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

[Patrice CHOTARD]

Hi Lothar

On 06/20/2017 01:32 PM, Lothar Waßmann wrote:
> 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!

Good catch, to fix it, i will move the priv->clock_count++ after the 
clk_enable statement. In this case, in the error path, only clocks which 
have been previously correctly enabled will be requested/disabled/freed

Ok i will catch the error code in err and use it as return value.


> 
>> +				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.

Agree, i will fix it

> 
>> +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.

Agree again

Thanks

Patrice

> 
>> +	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
>