From a5be5ce0e25439fae3cd42e3d775979547926812 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Thu, 3 Nov 2022 09:25:29 +0100
Subject: [PATCH] firmware/nvram: bcm47xx: support init from IO memory
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Provide NVMEM content to the NVRAM driver from a simple
memory resource. This is necessary to use NVRAM in a memory-
mapped flash device. Patch taken from OpenWrts development
tree.

This patch makes it possible to use memory-mapped NVRAM
on the D-Link DWL-8610AP and the D-Link DIR-890L.

Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
[Added an export for modules potentially using the init symbol]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20221103082529.359084-1-linus.walleij@linaro.org
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/firmware/broadcom/bcm47xx_nvram.c | 18 ++++++++++++++++++
 drivers/nvmem/brcm_nvram.c                |  3 +++
 include/linux/bcm47xx_nvram.h             |  6 ++++++
 3 files changed, 27 insertions(+)

--- a/drivers/firmware/broadcom/bcm47xx_nvram.c
+++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
@@ -110,6 +110,24 @@ found:
 	return 0;
 }
 
+int bcm47xx_nvram_init_from_iomem(void __iomem *nvram_start, size_t res_size)
+{
+	if (nvram_len) {
+		pr_warn("nvram already initialized\n");
+		return -EEXIST;
+	}
+
+	if (!bcm47xx_nvram_is_valid(nvram_start)) {
+		pr_err("No valid NVRAM found\n");
+		return -ENOENT;
+	}
+
+	bcm47xx_nvram_copy(nvram_start, res_size);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bcm47xx_nvram_init_from_iomem);
+
 /*
  * On bcm47xx we need access to the NVRAM very early, so we can't use mtd
  * subsystem to access flash. We can't even use platform device / driver to
--- a/drivers/nvmem/brcm_nvram.c
+++ b/drivers/nvmem/brcm_nvram.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
  */
 
+#include <linux/bcm47xx_nvram.h>
 #include <linux/io.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
@@ -139,6 +140,8 @@ static int brcm_nvram_probe(struct platf
 	if (err)
 		return err;
 
+	bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
+
 	config.dev = dev;
 	config.cells = priv->cells;
 	config.ncells = priv->ncells;
--- a/include/linux/bcm47xx_nvram.h
+++ b/include/linux/bcm47xx_nvram.h
@@ -11,6 +11,7 @@
 #include <linux/vmalloc.h>
 
 #ifdef CONFIG_BCM47XX_NVRAM
+int bcm47xx_nvram_init_from_iomem(void __iomem *nvram_start, size_t res_size);
 int bcm47xx_nvram_init_from_mem(u32 base, u32 lim);
 int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len);
 int bcm47xx_nvram_gpio_pin(const char *name);
@@ -20,6 +21,11 @@ static inline void bcm47xx_nvram_release
 	vfree(nvram);
 };
 #else
+static inline int bcm47xx_nvram_init_from_iomem(void __iomem *nvram_start,
+						size_t res_size)
+{
+	return -ENOTSUPP;
+}
 static inline int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
 {
 	return -ENOTSUPP;