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-rw-r--r--arch/powerpc/kernel/prom_parse.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/prom_parse.c b/arch/powerpc/kernel/prom_parse.c
new file mode 100644
index 000000000..9cb7f88df
--- /dev/null
+++ b/arch/powerpc/kernel/prom_parse.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/ioport.h>
+#include <linux/etherdevice.h>
+#include <linux/of_address.h>
+#include <asm/prom.h>
+
+void of_parse_dma_window(struct device_node *dn, const __be32 *dma_window,
+ unsigned long *busno, unsigned long *phys,
+ unsigned long *size)
+{
+ u32 cells;
+ const __be32 *prop;
+
+ /* busno is always one cell */
+ *busno = of_read_number(dma_window, 1);
+ dma_window++;
+
+ prop = of_get_property(dn, "ibm,#dma-address-cells", NULL);
+ if (!prop)
+ prop = of_get_property(dn, "#address-cells", NULL);
+
+ cells = prop ? of_read_number(prop, 1) : of_n_addr_cells(dn);
+ *phys = of_read_number(dma_window, cells);
+
+ dma_window += cells;
+
+ prop = of_get_property(dn, "ibm,#dma-size-cells", NULL);
+ cells = prop ? of_read_number(prop, 1) : of_n_size_cells(dn);
+ *size = of_read_number(dma_window, cells);
+}