[PATCH 13/15] pstore: pass ramoops configuration to kernel via device tree

[Juergen Borleis <jbe@pengutronix.de>]

From: Philipp Zabel <p.zabel@pengutronix.de>

Instead of setting ramoops module parameters on the kernel command line,
add a /reserved-memory/ramoops node to the device tree via of_fixup.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Documentation-added-by: Juergen Borleis <jbe@pengutronix.de>
---
 Documentation/filesystems/pstore.rst | 10 ++--
 fs/pstore/ram.c                      | 98 +++++++++++++++++++++++++++++-------
 2 files changed, 86 insertions(+), 22 deletions(-)

diff --git a/Documentation/filesystems/pstore.rst b/Documentation/filesystems/pstore.rst
index c128daae9f..00a5a05537 100644
--- a/Documentation/filesystems/pstore.rst
+++ b/Documentation/filesystems/pstore.rst
@@ -42,10 +42,12 @@ written):
 
 To use pstore/RAMOOPS both Barebox and Kernel have to be compiled with pstore
 and RAM backend support. The kernel receives the parameters describing the
-layout over the kernel command line. These parameters are automatically
-generated by Barebox. You can change these parameters in Barebox menuconfig. The
-RAMOOPS parameters for the Kernel are stored in the variable
-global.linux.bootargs.ramoops.
+layout via devicetree or - as a fallback - over the kernel command line.
+To ensure both worlds are using the same memory layout, the required
+configuration data for the kernel is generated on-the-fly prior booting a kernel.
+For the devicetree use case Barebox adapts the kernel's devicetree, for the
+kernel command line fallback the variable ``global.linux.bootargs.ramoops`` is
+created and its content used to build the kernel command line.
 
 You can adapt the *pstore* parameters in Barebox menuconfig.
 
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index fcf6b3087c..3daec0d0d8 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -468,6 +468,66 @@ static int ramoops_parse_dt(struct device_d *dev,
        return 0;
 }
 
+static int ramoops_of_fixup(struct device_node *root, void *data)
+{
+	struct ramoops_platform_data *pdata = data;
+	struct device_node *node;
+	u32 reg[2];
+	int ret;
+
+	node = of_get_child_by_name(root, "reserved-memory");
+	if (!node) {
+		pr_info("Adding reserved-memory node\n");
+		node = of_create_node(root, "/reserved-memory");
+		if (!node)
+			return -ENOMEM;
+
+		of_property_write_u32(node, "#address-cells", 1);
+		of_property_write_u32(node, "#size-cells", 1);
+		of_new_property(node, "ranges", NULL, 0);
+	}
+
+	node = of_get_child_by_name(node, "ramoops");
+	if (!node) {
+		pr_info("Adding ramoops node\n");
+		node = of_create_node(root, "/reserved-memory/ramoops");
+		if (!node)
+			return -ENOMEM;
+	}
+
+	ret = of_property_write_string(node, "compatible", "ramoops");
+	if (ret)
+		return ret;
+	reg[0] = pdata->mem_address;
+	reg[1] = pdata->mem_size;
+	ret = of_property_write_u32_array(node, "reg", reg, 2);
+	if (ret)
+		return ret;
+
+	ret = of_property_write_bool(node, "unbuffered", pdata->mem_type);
+	if (ret)
+		return ret;
+	ret = of_property_write_bool(node, "no-dump-oops", !pdata->dump_oops);
+	if (ret)
+		return ret;
+
+#define store_size(name, field) {					\
+		ret = of_property_write_u32(node, name, field);		\
+		if (ret < 0)						\
+			return ret;					\
+	}
+
+	store_size("record-size", pdata->record_size);
+	store_size("console-size", pdata->console_size);
+	store_size("ftrace-size", pdata->ftrace_size);
+	store_size("pmsg-size", pdata->pmsg_size);
+	store_size("ecc-size", pdata->ecc_info.ecc_size);
+
+#undef store_size
+
+	return 0;
+}
+
 static int ramoops_probe(struct device_d *dev)
 {
 	struct ramoops_platform_data *pdata = dummy_data;
@@ -574,25 +634,27 @@ static int ramoops_probe(struct device_d *dev)
 		cxt->size, (unsigned long long)cxt->phys_addr,
 		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
 
-	scnprintf(kernelargs, sizeof(kernelargs),
-		  "ramoops.record_size=0x%x "
-		  "ramoops.console_size=0x%x "
-		  "ramoops.ftrace_size=0x%x "
-		  "ramoops.pmsg_size=0x%x "
-		  "ramoops.mem_address=0x%llx "
-		  "ramoops.mem_size=0x%lx "
-		  "ramoops.ecc=%d",
-		  cxt->record_size,
-		  cxt->console_size,
-		  cxt->ftrace_size,
-		  cxt->pmsg_size,
-		  (unsigned long long)cxt->phys_addr,
-		  mem_size,
-		  ramoops_ecc);
-	globalvar_add_simple("linux.bootargs.ramoops", kernelargs);
-
-	if (IS_ENABLED(CONFIG_OFTREE))
+	if (!IS_ENABLED(CONFIG_OFTREE)) {
+		scnprintf(kernelargs, sizeof(kernelargs),
+			  "ramoops.record_size=0x%x "
+			  "ramoops.console_size=0x%x "
+			  "ramoops.ftrace_size=0x%x "
+			  "ramoops.pmsg_size=0x%x "
+			  "ramoops.mem_address=0x%llx "
+			  "ramoops.mem_size=0x%lx "
+			  "ramoops.ecc=%d",
+			  cxt->record_size,
+			  cxt->console_size,
+			  cxt->ftrace_size,
+			  cxt->pmsg_size,
+			  (unsigned long long)cxt->phys_addr,
+			  mem_size,
+			  ramoops_ecc);
+		globalvar_add_simple("linux.bootargs.ramoops", kernelargs);
+	} else {
 		of_add_reserve_entry(cxt->phys_addr, cxt->phys_addr + mem_size);
+		of_register_fixup(ramoops_of_fixup, pdata);
+	}
 
 	return 0;
 
-- 
2.11.0


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox