[PATCH v3 2/3] s390/pci: store DMA offset in bus_dma_region

Matthew Rosato
2025-01-24T20:17:37Z

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@linux.ibm.com>
---
arch/s390/pci/pci_bus.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
index d5ace00d10f0..51fa993b64fc 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>
@@ -284,10 +285,27 @@ 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;
+
+ map = kzalloc(sizeof(*map), GFP_KERNEL);
+ if (!map)
+ return;
+
+ map->cpu_start = 0;
+ map->dma_start = PAGE_ALIGN(zdev->start_dma);
+ map->size = zdev->end_dma - zdev->start_dma + 1;
+ 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