remoteproc: qcom: Introduce helper to store pil info in IMEM

A region in IMEM is used to communicate load addresses of remoteproc to
post mortem debug tools. Implement a helper function that can be used to
store this information in order to enable these tools to process
collected ramdumps.

Reviewed-by: Mathieu Poirier <[email protected]>
Reviewed-by: Vinod Koul <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

drivers/remoteproc/Kconfig

@@ -116,6 +116,9 @@ config KEYSTONE_REMOTEPROC
 	  It's safe to say N here if you're not interested in the Keystone
 	  DSPs or just want to use a bare minimum kernel.
 
+config QCOM_PIL_INFO
+	tristate
+
 config QCOM_RPROC_COMMON
 	tristate
 

drivers/remoteproc/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_OMAP_REMOTEPROC)		+= omap_remoteproc.o
 obj-$(CONFIG_WKUP_M3_RPROC)		+= wkup_m3_rproc.o
 obj-$(CONFIG_DA8XX_REMOTEPROC)		+= da8xx_remoteproc.o
 obj-$(CONFIG_KEYSTONE_REMOTEPROC)	+= keystone_remoteproc.o
+obj-$(CONFIG_QCOM_PIL_INFO)		+= qcom_pil_info.o
 obj-$(CONFIG_QCOM_RPROC_COMMON)		+= qcom_common.o
 obj-$(CONFIG_QCOM_Q6V5_COMMON)		+= qcom_q6v5.o
 obj-$(CONFIG_QCOM_Q6V5_ADSP)		+= qcom_q6v5_adsp.o

drivers/remoteproc/qcom_pil_info.c

@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2020 Linaro Ltd.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_address.h>
+#include "qcom_pil_info.h"
+
+/*
+ * The PIL relocation information region is used to communicate memory regions
+ * occupied by co-processor firmware for post mortem crash analysis.
+ *
+ * It consists of an array of entries with an 8 byte textual identifier of the
+ * region followed by a 64 bit base address and 32 bit size, both little
+ * endian.
+ */
+#define PIL_RELOC_NAME_LEN	8
+#define PIL_RELOC_ENTRY_SIZE	(PIL_RELOC_NAME_LEN + sizeof(__le64) + sizeof(__le32))
+
+struct pil_reloc {
+	void __iomem *base;
+	size_t num_entries;
+};
+
+static struct pil_reloc _reloc __read_mostly;
+static DEFINE_MUTEX(pil_reloc_lock);
+
+static int qcom_pil_info_init(void)
+{
+	struct device_node *np;
+	struct resource imem;
+	void __iomem *base;
+	int ret;
+
+	/* Already initialized? */
+	if (_reloc.base)
+		return 0;
+
+	np = of_find_compatible_node(NULL, NULL, "qcom,pil-reloc-info");
+	if (!np)
+		return -ENOENT;
+
+	ret = of_address_to_resource(np, 0, &imem);
+	of_node_put(np);
+	if (ret < 0)
+		return ret;
+
+	base = ioremap(imem.start, resource_size(&imem));
+	if (!base) {
+		pr_err("failed to map PIL relocation info region\n");
+		return -ENOMEM;
+	}
+
+	memset_io(base, 0, resource_size(&imem));
+
+	_reloc.base = base;
+	_reloc.num_entries = resource_size(&imem) / PIL_RELOC_ENTRY_SIZE;
+
+	return 0;
+}
+
+/**
+ * qcom_pil_info_store() - store PIL information of image in IMEM
+ * @image:	name of the image
+ * @base:	base address of the loaded image
+ * @size:	size of the loaded image
+ *
+ * Return: 0 on success, negative errno on failure
+ */
+int qcom_pil_info_store(const char *image, phys_addr_t base, size_t size)
+{
+	char buf[PIL_RELOC_NAME_LEN];
+	void __iomem *entry;
+	int ret;
+	int i;
+
+	mutex_lock(&pil_reloc_lock);
+	ret = qcom_pil_info_init();
+	if (ret < 0) {
+		mutex_unlock(&pil_reloc_lock);
+		return ret;
+	}
+
+	for (i = 0; i < _reloc.num_entries; i++) {
+		entry = _reloc.base + i * PIL_RELOC_ENTRY_SIZE;
+
+		memcpy_fromio(buf, entry, PIL_RELOC_NAME_LEN);
+
+		/*
+		 * An empty record means we didn't find it, given that the
+		 * records are packed.
+		 */
+		if (!buf[0])
+			goto found_unused;
+
+		if (!strncmp(buf, image, PIL_RELOC_NAME_LEN))
+			goto found_existing;
+	}
+
+	pr_warn("insufficient PIL info slots\n");
+	mutex_unlock(&pil_reloc_lock);
+	return -ENOMEM;
+
+found_unused:
+	memcpy_toio(entry, image, PIL_RELOC_NAME_LEN);
+found_existing:
+	/* Use two writel() as base is only aligned to 4 bytes on odd entries */
+	writel(base, entry + PIL_RELOC_NAME_LEN);
+	writel(base >> 32, entry + PIL_RELOC_NAME_LEN + 4);
+	writel(size, entry + PIL_RELOC_NAME_LEN + sizeof(__le64));
+	mutex_unlock(&pil_reloc_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qcom_pil_info_store);
+
+static void __exit pil_reloc_exit(void)
+{
+	mutex_lock(&pil_reloc_lock);
+	iounmap(_reloc.base);
+	_reloc.base = NULL;
+	mutex_unlock(&pil_reloc_lock);
+}
+module_exit(pil_reloc_exit);
+
+MODULE_DESCRIPTION("Qualcomm PIL relocation info");
+MODULE_LICENSE("GPL v2");

drivers/remoteproc/qcom_pil_info.h

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __QCOM_PIL_INFO_H__
+#define __QCOM_PIL_INFO_H__
+
+#include <linux/types.h>
+
+int qcom_pil_info_store(const char *image, phys_addr_t base, size_t size);
+
+#endif