[PATCH 01/23] IB/hfi1: Read new EPROM format

Dennis Dalessandro
2016-12-08T03:32:15Z

From: Dean Luick <dean.luick-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

Add the ability to read the new EPROM format.

Reviewed-by: Easwar Hariharan <easwar.hariharan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dean Luick <dean.luick-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
drivers/infiniband/hw/hfi1/eprom.c | 211 +++++++++++++++++++++++++++++++++++-
1 files changed, 203 insertions(+), 8 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/eprom.c b/drivers/infiniband/hw/hfi1/eprom.c
index e70c223..26da124 100644
--- a/drivers/infiniband/hw/hfi1/eprom.c
+++ b/drivers/infiniband/hw/hfi1/eprom.c
@@ -207,6 +207,40 @@ int eprom_init(struct hfi1_devdata *dd)
/* magic character sequence that trails an image */
#define IMAGE_TRAIL_MAGIC "egamiAPO"

+/* EPROM file types */
+#define HFI1_EFT_PLATFORM_CONFIG 2
+
+/* segment size - 128 KiB */
+#define SEG_SIZE (128 * 1024)
+
+struct hfi1_eprom_footer {
+ u32 oprom_size; /* size of the oprom, in bytes */
+ u16 num_table_entries;
+ u16 version; /* version of this footer */
+ u32 magic; /* must be last */
+};
+
+struct hfi1_eprom_table_entry {
+ u32 type; /* file type */
+ u32 offset; /* file offset from start of EPROM */
+ u32 size; /* file size, in bytes */
+};
+
+/*
+ * Calculate the max number of table entries that will fit within a directory
+ * buffer of size 'dir_size'.
+ */
+#define MAX_TABLE_ENTRIES(dir_size) \
+ (((dir_size) - sizeof(struct hfi1_eprom_footer)) / \
+ sizeof(struct hfi1_eprom_table_entry))
+
+#define DIRECTORY_SIZE(n) (sizeof(struct hfi1_eprom_footer) + \
+ (sizeof(struct hfi1_eprom_table_entry) * (n)))
+
+#define MAGIC4(a, b, c, d) ((d) << 24 | (c) << 16 | (b) << 8 | (a))
+#define FOOTER_MAGIC MAGIC4('e', 'p', 'r', 'm')
+#define FOOTER_VERSION 1
+
/*
* Read all of partition 1. The actual file is at the front. Adjust
* the returned size if a trailing image magic is found.
@@ -242,6 +276,167 @@ static int read_partition_platform_config(struct hfi1_devdata *dd, void **data,
}

