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