On Tue, Sep 20, 2016 at 06:37:23AM -0700, Guenter Roeck wrote:
> > + for (i = 0; i < tbl->entries; i++) {
> > + const struct acpi_generic_address *gas;
> > + struct wdat_instruction *instr;
> > + struct list_head *instructions;
> > + unsigned int action;
> > + struct resource r;
> > + int j;
> > +
> > + action = entries[i].action;
> > + if (action >= MAX_WDAT_ACTIONS) {
> > + dev_dbg(&pdev->dev, "Skipping unknown action: %u\n",
> > + action);
> > + continue;
> > + }
> > +
> > + instr = devm_kzalloc(&pdev->dev, sizeof(*instr), GFP_KERNEL);
> > + if (!instr)
> > + return -ENOMEM;
> > +
> > + INIT_LIST_HEAD(&instr->node);
> > + instr->entry = entries[i];
> > +
> > + gas = &entries[i].register_region;
> > +
> > + memset(&r, 0, sizeof(r));
> > + r.start = gas->address;
> > + r.end = r.start + gas->access_width;
> > + if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
> > + r.flags = IORESOURCE_MEM;
> > + } else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
> > + r.flags = IORESOURCE_IO;
> > + } else {
> > + dev_dbg(&pdev->dev, "Unsupported address space: %d\n",
> > + gas->space_id);
> > + continue;
> > + }
> > +
> > + /* Find the matching resource */
> > + for (j = 0; j < pdev->num_resources; j++) {
> > + res = &pdev->resource[j];
> > + if (resource_contains(res, &r)) {
> > + instr->reg = regs[j] + r.start - res->start;
> > + break;
> > + }
> > + }
> > +
> > + if (!instr->reg) {
> > + dev_err(&pdev->dev, "I/O resource not found\n");
> > + return -EINVAL;
> > + }
> > +
> I must be missing something here. What is happening with instr ?
Instr contains the actual instruction from WDAT table. There can be
many.
> > + instructions = wdat->instructions[action];
This will be NULL first time so...
> > + if (!instructions) {
> > + instructions = devm_kzalloc(&pdev->dev,
> > + sizeof(*instructions), GFP_KERNEL);
> > + if (!instructions)
> > + return -ENOMEM;
> > +
> > + INIT_LIST_HEAD(instructions);
> > + wdat->instructions[action] = instructions;
>
> ... and I don't really see how wdat->instructions[action] contains anything
> but
> a zero filled array. Confused :-(.
...we allocate entry for that here. Next time it will not be NULL for
that action.
>
> > + }
> > +
> > + list_add_tail(&instr->node, instructions);
Then we append each instr to the list for this action.
Hope this clarifies :)
