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>

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.
  */

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);

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"