On 09/20/2016 06:50 AM, Mika Westerberg wrote:
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 :)

Yes, I somehow didn't see that last line. Too early in the morning,
not enough coffee.

Thanks,
Guenter

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