/*
+ * The segment magic has been checked. There is a footer and table of
+ * contents present.
+ *
+ * directory is a u32 aligned buffer of size EP_PAGE_SIZE.
+ */
+static int read_segment_platform_config(struct hfi1_devdata *dd,
+ void *directory, void **data, u32 *size)
+{
+ struct hfi1_eprom_footer *footer;
+ struct hfi1_eprom_table_entry *table;
+ struct hfi1_eprom_table_entry *entry;
+ void *buffer = NULL;
+ void *table_buffer = NULL;
+ int ret, i;
+ u32 directory_size;
+ u32 seg_base, seg_offset;
+ u32 bytes_available, ncopied, to_copy;
+
+ /* the footer is at the end of the directory */
+ footer = (struct hfi1_eprom_footer *)
+ (directory + EP_PAGE_SIZE - sizeof(*footer));
+
+ /* make sure the structure version is supported */
+ if (footer->version != FOOTER_VERSION)
+ return -EINVAL;
+
+ /* oprom size cannot be larger than a segment */
+ if (footer->oprom_size >= SEG_SIZE)
+ return -EINVAL;
+
+ /* the file table must fit in a segment with the oprom */
+ if (footer->num_table_entries >
+ MAX_TABLE_ENTRIES(SEG_SIZE - footer->oprom_size))
+ return -EINVAL;
+
+ /* find the file table start, which precedes the footer */
+ directory_size = DIRECTORY_SIZE(footer->num_table_entries);
+ if (directory_size <= EP_PAGE_SIZE) {
+ /* the file table fits into the directory buffer handed in */
+ table = (struct hfi1_eprom_table_entry *)
+ (directory + EP_PAGE_SIZE - directory_size);
+ } else {
+ /* need to allocate and read more */
+ table_buffer = kmalloc(directory_size, GFP_KERNEL);
+ if (!table_buffer)
+ return -ENOMEM;
+ ret = read_length(dd, SEG_SIZE - directory_size,
+ directory_size, table_buffer);
+ if (ret)
+ goto done;
+ table = table_buffer;
+ }
+
+ /* look for the platform configuration file in the table */
+ for (entry = NULL, i = 0; i < footer->num_table_entries; i++) {
+ if (table[i].type == HFI1_EFT_PLATFORM_CONFIG) {
+ entry = &table[i];
+ break;
+ }
+ }
+ if (!entry) {
+ ret = -ENOENT;
+ goto done;
+ }
+
+ /*
+ * Sanity check on the configuration file size - it should never
+ * be larger than 4 KiB.
+ */
+ if (entry->size > (4 * 1024)) {
+ dd_dev_err(dd, "Bad configuration file size 0x%x\n",
+ entry->size);
+ ret = -EINVAL;
+ goto done;
+ }
+
+ /* check for bogus offset and size that wrap when added together */
+ if (entry->offset + entry->size < entry->offset) {
+ dd_dev_err(dd,
+ "Bad configuration file start + size 0x%x+0x%x\n",
+ entry->offset, entry->size);
+ ret = -EINVAL;
+ goto done;
+ }
+
+ /* allocate the buffer to return */
+ buffer = kmalloc(entry->size, GFP_KERNEL);
+ if (!buffer) {
+ ret = -ENOMEM;
+ goto done;
+ }
+
+ /*
+ * Extract the file by looping over segments until it is fully read.
+ */
+ seg_offset = entry->offset % SEG_SIZE;
+ seg_base = entry->offset - seg_offset;
+ ncopied = 0;
+ while (ncopied < entry->size) {
+ /* calculate data bytes available in this segment */
+
+ /* start with the bytes from the current offset to the end */
+ bytes_available = SEG_SIZE - seg_offset;
+ /* subtract off footer and table from segment 0 */
+ if (seg_base == 0) {
+ /*
+ * Sanity check: should not have a starting point
+ * at or within the directory.
+ */
+ if (bytes_available <= directory_size) {
+ dd_dev_err(dd,
+ "Bad configuration file - offset 0x%x within footer+table\n",
+ entry->offset);
+ ret = -EINVAL;
+ goto done;
+ }
+ bytes_available -= directory_size;
+ }
+
+ /* calculate bytes wanted */
+ to_copy = entry->size - ncopied;
+
+ /* max out at the available bytes in this segment */
+ if (to_copy > bytes_available)
+ to_copy = bytes_available;
+
+ /*
+ * Read from the EPROM.
+ *
+ * The sanity check for entry->offset is done in read_length().
+ * The EPROM offset is validated against what the hardware
+ * addressing supports. In addition, if the offset is larger
+ * than the actual EPROM, it silently wraps. It will work
+ * fine, though the reader may not get what they expected
+ * from the EPROM.
+ */
+ ret = read_length(dd, seg_base + seg_offset, to_copy,
+ buffer + ncopied);
+ if (ret)
+ goto done;
+
+ ncopied += to_copy;
+
+ /* set up for next segment */
+ seg_offset = footer->oprom_size;
+ seg_base += SEG_SIZE;
+ }
+
+ /* success */
+ ret = 0;
+ *data = buffer;
+ *size = entry->size;
+
+done:
+ kfree(table_buffer);
+ if (ret)
+ kfree(buffer);
+ return ret;
+}
+
+/*
* Read the platform configuration file from the EPROM.
*
* On success, an allocated buffer containing the data and its size are
@@ -253,6 +448,7 @@ static int read_partition_platform_config(struct hfi1_devdata *dd, void **data,
* -EBUSY - not able to acquire access to the EPROM
* -ENOENT - no recognizable file written
* -ENOMEM - buffer could not be allocated
+ * -EINVAL - invalid EPROM contentents found
*/
int eprom_read_platform_config(struct hfi1_devdata *dd, void **data, u32 *size)
{
@@ -266,21 +462,20 @@ int eprom_read_platform_config(struct hfi1_devdata *dd, void **data, u32 *size)
if (ret)
return -EBUSY;

- /* read the last page of P0 for the EPROM format magic */
- ret = read_length(dd, P1_START - EP_PAGE_SIZE, EP_PAGE_SIZE, directory);
+ /* read the last page of the segment for the EPROM format magic */
+ ret = read_length(dd, SEG_SIZE - EP_PAGE_SIZE, EP_PAGE_SIZE, directory);
if (ret)
goto done;

- /* last dword of P0 contains a magic indicator */
- if (directory[EP_PAGE_DWORDS - 1] == 0) {
+ /* last dword of the segment contains a magic value */
+ if (directory[EP_PAGE_DWORDS - 1] == FOOTER_MAGIC) {
+ /* segment format */
+ ret = read_segment_platform_config(dd, directory, data, size);
+ } else {
/* partition format */
ret = read_partition_platform_config(dd, data, size);
- goto done;
}

- /* nothing recognized */
- ret = -ENOENT;
-
done:
release_chip_resource(dd, CR_EPROM);
return ret;