6.15-stable review patch. If anyone has any objections, please let me know.
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From: Haren Myneni haren@linux.ibm.com
[ Upstream commit 41a1452759a8b1121df9cf7310acf31d766ba70b ]
IO hotplug add event is handled in the user space with drmgr tool. After the device is enabled, the user space uses /sys/kernel/dlpar interface with “dt add index <drc_index>” to update the device tree. The kernel interface (dlpar_hp_dt_add()) finds the parent node for the specified ‘drc_index’ from ibm,drc-info property. The recent FW provides this property from 2017 onwards. But KVM guest code in some releases is still using the older SLOF firmware which has ibm,drc-indexes property instead of ibm,drc-info.
If the ibm,drc-info is not available, this patch adds changes to search ‘drc_index’ from the indexes array in ibm,drc-indexes property to support old FW.
Fixes: 02b98ff44a57 ("powerpc/pseries/dlpar: Add device tree nodes for DLPAR IO add") Reported-by: Kowshik Jois kowsjois@linux.ibm.com Signed-off-by: Haren Myneni haren@linux.ibm.com Tested-by: Amit Machhiwal amachhiw@linux.ibm.com Reviewed-by: Tyrel Datwyler tyreld@linux.ibm.com Signed-off-by: Madhavan Srinivasan maddy@linux.ibm.com Link: https://patch.msgid.link/20250531235002.239213-1-haren@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/platforms/pseries/dlpar.c | 52 +++++++++++++++++++++++++- 1 file changed, 50 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c index 213aa26dc8b3..979487da6522 100644 --- a/arch/powerpc/platforms/pseries/dlpar.c +++ b/arch/powerpc/platforms/pseries/dlpar.c @@ -404,6 +404,45 @@ get_device_node_with_drc_info(u32 index) return NULL; }
+static struct device_node * +get_device_node_with_drc_indexes(u32 drc_index) +{ + struct device_node *np = NULL; + u32 nr_indexes, index; + int i, rc; + + for_each_node_with_property(np, "ibm,drc-indexes") { + /* + * First element in the array is the total number of + * DRC indexes returned. + */ + rc = of_property_read_u32_index(np, "ibm,drc-indexes", + 0, &nr_indexes); + if (rc) + goto out_put_np; + + /* + * Retrieve DRC index from the list and return the + * device node if matched with the specified index. + */ + for (i = 0; i < nr_indexes; i++) { + rc = of_property_read_u32_index(np, "ibm,drc-indexes", + i+1, &index); + if (rc) + goto out_put_np; + + if (drc_index == index) + return np; + } + } + + return NULL; + +out_put_np: + of_node_put(np); + return NULL; +} + static int dlpar_hp_dt_add(u32 index) { struct device_node *np, *nodes; @@ -423,10 +462,19 @@ static int dlpar_hp_dt_add(u32 index) goto out; }
+ /* + * Recent FW provides ibm,drc-info property. So search + * for the user specified DRC index from ibm,drc-info + * property. If this property is not available, search + * in the indexes array from ibm,drc-indexes property. + */ np = get_device_node_with_drc_info(index);
- if (!np) - return -EIO; + if (!np) { + np = get_device_node_with_drc_indexes(index); + if (!np) + return -EIO; + }
/* Next, configure the connector. */ nodes = dlpar_configure_connector(cpu_to_be32(index), np);