powerpc/xive: Use the "ibm, chip-id" property only under PowerNV

The 'chip_id' field of the XIVE CPU structure is used to choose a
target for a source located on the same chip. For that, the XIVE
driver queries the chip identifier from the "ibm,chip-id" property
and compares it to a 'src_chip' field identifying the chip of a
source. This information is only available on the PowerNV platform,
'src_chip' being assigned to XIVE_INVALID_CHIP_ID under pSeries.

The "ibm,chip-id" property is also not available on all platforms. It
was first introduced on PowerNV and later, under QEMU for pSeries/KVM.
However, the property is not part of PAPR and does not exist under
pSeries/PowerVM.

Assign 'chip_id' to XIVE_INVALID_CHIP_ID by default and let the
PowerNV platform override the value with the "ibm,chip-id" property.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210413130352.1183267-1-clg@kaod.org

diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
index b025f42..5046970 100644 (file)
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c
@@ -1413,17 +1413,14 @@ static int xive_prepare_cpu(unsigned int cpu)
 
        xc = per_cpu(xive_cpu, cpu);
        if (!xc) {
-               struct device_node *np;
-
                xc = kzalloc_node(sizeof(struct xive_cpu),
                                  GFP_KERNEL, cpu_to_node(cpu));
                if (!xc)
                        return -ENOMEM;
-               np = of_get_cpu_node(cpu, NULL);
-               if (np)
-                       xc->chip_id = of_get_ibm_chip_id(np);
-               of_node_put(np);
                xc->hw_ipi = XIVE_BAD_IRQ;
+               xc->chip_id = XIVE_INVALID_CHIP_ID;
+               if (xive_ops->prepare_cpu)
+                       xive_ops->prepare_cpu(cpu, xc);
 
                per_cpu(xive_cpu, cpu) = xc;
        }

diff --git a/arch/powerpc/sysdev/xive/native.c b/arch/powerpc/sysdev/xive/native.c
index 05a800a..57e3f15 100644 (file)
--- a/arch/powerpc/sysdev/xive/native.c
+++ b/arch/powerpc/sysdev/xive/native.c
@@ -380,6 +380,11 @@ static void xive_native_update_pending(struct xive_cpu *xc)
        }
 }
 
+static void xive_native_prepare_cpu(unsigned int cpu, struct xive_cpu *xc)
+{
+       xc->chip_id = cpu_to_chip_id(cpu);
+}
+
 static void xive_native_setup_cpu(unsigned int cpu, struct xive_cpu *xc)
 {
        s64 rc;
@@ -462,6 +467,7 @@ static const struct xive_ops xive_native_ops = {
        .match                  = xive_native_match,
        .shutdown               = xive_native_shutdown,
        .update_pending         = xive_native_update_pending,
+       .prepare_cpu            = xive_native_prepare_cpu,
        .setup_cpu              = xive_native_setup_cpu,
        .teardown_cpu           = xive_native_teardown_cpu,
        .sync_source            = xive_native_sync_source,

diff --git a/arch/powerpc/sysdev/xive/xive-internal.h b/arch/powerpc/sysdev/xive/xive-internal.h
index b3a456f..504e7ed 100644 (file)
--- a/arch/powerpc/sysdev/xive/xive-internal.h
+++ b/arch/powerpc/sysdev/xive/xive-internal.h
@@ -44,6 +44,7 @@ struct xive_ops {
                                  u32 *sw_irq);
        int     (*setup_queue)(unsigned int cpu, struct xive_cpu *xc, u8 prio);
        void    (*cleanup_queue)(unsigned int cpu, struct xive_cpu *xc, u8 prio);
+       void    (*prepare_cpu)(unsigned int cpu, struct xive_cpu *xc);
        void    (*setup_cpu)(unsigned int cpu, struct xive_cpu *xc);
        void    (*teardown_cpu)(unsigned int cpu, struct xive_cpu *xc);
        bool    (*match)(struct device_node *np);