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Date: Fri, 2 Nov 2018 00:36:01 +0900
From: Jaewon Kim <jaewon02.kim@...il.com>
To: Frank Rowand <frowand.list@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Jaewon Kim <jaewon02.kim@...sung.com>
Cc: Jaewon Kim <jaewon02.kim@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] of/platform: Support dynamic device tree on AMBA bus
On 11/1/18 1:06 AM, Frank Rowand wrote:
> On 10/31/18 8:32 AM, Jaewon Kim wrote:
>> Hi Frank,
>>
>>
>> Thanks to review my patch.
>>
>> On 18. 10. 31. 오전 8:04, Frank Rowand wrote:
>>> Hi Jaewon,
>>>
>>> On 10/25/18 9:39 AM, Jaewon Kim wrote:
>>>> This patch supports dynamic device-tree for AMBA device.
>>> Add AMBA devices and buses to of_platform_notify() so that dynamic device-tree
>>> will support AMBA.
>> What is meaning of this comment?
>>
>> I already adds AMBA to of_platform_notify().
> I was trying to make the commit comment more explanatory. (And finding it difficult
> to remain brief, yet meaningful.) The original patch header comment did not tell me
> why the patch changes added support of dynamic devicetree on AMBA - I had to read the
> patch before I understood what it did. If you can think of better words than I
> suggested, please come up with different wording.
>
> My intent with this sentence was that more explanation needed to be added to the
> comment, not that the code needed to change in any way other than what I noted
> in-line inside the patch. Does this make things more clear, or am I misunderstanding
> your question?
>
> -Frank
Now I understand your intentions.
I will write more clear comment in the next patch version.
Thanks
Jaewon Kim
>
>
>>>> The AMBA device must be registered on the AMBA bus, not the platform bus.
>>>>
>>>> Signed-off-by: Jaewon Kim <jaewon02.kim@...sung.com>
>>>> ---
>>>> drivers/of/platform.c | 93 ++++++++++++++++++++++++++++++++++++++++-----------
>>>> 1 file changed, 73 insertions(+), 20 deletions(-)
>>>>
>>>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>>>> index 04ad312..b9ac105 100644
>>>> --- a/drivers/of/platform.c
>>>> +++ b/drivers/of/platform.c
>>>> @@ -286,6 +286,22 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
>>>> of_node_clear_flag(node, OF_POPULATED);
>>>> return NULL;
>>>> }
>>>> +
>>>> +/**
>>>> + * of_find_amba_device_by_node - Find the amba_device associated with a node
>>>> + * @np: Pointer to device tree node
>>>> + *
>>>> + * Returns amba_device pointer, or NULL if not found
>>>> + */
>>>> +struct amba_device *of_find_amba_device_by_node(struct device_node *np)
>>>> +{
>>>> + struct device *dev;
>>>> +
>>>> + dev = bus_find_device(&amba_bustype, NULL, np, of_dev_node_match);
>>>> + return dev ? to_amba_device(dev) : NULL;
>>>> +}
>>>> +EXPORT_SYMBOL(of_find_amba_device_by_node);
>>>> +
>>>> #else /* CONFIG_ARM_AMBA */
>>>> static struct amba_device *of_amba_device_create(struct device_node *node,
>>>> const char *bus_id,
>>>> @@ -294,6 +310,12 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
>>>> {
>>>> return NULL;
>>>> }
>>>> +
>>>> +struct amba_device *of_find_amba_device_by_node(struct device_node *np)
>>>> +{
>>>> + return NULL;
>>>> +}
>>>> +EXPORT_SYMBOL(of_find_amba_device_by_node);
>>>> #endif /* CONFIG_ARM_AMBA */
>>>> /**
>>>> @@ -665,6 +687,7 @@ static int of_platform_notify(struct notifier_block *nb,
>>>> {
>>>> struct of_reconfig_data *rd = arg;
>>>> struct platform_device *pdev_parent, *pdev;
