[PATCH v5 2/4] s390/pci: store DMA offset in bus_dma_region
From: Matthew Rosato
Date: Wed Feb 12 2025 - 16:34:58 EST
PCI devices on s390 have a DMA offset that is reported via CLP. In
preparation for allowing identity domains, setup the bus_dma_region
for all PCI devices using the reported CLP value.
Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
---
arch/s390/pci/pci_bus.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
index 857afbc4828f..3fa113c4ad8f 100644
--- a/arch/s390/pci/pci_bus.c
+++ b/arch/s390/pci/pci_bus.c
@@ -19,6 +19,7 @@
#include <linux/jump_label.h>
#include <linux/pci.h>
#include <linux/printk.h>
+#include <linux/dma-direct.h>
#include <asm/pci_clp.h>
#include <asm/pci_dma.h>
@@ -283,10 +284,34 @@ static struct zpci_bus *zpci_bus_alloc(int topo, bool topo_is_tid)
return zbus;
}
+static void pci_dma_range_setup(struct pci_dev *pdev)
+{
+ struct zpci_dev *zdev = to_zpci(pdev);
+ struct bus_dma_region *map;
+ u64 aligned_end;
+
+ map = kzalloc(sizeof(*map), GFP_KERNEL);
+ if (!map)
+ return;
+
+ map->cpu_start = 0;
+ map->dma_start = PAGE_ALIGN(zdev->start_dma);
+ aligned_end = PAGE_ALIGN_DOWN(zdev->end_dma + 1);
+ if (aligned_end >= map->dma_start)
+ map->size = aligned_end - map->dma_start;
+ else
+ map->size = 0;
+ WARN_ON_ONCE(map->size == 0);
+
+ pdev->dev.dma_range_map = map;
+}
+
void pcibios_bus_add_device(struct pci_dev *pdev)
{
struct zpci_dev *zdev = to_zpci(pdev);
+ pci_dma_range_setup(pdev);
+
/*
* With pdev->no_vf_scan the common PCI probing code does not
* perform PF/VF linking.
--
2.48.1