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SubjectRe: [PATCH 22/24] thunderbolt: Add support for host and device NVM firmware upgrade
On Thu, May 25, 2017 at 03:28:34PM +0200, Greg Kroah-Hartman wrote:
> On Thu, May 18, 2017 at 05:39:12PM +0300, Mika Westerberg wrote:
> > +static int tb_switch_nvm_add(struct tb_switch *sw)
> > +{
> > + struct nvmem_device *nvm_dev;
> > + struct tb_switch_nvm *nvm;
> > + u32 val;
> > + int ret;
> > +
> > + if (!sw->dma_port)
> > + return 0;
> > +
> > + nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
> > + if (!nvm)
> > + return -ENOMEM;
> > +
> > + nvm->id = ida_simple_get(&nvm_ida, 0, 0, GFP_KERNEL);
> > +
> > + /*
> > + * If the switch is in safe-mode the only accessible portion of
> > + * the NVM is the non-active one where userspace is expected to
> > + * write new functional NVM.
> > + */
> > + if (!sw->safe_mode) {
> > + u32 nvm_size, hdr_size;
> > +
> > + ret = dma_port_flash_read(sw->dma_port, NVM_FLASH_SIZE, &val,
> > + sizeof(val));
> > + if (ret)
> > + goto err_ida;
> > +
> > + hdr_size = sw->generation < 3 ? SZ_8K : SZ_16K;
> > + nvm_size = (SZ_1M << (val & 7)) / 8;
> > + nvm_size = (nvm_size - hdr_size) / 2;
> > +
> > + ret = dma_port_flash_read(sw->dma_port, NVM_VERSION, &val,
> > + sizeof(val));
> > + if (ret)
> > + goto err_ida;
> > +
> > + nvm->major = val >> 16 & 0xff;
> > + nvm->minor = val >> 8 & 0xff;
> > +
> > + nvm_dev = register_nvmem(sw, nvm->id, nvm_size, true);
> > + if (IS_ERR(nvm_dev)) {
> > + ret = PTR_ERR(nvm_dev);
> > + goto err_ida;
> > + }
> > + nvm->active = nvm_dev;
> > + }
> > +
> > + nvm_dev = register_nvmem(sw, nvm->id, NVM_MAX_SIZE, false);
> > + if (IS_ERR(nvm_dev)) {
> > + ret = PTR_ERR(nvm_dev);
> > + goto err_nvm_active;
> > + }
> > + nvm->non_active = nvm_dev;
> > +
> > + sw->nvm = nvm;
> > +
> > + ret = sysfs_create_group(&sw->dev.kobj, &nvm_group);
>
> Why are you adding this to the sw device? And doing so _after_ it was
> announced to userspace? Why can't you make it part of the device's
> default groups so that the driver core can handle it properly?

I was thinking those attributes should show up only when we have
successfully created the two NVMem devices. But maybe I can add those
conditionally to the device default groups and make the attributes
return error if the NVM device creation fails.

> Hint, if you ever have to call sysfs_* from within a driver, something
> might really be wrong :)

Understood, thanks.

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