>>>> + struct amba_device *adev_p, *adev;
>>>> bool children_left;
>>>> switch (of_reconfig_get_state_change(action, rd)) {
>>>> @@ -677,17 +700,34 @@ static int of_platform_notify(struct notifier_block *nb,
>>>> if (of_node_check_flag(rd->dn, OF_POPULATED))
>>>> return NOTIFY_OK;
>>>> - /* pdev_parent may be NULL when no bus platform device */
>>>> - pdev_parent = of_find_device_by_node(rd->dn->parent);
>>>> - pdev = of_platform_device_create(rd->dn, NULL,
>>>> - pdev_parent ? &pdev_parent->dev : NULL);
>>>> - of_dev_put(pdev_parent);
>>>> -
>>>> - if (pdev == NULL) {
>>>> - pr_err("%s: failed to create for '%pOF'\n",
>>>> - __func__, rd->dn);
>>>> - /* of_platform_device_create tosses the error code */
>>>> - return notifier_from_errno(-EINVAL);
>>>> + if (of_device_is_compatible(rd->dn, "arm,primecell")) {
>>>> + /* adev_p may be NULL when no bus amba device */
>>>> + adev_p = of_find_amba_device_by_node(rd->dn->parent);
>>>> + adev = of_amba_device_create(rd->dn, NULL, NULL,
>>>> + adev_p ? &adev_p->dev : NULL);
>>>> +
>>>> + if (adev_p)
>>>> + put_device(&adev_p->dev);
>>> Please follow the same model as of_dev_put() here, create a new function
>>> of_amba_dev_put() to implement these two lines.
>> Okay, I will create of_amba_dev_put() function.
>>>
>>>> +
>>>> + if (adev == NULL) {
>>>> + pr_err("%s: failed to create for '%s'\n",
>>>> + __func__, rd->dn->full_name);
>>>> + /* of_amba_device_create tosses the error */
>>>> + return notifier_from_errno(-EINVAL);
>>>> + }
>>>> + } else {
>>>> + /* pdev_parent may be NULL when no bus platform device*/
>>>> + pdev_parent = of_find_device_by_node(rd->dn->parent);
>>>> + pdev = of_platform_device_create(rd->dn, NULL,
>>>> + pdev_parent ? &pdev_parent->dev : NULL);
>>>> + of_dev_put(pdev_parent);
>>>> +
>>>> + if (pdev == NULL) {
>>>> + pr_err("%s: failed to create for '%pOF'\n",
>>>> + __func__, rd->dn);
>>>> + /* of_platform_device_create tosses the error */
>>>> + return notifier_from_errno(-EINVAL);
>>>> + }
>>>> }
>>>> break;
>>>> @@ -698,15 +738,28 @@ static int of_platform_notify(struct notifier_block *nb,
>>>> return NOTIFY_OK;
>>>> /* find our device by node */
>>>> - pdev = of_find_device_by_node(rd->dn);
>>>> - if (pdev == NULL)
>>>> - return NOTIFY_OK; /* no? not meant for us */
>>>> -
>>>> - /* unregister takes one ref away */
>>>> - of_platform_device_destroy(&pdev->dev, &children_left);
>>>> -
>>>> - /* and put the reference of the find */
>>>> - of_dev_put(pdev);
>>>> + if (of_device_is_compatible(rd->dn, "arm,primecell")) {
>>>> + adev = of_find_amba_device_by_node(rd->dn);
>>>> + if (adev == NULL)
>>>> + return NOTIFY_OK; /* no? not meant for us */
>>>> +
>>>> + /* unregister takes one ref away */
>>>> + of_platform_device_destroy(&adev->dev, &children_left);
>>>> +
>>>> + /* and put the reference of the find */
>>>> + if (adev)
>>>> + put_device(&adev->dev);
>>> of_amba_dev_put() here also
>>>
>>> -Frank
>> Okay, I will create it.
>>>> + } else {
>>>> + pdev = of_find_device_by_node(rd->dn);
>>>> + if (pdev == NULL)
>>>> + return NOTIFY_OK; /* no? not meant for us */
>>>> +
>>>> + /* unregister takes one ref away */
>>>> + of_platform_device_destroy(&pdev->dev, &children_left);
>>>> +
>>>> + /* and put the reference of the find */
>>>> + of_dev_put(pdev);
>>>> + }
>>>> break;
>>>> }
>>>>
>> Thanks
>>
>> Jaewon Kim
>>
>>
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