IB/hfi1: Restore EPROM read ability

Partially revert commit d07903174202 ("IB/hfi1: Remove
EPROM functionality from data device"), bringing back
the ability to read from the EPROM.

This code will be used for driver-only acccess to the EPROM, hence
change EPROM read to save to a buffer instead of copy touser. Also
allow any offset and remove missed includes and leftover declarations.

Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

3 files changed, 103 insertions, 3 deletions

diff --git a/drivers/infiniband/hw/hfi1/eprom.c b/drivers/infiniband/hw/hfi1/eprom.c
index 36b77943cbfd..30ecd9481e3a 100644
--- a/drivers/infiniband/hw/hfi1/eprom.c
+++ b/drivers/infiniband/hw/hfi1/eprom.c
@@ -49,7 +49,26 @@
 #include "common.h"
 #include "eprom.h"
 
+/*
+ * The EPROM is logically divided into three partitions:
+ *      partition 0: the first 128K, visible from PCI ROM BAR
+ *      partition 1: 4K config file (sector size)
+ *      partition 2: the rest
+ */
+#define P0_SIZE (128 * 1024)
+#define P1_SIZE   (4 * 1024)
+#define P1_START P0_SIZE
+#define P2_START (P0_SIZE + P1_SIZE)
+
+/* controller page size, in bytes */
+#define EP_PAGE_SIZE 256
+#define EP_PAGE_MASK (EP_PAGE_SIZE - 1)
+#define EP_PAGE_DWORDS (EP_PAGE_SIZE / sizeof(u32))
+
+/* controller commands */
 #define CMD_SHIFT 24
+#define CMD_NOP                     (0)
+#define CMD_READ_DATA(addr)         ((0x03 << CMD_SHIFT) | addr)
 #define CMD_RELEASE_POWERDOWN_NOID  ((0xab << CMD_SHIFT))
 
 /* controller interface speeds */
@@ -61,6 +80,90 @@
  * Double it for safety.
  */
 #define EPROM_TIMEOUT 80000 /* ms */
+
+/*
+ * Read a 256 byte (64 dword) EPROM page.
+ * All callers have verified the offset is at a page boundary.
+ */
+static void read_page(struct hfi1_devdata *dd, u32 offset, u32 *result)
+{
+        int i;
+
+        write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_READ_DATA(offset));
+        for (i = 0; i < EP_PAGE_DWORDS; i++)
+                result[i] = (u32)read_csr(dd, ASIC_EEP_DATA);
+        write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_NOP); /* close open page */
+}
+
+/*
+ * Read length bytes starting at offset from the start of the EPROM.
+ */
+static int read_length(struct hfi1_devdata *dd, u32 start, u32 len, void *dest)
+{
+        u32 buffer[EP_PAGE_DWORDS];
+        u32 end;
+        u32 start_offset;
+        u32 read_start;
+        u32 bytes;
+
+        if (len == 0)
+                return 0;
+
+        end = start + len;
+
+        /*
+         * Make sure the read range is not outside of the controller read
+         * command address range.  Note that '>' is correct below - the end
+         * of the range is OK if it stops at the limit, but no higher.
+         */
+        if (end > (1 << CMD_SHIFT))
+                return -EINVAL;
+
+        /* read the first partial page */
+        start_offset = start & EP_PAGE_MASK;
+        if (start_offset) {
+                /* partial starting page */
+
+                /* align and read the page that contains the start */
+                read_start = start & ~EP_PAGE_MASK;
+                read_page(dd, read_start, buffer);
+
+                /* the rest of the page is available data */
+                bytes = EP_PAGE_SIZE - start_offset;
+
+                if (len <= bytes) {
+                        /* end is within this page */
+                        memcpy(dest, (u8 *)buffer + start_offset, len);
+                        return 0;
+                }
+
+                memcpy(dest, (u8 *)buffer + start_offset, bytes);
+
+                start += bytes;
+                len -= bytes;
+                dest += bytes;
+        }
+        /* start is now page aligned */
+
+        /* read whole pages */
+        while (len >= EP_PAGE_SIZE) {
+                read_page(dd, start, buffer);
+                memcpy(dest, buffer, EP_PAGE_SIZE);
+
+                start += EP_PAGE_SIZE;
+                len -= EP_PAGE_SIZE;
+                dest += EP_PAGE_SIZE;
+        }
+
+        /* read the last partial page */
+        if (len) {
+                read_page(dd, start, buffer);
+                memcpy(dest, buffer, len);
+        }
+
+        return 0;
+}
+
 /*
  * Initialize the EPROM handler.
  */
diff --git a/drivers/infiniband/hw/hfi1/eprom.h b/drivers/infiniband/hw/hfi1/eprom.h
index d41f0b1afb15..b7ac9cee1076 100644
--- a/drivers/infiniband/hw/hfi1/eprom.h
+++ b/drivers/infiniband/hw/hfi1/eprom.h
@@ -45,8 +45,6 @@
  *
  */
 
-struct hfi1_cmd;
 struct hfi1_devdata;
 
 int eprom_init(struct hfi1_devdata *dd);
-int handle_eprom_command(struct file *fp, const struct hfi1_cmd *cmd);
diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index 13bb6a5e4d37..677efa0e8cd6 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -58,7 +58,6 @@
 #include "trace.h"
 #include "user_sdma.h"
 #include "user_exp_rcv.h"
-#include "eprom.h"
 #include "aspm.h"
 #include "mmu_rb.h"