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    Subject[PATCH 2/5] remoteproc: pru: Add APIs to get and put the PRU cores
    Date
    From: Tero Kristo <t-kristo@ti.com>

    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 "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@ti.com>
    Signed-off-by: Suman Anna <s-anna@ti.com>
    Signed-off-by: Tero Kristo <t-kristo@ti.com>
    Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
    Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
    ---
    drivers/remoteproc/pru_rproc.c | 125 ++++++++++++++++++++++++++++++++-
    include/linux/pruss.h | 56 +++++++++++++++
    2 files changed, 178 insertions(+), 3 deletions(-)
    create mode 100644 include/linux/pruss.h

    diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
    index 2667919d76b3..cc2e585778b1 100644
    --- a/drivers/remoteproc/pru_rproc.c
    +++ b/drivers/remoteproc/pru_rproc.c
    @@ -16,6 +16,7 @@
    #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 +112,8 @@ 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 +129,8 @@ 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 +151,119 @@ 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, "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)
    + /* 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 prus property
    + * @pru_id: optional pointer to return the PRU remoteproc processor id
    + *
    + * This function looks through a client device node's "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;
    +
    + 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;
    + if (!pru->client_np)
    + return;
    +
    + mutex_lock(&pru->lock);
    + 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);
    @@ -706,14 +824,14 @@ 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;
    @@ -775,6 +893,7 @@ static int pru_rproc_probe(struct platform_device *pdev)
    pru->pruss = platform_get_drvdata(ppdev);
    pru->rproc = rproc;
    pru->fw_name = fw_name;
    + mutex_init(&pru->lock);

    for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
    res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
    @@ -859,7 +978,7 @@ 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,
    },
    diff --git a/include/linux/pruss.h b/include/linux/pruss.h
    new file mode 100644
    index 000000000000..43cb5c2eed08
    --- /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) 2015-2020 Texas Instruments Incorporated - http://www.ti.com
    + * Suman Anna <s-anna@ti.com>
    + */
    +
    +#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(-ENOTSUPP);
    +}
    +
    +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 */
    --
    2.29.0
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