux/types.h>
+
+#define PRU_RPROC_DRVNAME "pru-rproc"
+
+/*
+ * enum pruss_pru_id - PRU core identifiers
+ */
+enum pruss_pru_id {
+ PRUSS_PRU0 = 0,
+ PRUSS_PRU1,
+ PRUSS_NUM_PRUS,
+};
+
+struct device_node;
+
+#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
+
+struct rproc *pru_rproc_get(struct device_node *np, int index,
+ enum pruss_pru_id *pru_id);
+void pru_rproc_put(struct rproc *rproc);
+
+#else
+
+static inline struct rproc *
+pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void pru_rproc_put(struct rproc *rproc) { }
+
+#endif /* CONFIG_PRU_REMOTEPROC */
+
+static inline bool is_pru_rproc(struct device *dev)
+{
+ const char *drv_name = dev_driver_string(dev);
+
+ if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
+ return false;
+
+ return true;
+}
+
+#endif /* __LINUX_PRUSS_H */
--
2.17.1