static int find_psb_table()

in powernow-k8.c [622:707]

• 62 lines of code
• 10 McCabe index (conditional complexity)

static int find_psb_table(struct powernow_k8_data *data)
{
	struct psb_s *psb;
	unsigned int i;
	u32 mvs;
	u8 maxvid;
	u32 cpst = 0;
	u32 thiscpuid;

	for (i = 0xc0000; i < 0xffff0; i += 0x10) {
		/* Scan BIOS looking for the signature. */
		/* It can not be at ffff0 - it is too big. */

		psb = phys_to_virt(i);
		if (memcmp(psb, PSB_ID_STRING, PSB_ID_STRING_LEN) != 0)
			continue;

		pr_debug("found PSB header at 0x%p\n", psb);

		pr_debug("table vers: 0x%x\n", psb->tableversion);
		if (psb->tableversion != PSB_VERSION_1_4) {
			pr_err(FW_BUG "PSB table is not v1.4\n");
			return -ENODEV;
		}

		pr_debug("flags: 0x%x\n", psb->flags1);
		if (psb->flags1) {
			pr_err(FW_BUG "unknown flags\n");
			return -ENODEV;
		}

		data->vstable = psb->vstable;
		pr_debug("voltage stabilization time: %d(*20us)\n",
				data->vstable);

		pr_debug("flags2: 0x%x\n", psb->flags2);
		data->rvo = psb->flags2 & 3;
		data->irt = ((psb->flags2) >> 2) & 3;
		mvs = ((psb->flags2) >> 4) & 3;
		data->vidmvs = 1 << mvs;
		data->batps = ((psb->flags2) >> 6) & 3;

		pr_debug("ramp voltage offset: %d\n", data->rvo);
		pr_debug("isochronous relief time: %d\n", data->irt);
		pr_debug("maximum voltage step: %d - 0x%x\n", mvs, data->vidmvs);

		pr_debug("numpst: 0x%x\n", psb->num_tables);
		cpst = psb->num_tables;
		if ((psb->cpuid == 0x00000fc0) ||
		    (psb->cpuid == 0x00000fe0)) {
			thiscpuid = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);
			if ((thiscpuid == 0x00000fc0) ||
			    (thiscpuid == 0x00000fe0))
				cpst = 1;
		}
		if (cpst != 1) {
			pr_err(FW_BUG "numpst must be 1\n");
			return -ENODEV;
		}

		data->plllock = psb->plllocktime;
		pr_debug("plllocktime: 0x%x (units 1us)\n", psb->plllocktime);
		pr_debug("maxfid: 0x%x\n", psb->maxfid);
		pr_debug("maxvid: 0x%x\n", psb->maxvid);
		maxvid = psb->maxvid;

		data->numps = psb->numps;
		pr_debug("numpstates: 0x%x\n", data->numps);
		return fill_powernow_table(data,
				(struct pst_s *)(psb+1), maxvid);
	}
	/*
	 * If you see this message, complain to BIOS manufacturer. If
	 * he tells you "we do not support Linux" or some similar
	 * nonsense, remember that Windows 2000 uses the same legacy
	 * mechanism that the old Linux PSB driver uses. Tell them it
	 * is broken with Windows 2000.
	 *
	 * The reference to the AMD documentation is chapter 9 in the
	 * BIOS and Kernel Developer's Guide, which is available on
	 * www.amd.com
	 */
	pr_err(FW_BUG "No PSB or ACPI _PSS objects\n");
	pr_err("Make sure that your BIOS is up to date and Cool'N'Quiet support is enabled in BIOS setup\n");
	return -ENODEV;
}