Messages in this thread | | | Date | Fri, 22 Aug 2014 23:26:30 -0500 | From | German Rivera <> | Subject | Re: [RFC PATCH 2/4] drivers/bus: Freescale Management Complex (fsl-mc) bus driver |
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Hi Arnd,
I have posted respin v3 of this patch series to address your lastest of comments. Please see below the resolutions.
Thanks,
German
On 08/21/2014 06:30 AM, Arnd Bergmann wrote: > On Tuesday 19 August 2014, German Rivera wrote: >>>> + * @dev_node: Node in the container's child list >>> >>> Same here: just use the device model's list management instead if you can, >>> or explain why this is needed. >>> >> We still need to keep a per-bus list of child devices (devices contained >> in a given DPRC object). Unless I'm missing something, >> I think the device model's list management links together all the >> devices of the same bus type. We are trying to follow a similar approach >> to the pci_dev/pci_bus structs. > > There are multiple lists in the device handling. device_for_each_child() > should iterate over the children of a particular device using the > klist_children member. > Removed per-bus list of children, and instead use device_for_each_child() as you suggested.
>>>> +/** >>>> + * struct fsl_mc_dprc - Data Path Resource Container (DPRC) object >>>> + * @magic: marker to verify identity of this structure >>>> + * @mc_dev: pointer to MC object device object for this DPRC >>>> + * @mutex: mutex to serialize access to the container. >>>> + * @child_device_count: have the count of devices in this DPRC >>>> + * @child_list: anchor node of list of child devices on this DPRC >>>> + */ >>>> +struct fsl_mc_dprc { >>>> +# define FSL_MC_DPRC_MAGIC FSL_MC_MAGIC('D', 'P', 'R', 'C') >>>> + uint32_t magic; >>>> + struct fsl_mc_device *mc_dev; >>>> + struct mutex mutex; /* serializes access to fields below */ >>>> + uint16_t child_device_count; /* Count of devices in this DPRC */ >>>> + struct list_head child_list; >>>> +}; >>> >>> It's not clear what this represents to me. mc_dev presumably already >>> has a list of children, so why not just use a pointer to mc_dev >>> and remove this structure entirely? >>> >> This structure represents the per-bus (per DPRC object) information. >> It is kind of the equivalent to 'struct pci_bus' in the PCI world. >> I have renamed this struct to 'struct fsl_mc_bus'. > > Ok, I'll look at the new version when I get back to Germany. I still think > that can remove all members of the current structure and just use the > same structure for fsl_mc_bus and fsl_mc_device. If you really need > a small number of extra members beyond what is in the device, you have > two other choices: > By removing the child list from the fsl_mc_bus structure as you suggested, the fsl_mc_bus structure does not need to exist for this patch series. As you rightfully suggested, we can use just one structure (fsl_mc_device) to represent both regular devices (children) and bus devices.
> a) put the members into the device structure as well but not use them > for a device that is not a bus > > b) embed the device structure within the bus structure like > > struct fsl_mc_bus { > int something; > struct fsl_mc_device; > }; > > and then use container_of() to go from the device to the bus where needed > rather than having two objects that are allocated separately. This is > what a lot of other subsystems (not PCI) do. See for instance > platform_device, which often has child devices as well. > In other functionality to be delivered as a follow-on patch series (after this patch series), we will need to track some per-bus information, and we will do so using your "b)" recommendation.
> Arnd >
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