Re: [PATCH 03/14] cxl/mem: Find device capabilities

Konrad Rzeszutek Wilk
2021-02-01T17:43:56Z

> +static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
> +{
> + struct device *dev = &cxlm->pdev->dev;
> + int cap, cap_count;
> + u64 cap_array;
> +
> + cap_array = readq(cxlm->regs + CXLDEV_CAP_ARRAY_OFFSET);
> + if (CXL_GET_FIELD(cap_array, CXLDEV_CAP_ARRAY_ID) != CXLDEV_CAP_ARRAY_CAP_ID)
> + return -ENODEV;
> +
> + cap_count = CXL_GET_FIELD(cap_array, CXLDEV_CAP_ARRAY_COUNT);
> +
> + for (cap = 1; cap <= cap_count; cap++) {
> + void __iomem *register_block;
> + u32 offset;
> + u16 cap_id;
> +
> + cap_id = readl(cxlm->regs + cap * 0x10) & 0xffff;
> + offset = readl(cxlm->regs + cap * 0x10 + 0x4);
> + register_block = cxlm->regs + offset;
> +
> + switch (cap_id) {
> + case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
> + dev_dbg(dev, "found Status capability (0x%x)\n",
> + offset);

That 80 character limit is no longer a requirement. Can you just make
this one line? And perhaps change 'found' to 'Found' ?

> + cxlm->status.regs = register_block;
> + break;
> + case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
> + dev_dbg(dev, "found Mailbox capability (0x%x)\n",
> + offset);
> + cxlm->mbox.regs = register_block;
> + break;
> + case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
> + dev_dbg(dev,
> + "found Secondary Mailbox capability (0x%x)\n",
> + offset);
> + break;
> + case CXLDEV_CAP_CAP_ID_MEMDEV:
> + dev_dbg(dev, "found Memory Device capability (0x%x)\n",
> + offset);
> + cxlm->mem.regs = register_block;
> + break;
> + default:
> + dev_warn(dev, "Unknown cap ID: %d (0x%x)\n", cap_id,
> + offset);
> + break;
> + }
> + }
> +
> + if (!cxlm->status.regs || !cxlm->mbox.regs || !cxlm->mem.regs) {
> + dev_err(dev, "registers not found: %s%s%s\n",
> + !cxlm->status.regs ? "status " : "",
> + !cxlm->mbox.regs ? "mbox " : "",
> + !cxlm->mem.regs ? "mem" : "");
> + return -ENXIO;
> + }
> +
> + return 0;
> +}
> +
> +static int cxl_mem_setup_mailbox(struct cxl_mem *cxlm)
> +{
> + const int cap = cxl_read_mbox_reg32(cxlm, CXLDEV_MB_CAPS_OFFSET);
> +
> + cxlm->mbox.payload_size =
> + 1 << CXL_GET_FIELD(cap, CXLDEV_MB_CAP_PAYLOAD_SIZE);
> +

I think the static analyzers are not going to be happy that you are not
checking the value of `cap` before using it.

Perhaps you should check that first before doing the manipulations?

> + /* 8.2.8.4.3 */
> + if (cxlm->mbox.payload_size < 256) {

#define for 256?