This reads the dma-ranges property from the device tree and sets
dma_offset in the devices accordingly. The code is mostly taken
from the Kernel as of v5.5-rc1. of_dma_configure() is trimmed down
to the cases we want to support currently.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/of/address.c | 109 ++++++++++++++++++++++++++++++++++++++++++
drivers/of/platform.c | 18 +++++++
include/of_address.h | 9 ++++
3 files changed, 136 insertions(+)
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 4e12522a0a..2020f5b7b1 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -458,6 +458,33 @@ bool of_can_translate_address(struct device_node *dev)
}
EXPORT_SYMBOL(of_can_translate_address);
+static struct device_node *__of_get_dma_parent(struct device_node *np)
+{
+ struct of_phandle_args args;
+ int ret, index;
+
+ index = of_property_match_string(np, "interconnect-names", "dma-mem");
+ if (index < 0)
+ return of_get_parent(np);
+
+ ret = of_parse_phandle_with_args(np, "interconnects",
+ "#interconnect-cells",
+ index, &args);
+ if (ret < 0)
+ return of_get_parent(np);
+
+ return args.np;
+}
+
+static struct device_node *of_get_next_dma_parent(struct device_node *np)
+{
+ struct device_node *parent;
+
+ parent = __of_get_dma_parent(np);
+
+ return parent;
+}
+
const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
unsigned int *flags)
{
@@ -586,3 +613,85 @@ void __iomem *of_iomap(struct device_node *np, int index)
return IOMEM(res.start);
}
EXPORT_SYMBOL(of_iomap);
+
+/**
+ * of_dma_get_range - Get DMA range info
+ * @np: device node to get DMA range info
+ * @dma_addr: pointer to store initial DMA address of DMA range
+ * @paddr: pointer to store initial CPU address of DMA range
+ * @size: pointer to store size of DMA range
+ *
+ * Look in bottom up direction for the first "dma-ranges" property
+ * and parse it.
+ * dma-ranges format:
+ * DMA addr (dma_addr) : naddr cells
+ * CPU addr (phys_addr_t) : pna cells
+ * size : nsize cells
+ *
+ * It returns -ENODEV if "dma-ranges" property was not found
+ * for this device in DT.
+ */
+int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *size)
+{
+ struct device_node *node = np;
+ const __be32 *ranges = NULL;
+ int len, naddr, nsize, pna;
+ int ret = 0;
+ bool found_dma_ranges = false;
+ u64 dmaaddr;
+
+ while (node) {
+ ranges = of_get_property(node, "dma-ranges", &len);
+
+ /* Ignore empty ranges, they imply no translation required */
+ if (ranges && len > 0)
+ break;
+
+ /* Once we find 'dma-ranges', then a missing one is an error */
+ if (found_dma_ranges && !ranges) {
+ ret = -ENODEV;
+ goto out;
+ }
+ found_dma_ranges = true;
+
+ node = of_get_next_dma_parent(node);
+ }
+
+ if (!node || !ranges) {
+ pr_debug("no dma-ranges found for node(%pOF)\n", np);
+ ret = -ENODEV;
+ goto out;
+ }
+
+ naddr = of_bus_n_addr_cells(node);
+ nsize = of_bus_n_size_cells(node);
+ pna = of_n_addr_cells(node);
+ if ((len / sizeof(__be32)) % (pna + naddr + nsize)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* dma-ranges format:
+ * DMA addr : naddr cells
+ * CPU addr : pna cells
+ * size : nsize cells
+ */
+ dmaaddr = of_read_number(ranges, naddr);
+ *paddr = of_translate_dma_address(node, ranges + naddr);
+ if (*paddr == OF_BAD_ADDR) {
+ pr_err("translation of DMA address(%llx) to CPU address failed node(%pOF)\n",
+ dmaaddr, np);
+ ret = -EINVAL;
+ goto out;
+ }
+ *dma_addr = dmaaddr;
+
+ *size = of_read_number(ranges + naddr + pna, nsize);
+
+ pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
+ *dma_addr, *paddr, *size);
+
+out:
+
+ return ret;
+}
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index d3795d799a..b1a7eb6730 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -74,6 +74,22 @@ static void of_device_make_bus_id(struct device_d *dev)
}
}
+static void of_dma_configure(struct device_d *dev, struct device_node *np)
+{
+ u64 dma_addr, paddr, size = 0;
+ unsigned long offset;
+ int ret;
+
+ ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
+ if (ret < 0) {
+ dma_addr = offset = 0;
+ } else {
+ offset = paddr - dma_addr;
+ }
+
+ dev->dma_offset = offset;
+}
+
/**
* of_platform_device_create - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
@@ -148,6 +164,8 @@ struct device_d *of_platform_device_create(struct device_node *np,
dev->num_resources = num_reg;
of_device_make_bus_id(dev);
+ of_dma_configure(dev, np);
+
resinval = (-1);
debug("%s: register device %s, io=%pa\n",
diff --git a/include/of_address.h b/include/of_address.h
index ebf3ec2a24..350ecaec82 100644
--- a/include/of_address.h
+++ b/include/of_address.h
@@ -56,6 +56,9 @@ extern struct device_node *of_find_matching_node_by_address(
u64 base_address);
extern void __iomem *of_iomap(struct device_node *np, int index);
+extern int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr,
+ u64 *size);
+
#else /* CONFIG_OFTREE */
static inline u64 of_translate_address(struct device_node *dev,
@@ -99,6 +102,12 @@ static inline void __iomem *of_iomap(struct device_node *np, int index)
return NULL;
}
+static inline int of_dma_get_range(struct device_node *np, u64 *dma_addr,
+ u64 *paddr, u64 *size)
+{
+ return -ENOSYS;
+}
+
#endif /* CONFIG_OFTREE */
#ifdef CONFIG_OF_PCI
--
2.24.0
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