[U-Boot] [PATCH v7 06/10] usb: host: ehci-generic: add error path and .remove callback

[Lothar Waßmann]

Hi,

On Tue, 20 Jun 2017 11:59:07 +0200 patrice.chotard at st.com wrote:
> From: Patrice Chotard <patrice.chotard at st.com>
> 
> Use an array to save enabled clocks reference and deasserted resets
> in order to respectively disabled and asserted them in case of error
> during probe() or during driver removal.
> 
> Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
> ---
> 
> v7:	_ replace clk_count() and reset_count() by ofnode_count_phandle_with_args()
> 
> v6:	_ none
> 
> v5: 	_ none
> 
> v4:	_ update the memory allocation for deasserted resets and enabled
> 	  clocks reference list. Replace lists by arrays.
> 	_ usage of new RESET and CLOCK methods clk_count(), reset_count(),
> 	  reset_assert_all() and clk_disable_all().
> 
> v3:	_ keep enabled clocks and deasserted resets reference in list in order to
> 	  disable clock or assert resets in error path or in .remove callback
> 	_ use struct generic_ehci * instead of struct udevice * as parameter for
> 	  ehci_release_resets() and ehci_release_clocks()
> 
>  drivers/usb/host/ehci-generic.c | 125 ++++++++++++++++++++++++++++++++--------
>  1 file changed, 101 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-generic.c b/drivers/usb/host/ehci-generic.c
> index 2116ae1..388b242 100644
> --- a/drivers/usb/host/ehci-generic.c
> +++ b/drivers/usb/host/ehci-generic.c
> @@ -11,6 +11,8 @@
>  #include <dm.h>
>  #include "ehci.h"
>  
> +#include <dm/ofnode.h>
> +
>  /*
>   * Even though here we don't explicitly use "struct ehci_ctrl"
>   * ehci_register() expects it to be the first thing that resides in
> @@ -18,43 +20,119 @@
>   */
>  struct generic_ehci {
>  	struct ehci_ctrl ctrl;
> +	struct clk *clocks;
> +	struct reset_ctl *resets;
> +	int clock_count;
> +	int reset_count;
>  };
>  
>  static int ehci_usb_probe(struct udevice *dev)
>  {
> +	struct generic_ehci *priv = dev_get_priv(dev);
>  	struct ehci_hccr *hccr;
>  	struct ehci_hcor *hcor;
> -	int i;
> -
> -	for (i = 0; ; i++) {
> -		struct clk clk;
> -		int ret;
> -
> -		ret = clk_get_by_index(dev, i, &clk);
> -		if (ret < 0)
> -			break;
> -		if (clk_enable(&clk))
> -			error("failed to enable clock %d\n", i);
> -		clk_free(&clk);
> -	}
> +	int i, err, ret, clock_nb, reset_nb;
> +
> +	err = 0;
> +	priv->clock_count = 0;
> +	clock_nb = ofnode_count_phandle_with_args(dev_ofnode(dev), "clocks",
> +						  "#clock-cells");
> +	if (clock_nb > 0) {
> +		priv->clocks = devm_kmalloc(dev, sizeof(struct clk) * clock_nb,
> +					    GFP_KERNEL);
> +		if (!priv->clocks) {
> +			error("Can't allocate resource\n");
> +			return -ENOMEM;
> +		}
> +
> +		for (i = 0; i < clock_nb; i++) {
> +			err = clk_get_by_index(dev, i, &priv->clocks[i]);
> +
> +			if (err < 0)
> +				break;
>  
> -	for (i = 0; ; i++) {
> -		struct reset_ctl reset;
> -		int ret;
> +			priv->clock_count++;
>  
> -		ret = reset_get_by_index(dev, i, &reset);
> -		if (ret < 0)
> -			break;
> -		if (reset_deassert(&reset))
> -			error("failed to deassert reset %d\n", i);
> -		reset_free(&reset);
> +			if (clk_enable(&priv->clocks[i])) {
> +				error("failed to enable clock %d\n", i);
> +				clk_free(&priv->clocks[i]);
>
You free the clock here and again with clk_disable_all() in the error
path. Also you do not have a valid error code in 'err' which is
returned at the end of the function!

