Re: [PATCH] dmaengine: bestcomm: ioremap and get irq early

On Sun, Aug 16, 2026 at 05:45:00PM -0700, Rosen Penev wrote:
> Doing so allows handling potential -EPROBE_DEFER before any work gets
> done.
>
> 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
> now-unused error-unmap/release paths and simplifies the driver.
>
> Assisted-by: opencode:hy3-free
> Signed-off-by: Rosen Penev <[email protected]>
>
> dmaengine: bestcomm: get irq early

make irq change as seperate patch

Reviewed-by: Frank Li <[email protected]>

>
> platform_get_irq can return -EPROBE_DEFER, which is useful to avoid
> doing extra work in such a case
>
> Signed-off-by: Rosen Penev <[email protected]>
> ---
>  drivers/dma/bestcomm/bestcomm.c            | 70 ++++++----------------
>  include/linux/fsl/bestcomm/bestcomm_priv.h |  2 +-
>  2 files changed, 18 insertions(+), 54 deletions(-)
>
> diff --git a/drivers/dma/bestcomm/bestcomm.c b/drivers/dma/bestcomm/bestcomm.c
> index 432b43520ddc..55ad7bc34df7 100644
> --- a/drivers/dma/bestcomm/bestcomm.c
> +++ b/drivers/dma/bestcomm/bestcomm.c
> @@ -48,6 +48,7 @@ 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)
> @@ -68,6 +69,10 @@ 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)
> +		return irq;
> +
>  	/* Allocate our structure */
>  	tsk = kzalloc(sizeof(struct bcom_task) + priv_size, GFP_KERNEL);
>  	if (!tsk)
> @@ -77,10 +82,7 @@ bcom_task_alloc(int bd_count, int bd_size, int priv_size)
>  	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) {
> @@ -102,8 +104,6 @@ bcom_task_alloc(int bd_count, int bd_size, int priv_size)
>
>  error:
>  	if (tsk) {
> -		if (tsk->irq)
> -			irq_dispose_mapping(tsk->irq);
>  		bcom_sram_free(tsk->bd);
>  		kfree(tsk->cookie);
>  		kfree(tsk);
> @@ -126,7 +126,6 @@ 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);
> @@ -365,23 +364,24 @@ bcom_engine_cleanup(void)
>  static int mpc52xx_bcom_probe(struct platform_device *op)
>  {
>  	struct device_node *ofn_sram;
> -	struct resource res_bcom;
> +	struct resource *res_bcom;
> +	void __iomem *regs;
>
>  	int rv;
>
>  	/* Inform user we're ok so far */
>  	printk(KERN_INFO "DMA: MPC52xx BestComm driver\n");
>
> -	/* Get the bestcomm node */
> -	of_node_get(op->dev.of_node);
> +	regs = devm_platform_get_and_ioremap_resource(op, 0, &res_bcom);
> +	if (IS_ERR(regs))
> +		return PTR_ERR(regs);
>
>  	/* 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);
> @@ -389,7 +389,7 @@ 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 */
> @@ -400,37 +400,14 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
>  	}
>
>  	/* Save the node */
> -	bcom_eng->ofnode = op->dev.of_node;
> -
> -	/* Get, reserve & map io */
> -	if (of_address_to_resource(op->dev.of_node, 0, &res_bcom)) {
> -		printk(KERN_ERR DRIVER_NAME ": "
> -			"Can't get resource\n");
> -		rv = -EINVAL;
> -		goto error_sramclean;
> -	}
> -
> -	if (!request_mem_region(res_bcom.start, resource_size(&res_bcom),
> -				DRIVER_NAME)) {
> -		printk(KERN_ERR DRIVER_NAME ": "
> -			"Can't request registers region\n");
> -		rv = -EBUSY;
> -		goto error_sramclean;
> -	}
> -
> -	bcom_eng->regs_base = res_bcom.start;
> -	bcom_eng->regs = ioremap(res_bcom.start, sizeof(struct mpc52xx_sdma));
> -	if (!bcom_eng->regs) {
> -		printk(KERN_ERR DRIVER_NAME ": "
> -			"Can't map registers\n");
> -		rv = -ENOMEM;
> -		goto error_release;
> -	}
> +	bcom_eng->pdev = op;
> +	bcom_eng->regs = regs;
> +	bcom_eng->regs_base = res_bcom->start;
>
>  	/* Now, do the real init */
>  	rv = bcom_engine_init();
>  	if (rv)
> -		goto error_unmap;
> +		goto error_sramclean;
>
>  	/* Done ! */
>  	printk(KERN_INFO "DMA: MPC52xx BestComm engine @%08lx ok !\n",
> @@ -439,15 +416,9 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
>  	return 0;
>
>  	/* Error path */
> -error_unmap:
> -	iounmap(bcom_eng->regs);
> -error_release:
> -	release_mem_region(res_bcom.start, sizeof(struct mpc52xx_sdma));
>  error_sramclean:
>  	kfree(bcom_eng);
>  	bcom_sram_cleanup();
> -error_ofput:
> -	of_node_put(op->dev.of_node);
>
>  	printk(KERN_ERR "DMA: MPC52xx BestComm init failed !\n");
>
> @@ -463,13 +434,6 @@ static void mpc52xx_bcom_remove(struct platform_device *op)
>  	/* Cleanup SRAM */
>  	bcom_sram_cleanup();
>
> -	/* Release regs */
> -	iounmap(bcom_eng->regs);
> -	release_mem_region(bcom_eng->regs_base, sizeof(struct mpc52xx_sdma));
> -
> -	/* 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
>