Re: [PATCH v12 5/6] remoteproc: pru: Add pru_rproc_set_ctable() function

[Roger Quadros]

Hi Danish,

On 23/12/2022 12:58, Md Danish Anwar wrote:
> Hi Roger,
> 
> Can you please review this patch.

I am the author of that patch so my review tag will be kind or worthless. ;)

cheers,
-roger

> 
> Thanks,
> Danish.
> 
> On 16/12/22 11:03, MD Danish Anwar wrote:
>> From: Roger Quadros <rogerq@xxxxxx>
>>
>> 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.
>>
>> CTABLE for stands for "constant table".
>> Each CTable entry just holds the upper address bits so PRU can
>> reference to external memory with larger address bits.
>>
>> For use case please see
>> prueth_sw_emac_config() in "drivers/net/ethernet/ti/prueth_switch.c"
>>
>>             /* Set in constant table C28 of PRUn to ICSS Shared memory */
>>              pru_rproc_set_ctable(prueth->pru0, PRU_C28, sharedramaddr);
>>              pru_rproc_set_ctable(prueth->pru1, PRU_C28, sharedramaddr);
>>
>>             /* Set in constant table C30 of PRUn to OCMC memory */
>>              pru_rproc_set_ctable(prueth->pru0, PRU_C30, ocmcaddr);
>>              pru_rproc_set_ctable(prueth->pru1, PRU_C30, ocmcaddr);
>>
>> Signed-off-by: Andrew F. Davis <afd@xxxxxx>
>> Signed-off-by: Suman Anna <s-anna@xxxxxx>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@xxxxxxxxxx>
>> Signed-off-by: MD Danish Anwar <danishanwar@xxxxxx>
>> ---
>>  drivers/remoteproc/pru_rproc.c | 59 ++++++++++++++++++++++++++++++++++
>>  include/linux/pruss.h          | 22 +++++++++++++
>>  2 files changed, 81 insertions(+)
>>
>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>> index 8e2fbe392ef3..176186882acf 100644
>> --- a/drivers/remoteproc/pru_rproc.c
>> +++ b/drivers/remoteproc/pru_rproc.c
>> @@ -120,6 +120,7 @@ struct pru_private_data {
>>   * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>>   * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
>>   * @pru_interrupt_map_sz: pru_interrupt_map size
>> + * @rmw_lock: lock for read, modify, write operations on registers
>>   * @dbg_single_step: debug state variable to set PRU into single step mode
>>   * @dbg_continuous: debug state variable to restore PRU execution mode
>>   * @evt_count: number of mapped events
>> @@ -137,6 +138,7 @@ struct pru_rproc {
>>  	unsigned int *mapped_irq;
>>  	struct pru_irq_rsc *pru_interrupt_map;
>>  	size_t pru_interrupt_map_sz;
>> +	spinlock_t rmw_lock;
>>  	u32 dbg_single_step;
>>  	u32 dbg_continuous;
>>  	u8 evt_count;
>> @@ -153,6 +155,23 @@ 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 inline
>> +void pru_control_set_reg(struct pru_rproc *pru, unsigned int reg,
>> +			 u32 mask, u32 set)
>> +{
>> +	u32 val;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&pru->rmw_lock, flags);
>> +
>> +	val = pru_control_read_reg(pru, reg);
>> +	val &= ~mask;
>> +	val |= (set & mask);
>> +	pru_control_write_reg(pru, reg, val);
>> +
>> +	spin_unlock_irqrestore(&pru->rmw_lock, flags);
>> +}
>> +
>>  static struct rproc *__pru_rproc_get(struct device_node *np, int index)
>>  {
>>  	struct rproc *rproc;
>> @@ -269,6 +288,45 @@ 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
>> + *
>> + * Return: 0 on success, or errno in error case.
>> + */
>> +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;
>> +
>> +	if (IS_ERR_OR_NULL(rproc))
>> +		return -EINVAL;
>> +
>> +	if (!rproc->dev.parent || !is_pru_rproc(rproc->dev.parent))
>> +		return -ENODEV;
>> +
>> +	/* 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));
>> +
>> +	pru_control_set_reg(pru, reg, mask, set);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(pru_rproc_set_ctable);
>> +
>>  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);
>> @@ -940,6 +998,7 @@ static int pru_rproc_probe(struct platform_device *pdev)
>>  	pru->rproc = rproc;
>>  	pru->fw_name = fw_name;
>>  	pru->client_np = NULL;
>> +	spin_lock_init(&pru->rmw_lock);
>>  	mutex_init(&pru->lock);
>>  
>>  	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
>> index 6ea737e995e9..a6bc3df92fee 100644
>> --- a/include/linux/pruss.h
>> +++ b/include/linux/pruss.h
>> @@ -28,13 +28,29 @@ enum pruss_pru_id {
>>  	PRUSS_NUM_PRUS,
>>  };
>>  
>> +/*
>> + * 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,
>> +};
>> +
>>  struct device_node;
>> +struct rproc;
>>  
>>  #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);
>> +int pru_rproc_set_ctable(struct rproc *rproc, enum pru_ctable_idx c, u32 addr);
>>  
>>  #else
>>  
>> @@ -46,6 +62,12 @@ pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
>>  
>>  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 -EOPNOTSUPP;
>> +}
>> +
>>  #endif /* CONFIG_PRU_REMOTEPROC */
>>  
>>  static inline bool is_pru_rproc(struct device *dev)