net: ipa: Grab IMEM slice base/size from DTS

This is a detail that differ per chip, and not per IPA version (and
there are cases of the same IPA versions being implemented across very
very very different SoCs).

This region isn't actually used by the driver, but we most definitely
want to iommu-map it, so that IPA can poke at the data within.

Reviewed-by: Alex Elder <[e-mail]>
Acked-by: Dmitry Baryshkov <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Signed-off-by: Konrad Dybcio <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ipa/ipa_data.h

···
 struct ipa_mem_data {
 	u32 local_count;
 	const struct ipa_mem *local;
-	u32 imem_addr;
-	u32 imem_size;
+
+	/* These values are now passed via DT, but to support
+	 * older systems we must allow this to be specified here.
+	 */
+	u32 imem_addr; /* DEPRECATED */
+	u32 imem_size; /* DEPRECATED */
+
 	u32 smem_size;
 };
 

drivers/net/ipa/ipa_mem.c

···
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/iommu.h>
+#include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 
···
 int ipa_mem_init(struct ipa *ipa, struct platform_device *pdev,
 		 const struct ipa_mem_data *mem_data)
 {
+	struct device_node *ipa_slice_np;
 	struct device *dev = &pdev->dev;
+	u32 imem_base, imem_size;
 	struct resource *res;
 	int ret;
 
···
 	ipa->mem_addr = res->start;
 	ipa->mem_size = resource_size(res);
 
-	ret = ipa_imem_init(ipa, mem_data->imem_addr, mem_data->imem_size);
+	ipa_slice_np = of_parse_phandle(dev->of_node, "sram", 0);
+	if (ipa_slice_np) {
+		struct resource sram_res;
+
+		ret = of_address_to_resource(ipa_slice_np, 0, &sram_res);
+		of_node_put(ipa_slice_np);
+		if (ret)
+			goto err_unmap;
+
+		imem_base = sram_res.start;
+		imem_size = resource_size(&sram_res);
+	} else {
+		/* Backwards compatibility for DTs lacking
+		 * an explicit reference
+		 */
+		imem_base = mem_data->imem_addr;
+		imem_size = mem_data->imem_size;
+	}
+
+	ret = ipa_imem_init(ipa, imem_base, imem_size);
 	if (ret)
 		goto err_unmap;