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Commit 90edf184 authored by Nathan Fontenot's avatar Nathan Fontenot Committed by Michael Ellerman
Browse files

powerpc/pseries: Add CPU dlpar add functionality 



Add the ability to hotplug add cpus via rtas hotplug events by either
specifying the drc index of the CPU to add, or providing a count of the
number of CPUs to add.

Signed-off-by: default avatarNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent ac713800

arch/powerpc/platforms/pseries/hotplug-cpu.c

+116 −0
Original line number Diff line number Diff line
@@ -405,6 +405,27 @@ static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index) 
	return found;

}



static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)

{

	bool found = false;

	int rc, index;



	index = 0;

	while (!found) {

		u32 drc;



		rc = of_property_read_u32_index(parent, "ibm,drc-indexes",

						index++, &drc);

		if (rc)

			break;



		if (drc == drc_index)

			found = true;

	}



	return found;

}



static ssize_t dlpar_cpu_add(u32 drc_index)

{

	struct device_node *dn, *parent;
@@ -424,6 +445,12 @@ static ssize_t dlpar_cpu_add(u32 drc_index) 
		return -EINVAL;

	}



	if (!valid_cpu_drc_index(parent, drc_index)) {

		of_node_put(parent);

		pr_warn("Cannot find CPU (drc index %x) to add.\n", drc_index);

		return -EINVAL;

	}



	rc = dlpar_acquire_drc(drc_index);

	if (rc) {

		pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
@@ -683,6 +710,87 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove) 
	return rc;

}



static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)

{

	struct device_node *parent;

	int cpus_found = 0;

	int index, rc;



	parent = of_find_node_by_path("/cpus");

	if (!parent) {

		pr_warn("Could not find CPU root node in device tree\n");

		kfree(cpu_drcs);

		return -1;

	}



	/* Search the ibm,drc-indexes array for possible CPU drcs to

	 * add. Note that the format of the ibm,drc-indexes array is

	 * the number of entries in the array followed by the array

	 * of drc values so we start looking at index = 1.

	 */

	index = 1;

	while (cpus_found < cpus_to_add) {

		u32 drc;



		rc = of_property_read_u32_index(parent, "ibm,drc-indexes",

						index++, &drc);

		if (rc)

			break;



		if (dlpar_cpu_exists(parent, drc))

			continue;



		cpu_drcs[cpus_found++] = drc;

	}



	of_node_put(parent);

	return cpus_found;

}



static int dlpar_cpu_add_by_count(u32 cpus_to_add)

{

	u32 *cpu_drcs;

	int cpus_added = 0;

	int cpus_found;

	int i, rc;



	pr_debug("Attempting to hot-add %d CPUs\n", cpus_to_add);



	cpu_drcs = kcalloc(cpus_to_add, sizeof(*cpu_drcs), GFP_KERNEL);

	if (!cpu_drcs)

		return -EINVAL;



	cpus_found = find_dlpar_cpus_to_add(cpu_drcs, cpus_to_add);

	if (cpus_found < cpus_to_add) {

		pr_warn("Failed to find enough CPUs (%d of %d) to add\n",

			cpus_found, cpus_to_add);

		kfree(cpu_drcs);

		return -EINVAL;

	}



	for (i = 0; i < cpus_to_add; i++) {

		rc = dlpar_cpu_add(cpu_drcs[i]);

		if (rc)

			break;



		cpus_added++;

	}



	if (cpus_added < cpus_to_add) {

		pr_warn("CPU hot-add failed, removing any added CPUs\n");



		for (i = 0; i < cpus_added; i++)

			dlpar_cpu_remove_by_index(cpu_drcs[i]);



		rc = -EINVAL;

	} else {

		rc = 0;

	}



	kfree(cpu_drcs);

	return rc;

}



int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)

{

	u32 count, drc_index;
@@ -702,6 +810,14 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog) 
		else

			rc = -EINVAL;

		break;

	case PSERIES_HP_ELOG_ACTION_ADD:

		if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)

			rc = dlpar_cpu_add_by_count(count);

		else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)

			rc = dlpar_cpu_add(drc_index);

		else

			rc = -EINVAL;

		break;

	default:

		pr_err("Invalid action (%d) specified\n", hp_elog->action);

		rc = -EINVAL;