Hi Roger, On 12/12/22 14:47, Roger Quadros wrote: > Danish, > > On 09/12/2022 06:55, Md Danish Anwar wrote: >> Hi Roger, >> >> On 08/12/22 16:05, Roger Quadros wrote: >>> Hi, >>> >>> On 07/12/2022 13:04, MD Danish Anwar wrote: >>>> 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(). >>>> >>>> Signed-off-by: Suman Anna <s-anna@xxxxxx> >>>> Signed-off-by: Tero Kristo <t-kristo@xxxxxx> >>>> Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx> >>>> Signed-off-by: MD Danish Anwar <danishanwar@xxxxxx> >>>> --- >>>> drivers/remoteproc/pru_rproc.c | 133 ++++++++++++++++++++++++++++++++- >>>> include/linux/pruss.h | 29 +++++++ >>>> 2 files changed, 160 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c >>>> index a1a208b31846..7d4ed39b3772 100644 >>>> --- a/drivers/remoteproc/pru_rproc.c >>>> +++ b/drivers/remoteproc/pru_rproc.c >>>> @@ -2,12 +2,14 @@ >>>> /* >>>> * 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> >>>> + * Md Danish Anwar <danishanwar@xxxxxx> >>>> */ >>>> >>>> #include <linux/bitops.h> >>>> @@ -112,6 +114,8 @@ 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) >>>> @@ -127,6 +131,8 @@ 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; >>>> const char *fw_name; >>>> unsigned int *mapped_irq; >>>> struct pru_irq_rsc *pru_interrupt_map; >>>> @@ -147,6 +153,125 @@ 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 rproc *rproc; >>>> + phandle rproc_phandle; >>>> + int ret; >>>> + >>>> + ret = of_property_read_u32_index(np, "ti,prus", index, &rproc_phandle); >>>> + if (ret) >>>> + return ERR_PTR(ret); >>>> + >>>> + rproc = rproc_get_by_phandle(rproc_phandle); >>>> + if (!rproc) { >>>> + ret = -EPROBE_DEFER; >>>> + goto err_no_rproc_handle; >>>> + } >>>> + >>>> + /* make sure it is PRU rproc */ >>>> + if (!is_pru_rproc(rproc->dev.parent)) { >>>> + rproc_put(rproc); >>>> + return ERR_PTR(-ENODEV); >>>> + } >>>> + >>>> + return rproc; >>>> + >>>> +err_no_rproc_handle: >>>> + rproc_put(rproc); >>>> + return ERR_PTR(ret); >>>> +} >>>> + >>>> +/** >>>> + * 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; >>>> + int ret; >>>> + >>>> + 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); >>> >>> Is this put_device() to counter balance the get_device() you had earlier? >>> Is it still needed? >>>> Did we do the right thing by getting rid of the additional get_device()? >>> I didn't see a reason for it. >>> >> >> The previous get_device() in __pru_rproc_get() was additional/not required as >> the same get_device() was called by rproc_get_by_phandle() API before it's >> completion. >> >> So that get_device() is not needed. >> >> The put_device() here is to counter the get_device() called by >> rproc_get_by_phandle() in the API __pru_rproc_get(). >> >> So I think, this put_device() is still needed. > > But at the end of this function we are calling rproc_put() > which also does a put_device(), right? > Yes, from here we are going to the label err_no_rproc_handle where rproc_put() API is called. Which is further calling put_device(). So essentially we are doing two put device instead of one. So I think, I should remove the put_device() from the below if block if (pru->client_np) { mutex_unlock(&pru->lock); put_device(dev); ret = -EBUSY; goto err_no_rproc_handle; } >> >>>> + ret = -EBUSY; >>>> + goto err_no_rproc_handle; >>>> + } >>>> + >>>> + pru->client_np = np; >>>> + >>>> + mutex_unlock(&pru->lock); >>>> + >>>> + if (pru_id) >>>> + *pru_id = pru->id; >>>> + >>>> + return rproc; >>>> + >>>> +err_no_rproc_handle: >>>> + rproc_put(rproc); >>>> + return ERR_PTR(ret); >>>> +} >>>> +EXPORT_SYMBOL_GPL(pru_rproc_get); > > <snip> > > cheers, > -roger
