Re: [PATCHv2] dmaengine: bestcomm: use platform machinery to get irq

[Frank Li <Frank.li@oss.nxp.com>]

On Wed, Sep 16, 2026 at 03:41:56PM -0700, Rosen Penev wrote:
> platform_get_irq() avoids having to explicitly map and dispose of an irq
> by having the platform_device machinery take care of it.
>
> This requires replacing the device_node with a platform_device in the
> bcom_eng struct so that platform_get_irq() can use it.
>
> Conveniently, this also allows getting rid of of_node_get and
> of_node_put as the platform_device machinery also handles that.
>
> Replace the open-coded resource lookup, request_mem_region, ioremap and
> the manual iounmap/release_mem_region cleanup in probe/remove with the
> managed devm_platform_get_and_ioremap_resource() helper. This removes the

update commit message, no devm_platform_get_and_ioremap_resource() in patch.

> now-unused error-unmap/release paths and simplifies the driver.
>
> Adjust the goto labels in bcom_task_alloc to match what is being freed.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>  v2: resend.

If resend, don't pump version.

Frank
>  drivers/dma/bestcomm/bestcomm.c            | 47 ++++++++--------------
>  include/linux/fsl/bestcomm/bestcomm_priv.h |  2 +-
>  2 files changed, 18 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/dma/bestcomm/bestcomm.c b/drivers/dma/bestcomm/bestcomm.c
> index 241a91936fe8..1006030ff167 100644
> --- a/drivers/dma/bestcomm/bestcomm.c
> +++ b/drivers/dma/bestcomm/bestcomm.c
> @@ -47,6 +47,7 @@ bcom_task_alloc(int bd_count, int bd_size, int priv_size)
>  {
>  	int i, tasknum = -1;
>  	struct bcom_task *tsk;
> +	int irq;
>
>  	/* Don't try to do anything if bestcomm init failed */
>  	if (!bcom_eng)
> @@ -67,30 +68,32 @@ bcom_task_alloc(int bd_count, int bd_size, int priv_size)
>  	if (tasknum < 0)
>  		return NULL;
>
> +	irq = platform_get_irq(bcom_eng->pdev, tasknum);
> +	if (irq < 0)
> +		goto err1;
> +
>  	/* Allocate our structure */
>  	tsk = kzalloc(sizeof(struct bcom_task) + priv_size, GFP_KERNEL);
>  	if (!tsk)
> -		goto error;
> +		goto err1;
>
>  	tsk->tasknum = tasknum;
>  	if (priv_size)
>  		tsk->priv = (void*)tsk + sizeof(struct bcom_task);
>
>  	/* Get IRQ of that task */
> -	tsk->irq = irq_of_parse_and_map(bcom_eng->ofnode, tsk->tasknum);
> -	if (!tsk->irq)
> -		goto error;
> +	tsk->irq = irq;
>
>  	/* Init the BDs, if needed */
>  	if (bd_count) {
>  		tsk->cookie = kmalloc_array(bd_count, sizeof(void *),
>  					    GFP_KERNEL);
>  		if (!tsk->cookie)
> -			goto error;
> +			goto err2;
>
>  		tsk->bd = bcom_sram_alloc(bd_count * bd_size, 4, &tsk->bd_pa);
>  		if (!tsk->bd)
> -			goto error;
> +			goto err3;
>  		memset_io(tsk->bd, 0x00, bd_count * bd_size);
>
>  		tsk->num_bd = bd_count;
> @@ -99,17 +102,12 @@ bcom_task_alloc(int bd_count, int bd_size, int priv_size)
>
>  	return tsk;
>
> -error:
> -	if (tsk) {
> -		if (tsk->irq)
> -			irq_dispose_mapping(tsk->irq);
> -		bcom_sram_free(tsk->bd);
> -		kfree(tsk->cookie);
> -		kfree(tsk);
> -	}
> -
> +err3:
> +	kfree(tsk->cookie);
> +err2:
> +	kfree(tsk);
> +err1:
>  	bcom_eng->tdt[tasknum].stop = 0;
> -

avoid unnecesary change.

>  	return NULL;
>  }
>  EXPORT_SYMBOL_GPL(bcom_task_alloc);
> @@ -125,7 +123,6 @@ bcom_task_free(struct bcom_task *tsk)
>  	bcom_eng->tdt[tsk->tasknum].stop  = 0;
>
>  	/* Free everything */
> -	irq_dispose_mapping(tsk->irq);
>  	bcom_sram_free(tsk->bd);
>  	kfree(tsk->cookie);
>  	kfree(tsk);
> @@ -377,16 +374,12 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
>  	if (IS_ERR(regs))
>  		return PTR_ERR(regs);
>
> -	/* Get the bestcomm node */
> -	of_node_get(op->dev.of_node);
> -
>  	/* Prepare SRAM */
>  	ofn_sram = of_find_matching_node(NULL, mpc52xx_sram_ids);
>  	if (!ofn_sram) {
>  		printk(KERN_ERR DRIVER_NAME ": "
>  			"No SRAM found in device tree\n");
> -		rv = -ENODEV;
> -		goto error_ofput;
> +		return -ENODEV;
>  	}
>  	rv = bcom_sram_init(ofn_sram, DRIVER_NAME);
>  	of_node_put(ofn_sram);
> @@ -394,7 +387,7 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
>  	if (rv) {
>  		printk(KERN_ERR DRIVER_NAME ": "
>  			"Error in SRAM init\n");
> -		goto error_ofput;
> +		return rv;
>  	}
>
>  	/* Get a clean struct */
> @@ -405,8 +398,7 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
>  	}
>
>  	/* Save the node */
> -	bcom_eng->ofnode = op->dev.of_node;
> -
> +	bcom_eng->pdev = op;
>  	bcom_eng->regs = regs;
>  	bcom_eng->regs_base = res_bcom->start;
>
> @@ -426,8 +418,6 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
>  	kfree(bcom_eng);
>  	bcom_eng = NULL;
>  	bcom_sram_cleanup();
> -error_ofput:
> -	of_node_put(op->dev.of_node);
>
>  	printk(KERN_ERR "DMA: MPC52xx BestComm init failed !\n");
>
> @@ -443,9 +433,6 @@ static void mpc52xx_bcom_remove(struct platform_device *op)
>  	/* Cleanup SRAM */
>  	bcom_sram_cleanup();
>
> -	/* Release the node */
> -	of_node_put(bcom_eng->ofnode);
> -
>  	/* Release memory */
>  	kfree(bcom_eng);
>  	bcom_eng = NULL;
> diff --git a/include/linux/fsl/bestcomm/bestcomm_priv.h b/include/linux/fsl/bestcomm/bestcomm_priv.h
> index 3b52f3ffbdf8..cddde7c74cb5 100644
> --- a/include/linux/fsl/bestcomm/bestcomm_priv.h
> +++ b/include/linux/fsl/bestcomm/bestcomm_priv.h
> @@ -66,7 +66,7 @@ struct bcom_tdt {
>   * This holds all info needed globaly to handle the engine
>   */
>  struct bcom_engine {
> -	struct device_node		*ofnode;
> +	struct platform_device		*pdev;
>  	struct mpc52xx_sdma __iomem     *regs;
>  	phys_addr_t                      regs_base;
>
> --
> 2.55.0
>