[PATCH 1/4] IB/hfi1: Restore EPROM read ability

[Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

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

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.

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 |   59 ++++++++++++++++++++++++++++++++++++
 1 files changed, 59 insertions(+), 0 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/eprom.c b/drivers/infiniband/hw/hfi1/eprom.c
index 36b7794..5a11bee 100644
--- a/drivers/infiniband/hw/hfi1/eprom.c
+++ b/drivers/infiniband/hw/hfi1/eprom.c
@@ -49,7 +49,25 @@
 #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 EEP_PAGE_MASK (EP_PAGE_SIZE - 1)
+
+/* 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 +79,47 @@
  * 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_SIZE / sizeof(u32); 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.  Copy to user address addr.
+ */
+static int read_length(struct hfi1_devdata *dd, u32 start, u32 len, u64 addr)
+{
+	u32 offset;
+	u32 buffer[EP_PAGE_SIZE / sizeof(u32)];
+	int ret = 0;
+
+	/* reject anything not on an EPROM page boundary */
+	if ((start & EEP_PAGE_MASK) || (len & EEP_PAGE_MASK))
+		return -EINVAL;
+
+	for (offset = 0; offset < len; offset += EP_PAGE_SIZE) {
+		read_page(dd, start + offset, buffer);
+		if (copy_to_user((void __user *)(addr + offset),
+				 buffer, EP_PAGE_SIZE)) {
+			ret = -EFAULT;
+			goto done;
+		}
+	}
+
+done:
+	return ret;
+}
+
 /*
  * Initialize the EPROM handler.
  */

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