Commit b015f6bc authored by Tyrel Datwyler's avatar Tyrel Datwyler Committed by Michael Ellerman
Browse files

powerpc/pseries: Add cpu DLPAR support for drc-info property 



Older firmwares provided information about Dynamic Reconfig
Connectors (DRC) through several device tree properties, namely
ibm,drc-types, ibm,drc-indexes, ibm,drc-names, and
ibm,drc-power-domains. New firmwares have the ability to present this
same information in a much condensed format through a device tree
property called ibm,drc-info.

The existing cpu DLPAR hotplug code only understands the older DRC
property format when validating the drc-index of a cpu during a
hotplug add. This updates those code paths to use the ibm,drc-info
property, when present, instead for validation.

Signed-off-by: default avatarTyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1573449697-5448-4-git-send-email-tyreld@linux.ibm.com
parent 775fa495

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

+112 −15
Original line number Diff line number Diff line
@@ -465,17 +465,67 @@ static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index) 
	return found;

}



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

{

	struct property *info;

	struct of_drc_info drc;

	const __be32 *value;

	u32 index;

	int count, i, j;



	info = of_find_property(parent, "ibm,drc-info", NULL);

	if (!info)

		return false;



	value = of_prop_next_u32(info, NULL, &count);



	/* First value of ibm,drc-info is number of drc-info records */

	if (value)

		value++;

	else

		return false;



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

		if (of_read_drc_info_cell(&info, &value, &drc))

			return false;



		if (strncmp(drc.drc_type, "CPU", 3))

			break;



		if (drc_index > drc.last_drc_index)

			continue;



		index = drc.drc_index_start;

		for (j = 0; j < drc.num_sequential_elems; j++) {

			if (drc_index == index)

				return true;



			index += drc.sequential_inc;

		}

	}



	return false;

}



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

{

	bool found = false;

	int rc, index;



	index = 0;

	if (of_find_property(parent, "ibm,drc-info", NULL))

		return drc_info_valid_index(parent, drc_index);



	/* 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 (!found) {

		u32 drc;



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

						index++, &drc);



		if (rc)

			break;
@@ -718,19 +768,52 @@ 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)

static int find_drc_info_cpus_to_add(struct device_node *cpus,

				     struct property *info,

				     u32 *cpu_drcs, u32 cpus_to_add)

{

	struct device_node *parent;

	struct of_drc_info drc;

	const __be32 *value;

	u32 count, drc_index;

	int cpus_found = 0;

	int index, rc;

	int i, j;



	parent = of_find_node_by_path("/cpus");

	if (!parent) {

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

		kfree(cpu_drcs);

	if (!info)

		return -1;



	value = of_prop_next_u32(info, NULL, &count);

	if (value)

		value++;



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

		of_read_drc_info_cell(&info, &value, &drc);

		if (strncmp(drc.drc_type, "CPU", 3))

			break;



		drc_index = drc.drc_index_start;

		for (j = 0; j < drc.num_sequential_elems; j++) {

			if (dlpar_cpu_exists(cpus, drc_index))

				continue;



			cpu_drcs[cpus_found++] = drc_index;



			if (cpus_found == cpus_to_add)

				return cpus_found;



			drc_index += drc.sequential_inc;

		}

	}



	return cpus_found;

}



static int find_drc_index_cpus_to_add(struct device_node *cpus,

				      u32 *cpu_drcs, u32 cpus_to_add)

{

	int cpus_found = 0;

	int index, rc;

	u32 drc_index;



	/* 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
@@ -738,25 +821,25 @@ static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add) 
	 */

	index = 1;

	while (cpus_found < cpus_to_add) {

		u32 drc;

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

						index++, &drc_index);



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

						index++, &drc);

		if (rc)

			break;



		if (dlpar_cpu_exists(parent, drc))

		if (dlpar_cpu_exists(cpus, drc_index))

			continue;



		cpu_drcs[cpus_found++] = drc;

		cpu_drcs[cpus_found++] = drc_index;

	}



	of_node_put(parent);

	return cpus_found;

}



static int dlpar_cpu_add_by_count(u32 cpus_to_add)

{

	struct device_node *parent;

	struct property *info;

	u32 *cpu_drcs;

	int cpus_added = 0;

	int cpus_found;
@@ -768,7 +851,21 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add) 
	if (!cpu_drcs)

		return -EINVAL;



	cpus_found = find_dlpar_cpus_to_add(cpu_drcs, cpus_to_add);

	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;

	}



	info = of_find_property(parent, "ibm,drc-info", NULL);

	if (info)

		cpus_found = find_drc_info_cpus_to_add(parent, info, cpu_drcs, cpus_to_add);

	else

		cpus_found = find_drc_index_cpus_to_add(parent, cpu_drcs, cpus_to_add);



	of_node_put(parent);



	if (cpus_found < cpus_to_add) {

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

			cpus_found, cpus_to_add);

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