drivers/remoteproc/qcom_pil_info.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2019-2020 Linaro Ltd.
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/module.h>
   7 #include <linux/mutex.h>
   8 #include <linux/of_address.h>
   9 #include <linux/math64.h>
  10 #include "qcom_pil_info.h"
  11
  12 /*
  13  * The PIL relocation information region is used to communicate memory regions
  14  * occupied by co-processor firmware for post mortem crash analysis.
  15  *
  16  * It consists of an array of entries with an 8 byte textual identifier of the
  17  * region followed by a 64 bit base address and 32 bit size, both little
  18  * endian.
  19  */
  20 #define PIL_RELOC_NAME_LEN      8
  21 #define PIL_RELOC_ENTRY_SIZE    (PIL_RELOC_NAME_LEN + sizeof(__le64) + sizeof(__le32))
  22
  23 struct pil_reloc {
  24         void __iomem *base;
  25         size_t num_entries;
  26 };
  27
  28 static struct pil_reloc _reloc __read_mostly;
  29 static DEFINE_MUTEX(pil_reloc_lock);
  30
  31 static int qcom_pil_info_init(void)
  32 {
  33         struct device_node *np;
  34         struct resource imem;
  35         void __iomem *base;
  36         int ret;
  37
  38         /* Already initialized? */
  39         if (_reloc.base)
  40                 return 0;
  41
  42         np = of_find_compatible_node(NULL, NULL, "qcom,pil-reloc-info");
  43         if (!np)
  44                 return -ENOENT;
  45
  46         ret = of_address_to_resource(np, 0, &imem);
  47         of_node_put(np);
  48         if (ret < 0)
  49                 return ret;
  50
  51         base = ioremap(imem.start, resource_size(&imem));
  52         if (!base) {
  53                 pr_err("failed to map PIL relocation info region\n");
  54                 return -ENOMEM;
  55         }
  56
  57         memset_io(base, 0, resource_size(&imem));
  58
  59         _reloc.base = base;
  60         _reloc.num_entries = div_u64(resource_size(&imem), PIL_RELOC_ENTRY_SIZE);
  61
  62         return 0;
  63 }
  64
  65 /**
  66  * qcom_pil_info_store() - store PIL information of image in IMEM
  67  * @image:      name of the image
  68  * @base:       base address of the loaded image
  69  * @size:       size of the loaded image
  70  *
  71  * Return: 0 on success, negative errno on failure
  72  */
  73 int qcom_pil_info_store(const char *image, phys_addr_t base, size_t size)
  74 {
  75         char buf[PIL_RELOC_NAME_LEN];
  76         void __iomem *entry;
  77         int ret;
  78         int i;
  79
  80         mutex_lock(&pil_reloc_lock);
  81         ret = qcom_pil_info_init();
  82         if (ret < 0) {
  83                 mutex_unlock(&pil_reloc_lock);
  84                 return ret;
  85         }
  86
  87         for (i = 0; i < _reloc.num_entries; i++) {
  88                 entry = _reloc.base + i * PIL_RELOC_ENTRY_SIZE;
  89
  90                 memcpy_fromio(buf, entry, PIL_RELOC_NAME_LEN);
  91
  92                 /*
  93                  * An empty record means we didn't find it, given that the
  94                  * records are packed.
  95                  */
  96                 if (!buf[0])
  97                         goto found_unused;
  98
  99                 if (!strncmp(buf, image, PIL_RELOC_NAME_LEN))
 100                         goto found_existing;
 101         }
 102
 103         pr_warn("insufficient PIL info slots\n");
 104         mutex_unlock(&pil_reloc_lock);
 105         return -ENOMEM;
 106
 107 found_unused:
 108         memcpy_toio(entry, image, PIL_RELOC_NAME_LEN);
 109 found_existing:
 110         /* Use two writel() as base is only aligned to 4 bytes on odd entries */
 111         writel(base, entry + PIL_RELOC_NAME_LEN);
 112         writel((u64)base >> 32, entry + PIL_RELOC_NAME_LEN + 4);
 113         writel(size, entry + PIL_RELOC_NAME_LEN + sizeof(__le64));
 114         mutex_unlock(&pil_reloc_lock);
 115
 116         return 0;
 117 }
 118 EXPORT_SYMBOL_GPL(qcom_pil_info_store);
 119
 120 static void __exit pil_reloc_exit(void)
 121 {
 122         mutex_lock(&pil_reloc_lock);
 123         iounmap(_reloc.base);
 124         _reloc.base = NULL;
 125         mutex_unlock(&pil_reloc_lock);
 126 }
 127 module_exit(pil_reloc_exit);
 128
 129 MODULE_DESCRIPTION("Qualcomm PIL relocation info");
 130 MODULE_LICENSE("GPL v2");