drivers/remoteproc/qcom_pil_info.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (c) 2019-2020 Linaro Ltd.
0004  */
0005 #include <linux/kernel.h>
0006 #include <linux/module.h>
0007 #include <linux/mutex.h>
0008 #include <linux/of_address.h>
0009 #include "qcom_pil_info.h"
0010
0011 /*
0012  * The PIL relocation information region is used to communicate memory regions
0013  * occupied by co-processor firmware for post mortem crash analysis.
0014  *
0015  * It consists of an array of entries with an 8 byte textual identifier of the
0016  * region followed by a 64 bit base address and 32 bit size, both little
0017  * endian.
0018  */
0019 #define PIL_RELOC_NAME_LEN  8
0020 #define PIL_RELOC_ENTRY_SIZE    (PIL_RELOC_NAME_LEN + sizeof(__le64) + sizeof(__le32))
0021
0022 struct pil_reloc {
0023     void __iomem *base;
0024     size_t num_entries;
0025 };
0026
0027 static struct pil_reloc _reloc __read_mostly;
0028 static DEFINE_MUTEX(pil_reloc_lock);
0029
0030 static int qcom_pil_info_init(void)
0031 {
0032     struct device_node *np;
0033     struct resource imem;
0034     void __iomem *base;
0035     int ret;
0036
0037     /* Already initialized? */
0038     if (_reloc.base)
0039         return 0;
0040
0041     np = of_find_compatible_node(NULL, NULL, "qcom,pil-reloc-info");
0042     if (!np)
0043         return -ENOENT;
0044
0045     ret = of_address_to_resource(np, 0, &imem);
0046     of_node_put(np);
0047     if (ret < 0)
0048         return ret;
0049
0050     base = ioremap(imem.start, resource_size(&imem));
0051     if (!base) {
0052         pr_err("failed to map PIL relocation info region\n");
0053         return -ENOMEM;
0054     }
0055
0056     memset_io(base, 0, resource_size(&imem));
0057
0058     _reloc.base = base;
0059     _reloc.num_entries = (u32)resource_size(&imem) / PIL_RELOC_ENTRY_SIZE;
0060
0061     return 0;
0062 }
0063
0064 /**
0065  * qcom_pil_info_store() - store PIL information of image in IMEM
0066  * @image:  name of the image
0067  * @base:   base address of the loaded image
0068  * @size:   size of the loaded image
0069  *
0070  * Return: 0 on success, negative errno on failure
0071  */
0072 int qcom_pil_info_store(const char *image, phys_addr_t base, size_t size)
0073 {
0074     char buf[PIL_RELOC_NAME_LEN];
0075     void __iomem *entry;
0076     int ret;
0077     int i;
0078
0079     mutex_lock(&pil_reloc_lock);
0080     ret = qcom_pil_info_init();
0081     if (ret < 0) {
0082         mutex_unlock(&pil_reloc_lock);
0083         return ret;
0084     }
0085
0086     for (i = 0; i < _reloc.num_entries; i++) {
0087         entry = _reloc.base + i * PIL_RELOC_ENTRY_SIZE;
0088
0089         memcpy_fromio(buf, entry, PIL_RELOC_NAME_LEN);
0090
0091         /*
0092          * An empty record means we didn't find it, given that the
0093          * records are packed.
0094          */
0095         if (!buf[0])
0096             goto found_unused;
0097
0098         if (!strncmp(buf, image, PIL_RELOC_NAME_LEN))
0099             goto found_existing;
0100     }
0101
0102     pr_warn("insufficient PIL info slots\n");
0103     mutex_unlock(&pil_reloc_lock);
0104     return -ENOMEM;
0105
0106 found_unused:
0107     memcpy_toio(entry, image, strnlen(image, PIL_RELOC_NAME_LEN));
0108 found_existing:
0109     /* Use two writel() as base is only aligned to 4 bytes on odd entries */
0110     writel(base, entry + PIL_RELOC_NAME_LEN);
0111     writel((u64)base >> 32, entry + PIL_RELOC_NAME_LEN + 4);
0112     writel(size, entry + PIL_RELOC_NAME_LEN + sizeof(__le64));
0113     mutex_unlock(&pil_reloc_lock);
0114
0115     return 0;
0116 }
0117 EXPORT_SYMBOL_GPL(qcom_pil_info_store);
0118
0119 static void __exit pil_reloc_exit(void)
0120 {
0121     mutex_lock(&pil_reloc_lock);
0122     iounmap(_reloc.base);
0123     _reloc.base = NULL;
0124     mutex_unlock(&pil_reloc_lock);
0125 }
0126 module_exit(pil_reloc_exit);
0127
0128 MODULE_DESCRIPTION("Qualcomm PIL relocation info");
0129 MODULE_LICENSE("GPL v2");