[U-Boot] [PATCH v3 5/7] usb: host: ohci-generic: add CLOCK support

[Patrice CHOTARD]

On 05/19/2017 01:51 PM, Marek Vasut wrote:
> On 05/19/2017 01:27 PM, Patrice CHOTARD wrote:
>> Hi Marek
>>
>> On 05/18/2017 11:29 AM, Marek Vasut wrote:
>>> On 05/17/2017 03:34 PM, patrice.chotard at st.com wrote:
>>>> From: Patrice Chotard <patrice.chotard at st.com>
>>>>
>>>> use list to save reference to enabled clocks in order to
>>>> disabled them in case of error during probe() or
>>>> during driver removal.
>>>>
>>>> Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
>>>> ---
>>>>
>>>> v3:	_ extract in this patch the CLOCK support add-on from previous patch 5
>>>> 	_ keep enabled clocks reference in list in order to
>>>> 	  disable clocks in error path or in .remove callback
>>>>
>>>> v2:	_ add error path management
>>>> 	_ add .remove callback
>>>>
>>>>    drivers/usb/host/ohci-generic.c | 81 ++++++++++++++++++++++++++++++++++++++++-
>>>>    1 file changed, 80 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/usb/host/ohci-generic.c b/drivers/usb/host/ohci-generic.c
>>>> index f3307f4..a6d89a8 100644
>>>> --- a/drivers/usb/host/ohci-generic.c
>>>> +++ b/drivers/usb/host/ohci-generic.c
>>>> @@ -5,6 +5,7 @@
>>>>     */
>>>>    
>>>>    #include <common.h>
>>>> +#include <clk.h>
>>>>    #include <dm.h>
>>>>    #include "ohci.h"
>>>>    
>>>> @@ -12,20 +13,98 @@
>>>>    # error "Generic OHCI driver requires CONFIG_USB_OHCI_NEW"
>>>>    #endif
>>>>    
>>>> +struct ohci_clock {
>>>> +	struct clk *clk;
>>>> +	struct list_head list;
>>>> +};
>>>> +
>>>>    struct generic_ohci {
>>>>    	ohci_t ohci;
>>>> +	struct list_head clks;
>>>>    };
>>>>    
>>>> +static int ohci_release_clocks(struct generic_ohci *priv)
>>>> +{
>>>> +	struct ohci_clock *ohci_clock, *tmp;
>>>> +	struct clk *clk;
>>>> +	int ret;
>>>> +
>>>> +	list_for_each_entry_safe(ohci_clock, tmp, &priv->clks, list) {
>>>> +		clk = ohci_clock->clk;
>>>> +
>>>> +		clk_request(clk->dev, clk);
>>>> +		if (ret)
>>>> +			return ret;
>>>> +
>>>> +		clk_disable(clk);
>>>> +
>>>> +		ret = clk_free(clk);
>>>> +		if (ret)
>>>> +			return ret;
>>>> +
>>>> +		list_del(&ohci_clock->list);
>>>> +	}
>>>> +	return 0;
>>>> +}
>>>> +
>>>>    static int ohci_usb_probe(struct udevice *dev)
>>>>    {
>>>>    	struct ohci_regs *regs = (struct ohci_regs *)dev_get_addr(dev);
>>>> +	struct generic_ohci *priv = dev_get_priv(dev);
>>>> +	int i, ret;
>>>> +
>>>> +	INIT_LIST_HEAD(&priv->clks);
>>>> +
>>>> +	for (i = 0; ; i++) {
>>>> +		struct ohci_clock *ohci_clock;
>>>> +		struct clk *clk;
>>>> +
>>>> +		clk = devm_kmalloc(dev, sizeof(*clk), GFP_KERNEL);
>>>
>>> Since you know how many entries the clock phandle has, you can allocate
>>> an array and drop this while list handling and this per-element kmalloc,
>>> which fragments the allocator pool.
>>
>> I disagree, at this point we don't know how many entries the clock
>> phandle has.
> 
> I know you can do it in less then 2 mallocs,  in fact in exactly 1 ,
> which is already better.

Can you elaborate ?

> 
>> But, following your idea to avoid allocator pool fragmentation, in order
>> to get the phandle number for array allocation, i can, for example add a
>> new fdt API :
>>
>> int fdtdec_get_phandle_nb(const void *blob, int src_node,
>> 				   const char *list_name,
>> 				   const char *cells_name,
>> 				   int cell_count,
>> 				   int phandle_nb);
> 
> Uh, why ?
> 
>> Then, with phandle_nb,, we 'll be able to allocate the right array size
>> for clocks and resets before populating them.
> 
> Just query the number of elements up front and then allocate the array ?

Can you indicate me with which API please ?

> 
>> Thanks
>>
>> Patrice
>>
>>>
>>>> +		if (!clk) {
>>>> +			error("Can't allocate resource\n");
>>>> +			goto clk_err;
>>>> +		}
>>>> +
>>>> +		ret = clk_get_by_index(dev, i, clk);
>>>> +		if (ret < 0)
>>>> +			break;
>>>> +
>>>> +		if (clk_enable(clk)) {
>>>> +			error("failed to enable ohci_clock %d\n", i);
>>>> +			clk_free(clk);
>>>> +			goto clk_err;
>>>> +		}
>>>> +		clk_free(clk);
>>>> +
>>>> +		/*
>>>> +		 * add enabled clocks into clks list in order to be disabled
>>>> +		 * later on ohci_usb_remove() call or in error path if needed
>>>> +		 */
>>>> +		ohci_clock = devm_kmalloc(dev, sizeof(*ohci_clock), GFP_KERNEL);
>>>
>>> Can't you just embed one structure into the other ?
>>>
>>>> +		if (!ohci_clock) {
>>>> +			error("Can't allocate resource\n");
>>>> +			goto clk_err;
>>>> +		}
>>>> +		ohci_clock->clk = clk;
>>>> +		list_add(&ohci_clock->list, &priv->clks);
>>>> +	}
>>>>    
>>>>    	return ohci_register(dev, regs);
>>>> +
>>>> +clk_err:
>>>> +	return ohci_release_clocks(priv);
>>>>    }
>>>>    
>>>>    static int ohci_usb_remove(struct udevice *dev)
>>>>    {
>>>> -	return ohci_deregister(dev);
>>>> +	struct generic_ohci *priv = dev_get_priv(dev);
>>>> +	int ret;
>>>> +
>>>> +	ret = ohci_deregister(dev);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	return ohci_release_clocks(priv);
>>>>    }
>>>>    
>>>>    static const struct udevice_id ohci_usb_ids[] = {
>>>>
>>>
> 
>