> +				goto clk_err;
> +			}
> +			clk_free(&priv->clocks[i]);
> +		}
> +	} else {
> +		if (clock_nb != -ENOENT) {
> +			error("failed to get clock phandle(%d)\n", clock_nb);
> +			return clock_nb;
> +		}
>  	}
>  
> +	priv->reset_count = 0;
> +	reset_nb = ofnode_count_phandle_with_args(dev_ofnode(dev), "resets",
> +						  "#reset-cells");
> +	if (reset_nb > 0) {
> +		priv->resets = devm_kmalloc(dev,
> +					    sizeof(struct reset_ctl) * reset_nb,
> +					    GFP_KERNEL);
> +		if (!priv->resets) {
> +			error("Can't allocate resource\n");
> +			return -ENOMEM;
> +		}
> +
> +		for (i = 0; i < reset_nb; i++) {
> +			err = reset_get_by_index(dev, i, &priv->resets[i]);
> +			if (err < 0)
> +				break;
> +
> +			priv->reset_count++;
> +
> +			if (reset_deassert(&priv->resets[i])) {
> +				error("failed to deassert reset %d\n", i);
> +				reset_free(&priv->resets[i]);
> +				goto reset_err;
> +			}
> +			reset_free(&priv->resets[i]);
> +		}
> +	} else {
> +		if (reset_nb != -ENOENT) {
> +			error("failed to get reset phandle(%d)\n", reset_nb);
> +			goto clk_err;
> +		}
> +	}
>  	hccr = map_physmem(devfdt_get_addr(dev), 0x100, MAP_NOCACHE);
>  	hcor = (struct ehci_hcor *)((uintptr_t)hccr +
>  				    HC_LENGTH(ehci_readl(&hccr->cr_capbase)));
>  
> -	return ehci_register(dev, hccr, hcor, NULL, 0, USB_INIT_HOST);
> +	err = ehci_register(dev, hccr, hcor, NULL, 0, USB_INIT_HOST);
> +	if (!err)
> +		return err;
> +
> +reset_err:
> +	ret = reset_assert_all(priv->resets, priv->reset_count);
> +	if (ret)
> +		return ret;
>
You should do the clock cleanup even though the reset cleanup failed.

> +clk_err:
> +	ret = clk_disable_all(priv->clocks, priv->clock_count);
> +	if (ret)
> +		return ret;
>
You should return the error code of the operation that failed
initially (err), not some error code that has occured during cleanup.

> +	return err;
> +}
> +
> +static int ehci_usb_remove(struct udevice *dev)
> +{
> +	struct generic_ehci *priv = dev_get_priv(dev);
> +	int ret;
> +
> +	ret = ehci_deregister(dev);
> +	if (ret)
> +		return ret;
> +
> +	ret =  reset_assert_all(priv->resets, priv->reset_count);
> +	if (ret)
> +		return ret;
> +
> +	return clk_disable_all(priv->clocks, priv->clock_count);
>  }
>  
>  static const struct udevice_id ehci_usb_ids[] = {
> @@ -67,7 +145,7 @@ U_BOOT_DRIVER(ehci_generic) = {
>  	.id	= UCLASS_USB,
>  	.of_match = ehci_usb_ids,
>  	.probe = ehci_usb_probe,
> -	.remove = ehci_deregister,
> +	.remove = ehci_usb_remove,
>  	.ops	= &ehci_usb_ops,
>  	.priv_auto_alloc_size = sizeof(struct generic_ehci),
>  	.flags	= DM_FLAG_ALLOC_PRIV_DMA,


Lothar Waßmann