linux-kernel - [PATCH v2 7/7] soc/fsl/qbman: Update device tree with reserved memory

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Message-ID: <1562187548-32261-8-git-send-email-roy.pledge@nxp.com>
Date:   Wed, 3 Jul 2019 20:59:37 +0000
From:   Roy Pledge <roy.pledge@....com>
To:     "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Leo Li <leoyang.li@....com>
CC:     Roy Pledge <roy.pledge@....com>
Subject: [PATCH v2 7/7] soc/fsl/qbman: Update device tree with reserved memory

When using the reserved memory node in the device tree there are
two options - dynamic or static. If a dynamic allocation was
selected (where the kernel selects the address for the allocation)
convert it to a static allocation by inserting the reg property.
This will ensure the same memory is reused after a kexec()

Signed-off-by: Roy Pledge <roy.pledge@....com>
---
 drivers/soc/fsl/qbman/dpaa_sys.c | 60 ++++++++++++++++++++++++----------------
 1 file changed, 36 insertions(+), 24 deletions(-)

diff --git a/drivers/soc/fsl/qbman/dpaa_sys.c b/drivers/soc/fsl/qbman/dpaa_sys.c
index 3e0a7f3..9dd8bb5 100644
--- a/drivers/soc/fsl/qbman/dpaa_sys.c
+++ b/drivers/soc/fsl/qbman/dpaa_sys.c
@@ -37,41 +37,53 @@
 int qbman_init_private_mem(struct device *dev, int idx, dma_addr_t *addr,
 				size_t *size)
 {
-	int ret;
 	struct device_node *mem_node;
-	u64 size64;
 	struct reserved_mem *rmem;
+	struct property *prop;
+	int len, err;
+	__be32 *res_array;
 
-	ret = of_reserved_mem_device_init_by_idx(dev, dev->of_node, idx);
-	if (ret) {
-		dev_err(dev,
-			"of_reserved_mem_device_init_by_idx(%d) failed 0x%x\n",
-			idx, ret);
-		return -ENODEV;
-	}
-	mem_node = of_parse_phandle(dev->of_node, "memory-region", 0);
-	if (mem_node) {
-		ret = of_property_read_u64(mem_node, "size", &size64);
-		if (ret) {
-			dev_err(dev, "of_address_to_resource fails 0x%x\n",
-			        ret);
-			return -ENODEV;
-		}
-		*size = size64;
-	} else {
+	mem_node = of_parse_phandle(dev->of_node, "memory-region", idx);
+	if (!mem_node) {
 		dev_err(dev, "No memory-region found for index %d\n", idx);
 		return -ENODEV;
 	}
 
 	rmem = of_reserved_mem_lookup(mem_node);
+	if (!rmem) {
+		dev_err(dev, "of_reserved_mem_lookup() returned NULL\n");
+		return -ENODEV;
+	}
 	*addr = rmem->base;
+	*size = rmem->size;
 
 	/*
-	 * Disassociate the reserved memory area from the device
-	 * because a device can only have one DMA memory area. This
-	 * should be fine since the memory is allocated and initialized
-	 * and only ever accessed by the QBMan device from now on
+	 * Check if the reg property exists - if not insert the node
+	 * so upon kexec() the same memory region address will be preserved.
+	 * This is needed because QBMan HW does not allow the base address/
+	 * size to be modified once set.
 	 */
-	of_reserved_mem_device_release(dev);
+	prop = of_find_property(mem_node, "reg", &len);
+	if (!prop) {
+		prop = devm_kzalloc(dev, sizeof(*prop), GFP_KERNEL);
+		if (!prop)
+			return -ENOMEM;
+		prop->value = res_array = devm_kzalloc(dev, sizeof(__be32) * 4,
+						       GFP_KERNEL);
+		if (!prop->value)
+			return -ENOMEM;
+		res_array[0] = cpu_to_be32(upper_32_bits(*addr));
+		res_array[1] = cpu_to_be32(lower_32_bits(*addr));
+		res_array[2] = cpu_to_be32(upper_32_bits(*size));
+		res_array[3] = cpu_to_be32(lower_32_bits(*size));
+		prop->length = sizeof(__be32) * 4;
+		prop->name = devm_kstrdup(dev, "reg", GFP_KERNEL);
+		if (!prop->name)
+			return -ENOMEM;
+		err = of_add_property(mem_node, prop);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
-- 
2.7.4