IB/hfi1: Export 8051 memory and LCB registers via debugfs

Both the 8051 memory and LCB register access require multiple
steps and coordination with the driver.  This cannot be safely
done with resource0 alone.

The 8051 memory is exported read-only.  LCB is exported read/write.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@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/debugfs.c

@@ -541,6 +541,114 @@ static ssize_t asic_flags_write(struct file *file, const char __user *buf,
 	return ret;
 }
 
+/* read the dc8051 memory */
+static ssize_t dc8051_memory_read(struct file *file, char __user *buf,
+				  size_t count, loff_t *ppos)
+{
+	struct hfi1_pportdata *ppd = private2ppd(file);
+	ssize_t rval;
+	void *tmp;
+	loff_t start, end;
+
+	/* the checks below expect the position to be positive */
+	if (*ppos < 0)
+		return -EINVAL;
+
+	tmp = kzalloc(DC8051_DATA_MEM_SIZE, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	/*
+	 * Fill in the requested portion of the temporary buffer from the
+	 * 8051 memory.  The 8051 memory read is done in terms of 8 bytes.
+	 * Adjust start and end to fit.  Skip reading anything if out of
+	 * range.
+	 */
+	start = *ppos & ~0x7;	/* round down */
+	if (start < DC8051_DATA_MEM_SIZE) {
+		end = (*ppos + count + 7) & ~0x7; /* round up */
+		if (end > DC8051_DATA_MEM_SIZE)
+			end = DC8051_DATA_MEM_SIZE;
+		rval = read_8051_data(ppd->dd, start, end - start,
+				      (u64 *)(tmp + start));
+		if (rval)
+			goto done;
+	}
+
+	rval = simple_read_from_buffer(buf, count, ppos, tmp,
+				       DC8051_DATA_MEM_SIZE);
+done:
+	kfree(tmp);
+	return rval;
+}
+
+static ssize_t debugfs_lcb_read(struct file *file, char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct hfi1_pportdata *ppd = private2ppd(file);
+	struct hfi1_devdata *dd = ppd->dd;
+	unsigned long total, csr_off;
+	u64 data;
+
+	if (*ppos < 0)
+		return -EINVAL;
+	/* only read 8 byte quantities */
+	if ((count % 8) != 0)
+		return -EINVAL;
+	/* offset must be 8-byte aligned */
+	if ((*ppos % 8) != 0)
+		return -EINVAL;
+	/* do nothing if out of range or zero count */
+	if (*ppos >= (LCB_END - LCB_START) || !count)
+		return 0;
+	/* reduce count if needed */
+	if (*ppos + count > LCB_END - LCB_START)
+		count = (LCB_END - LCB_START) - *ppos;
+
+	csr_off = LCB_START + *ppos;
+	for (total = 0; total < count; total += 8, csr_off += 8) {
+		if (read_lcb_csr(dd, csr_off, (u64 *)&data))
+			break; /* failed */
+		if (put_user(data, (unsigned long __user *)(buf + total)))
+			break;
+	}
+	*ppos += total;
+	return total;
+}
+
+static ssize_t debugfs_lcb_write(struct file *file, const char __user *buf,
+				 size_t count, loff_t *ppos)
+{
+	struct hfi1_pportdata *ppd = private2ppd(file);
+	struct hfi1_devdata *dd = ppd->dd;
+	unsigned long total, csr_off, data;
+
+	if (*ppos < 0)
+		return -EINVAL;
+	/* only write 8 byte quantities */
+	if ((count % 8) != 0)
+		return -EINVAL;
+	/* offset must be 8-byte aligned */
+	if ((*ppos % 8) != 0)
+		return -EINVAL;
+	/* do nothing if out of range or zero count */
+	if (*ppos >= (LCB_END - LCB_START) || !count)
+		return 0;
+	/* reduce count if needed */
+	if (*ppos + count > LCB_END - LCB_START)
+		count = (LCB_END - LCB_START) - *ppos;
+
+	csr_off = LCB_START + *ppos;
+	for (total = 0; total < count; total += 8, csr_off += 8) {
+		if (get_user(data, (unsigned long __user *)(buf + total)))
+			break;
+		if (write_lcb_csr(dd, csr_off, data))
+			break; /* failed */
+	}
+	*ppos += total;
+	return total;
+}
+
 /*
  * read the per-port QSFP data for ppd
  */
@@ -931,6 +1039,8 @@ static const struct counter_info port_cntr_ops[] = {
 	DEBUGFS_XOPS("qsfp2", qsfp2_debugfs_read, qsfp2_debugfs_write,
 		     qsfp2_debugfs_open, qsfp2_debugfs_release),
 	DEBUGFS_OPS("asic_flags", asic_flags_read, asic_flags_write),
+	DEBUGFS_OPS("dc8051_memory", dc8051_memory_read, NULL),
+	DEBUGFS_OPS("lcb", debugfs_lcb_read, debugfs_lcb_write),
 };
 
 static void *_sdma_cpu_list_seq_start(struct seq_file *s, loff_t *pos)