Hi Dann,

quoted

+ */
+static int
+hisilpc_target_in(struct hisilpc_dev *lpcdev, struct lpc_cycle_para *para,
+		  unsigned long ptaddr, unsigned char *buf,
+		  unsigned long opcnt)
+{
+	unsigned long cnt_per_trans;
+	unsigned int cmd_word;
+	unsigned int waitcnt;
+	int ret;
+
+	if (!buf || !opcnt || !para || !para->csize || !lpcdev)
+		return -EINVAL;
+
+	cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_READ;
+	waitcnt = LPC_PEROP_WAITCNT;
+	if (!(para->opflags & FG_INCRADDR_LPC)) {
+		cmd_word |= LPC_CMD_SAMEADDR;
+		waitcnt = LPC_MAX_WAITCNT;
+	}
+
+	ret = 0;
+	cnt_per_trans = (para->csize == 1) ? opcnt : para->csize;
+	for (; opcnt && !ret; cnt_per_trans = para->csize) {
+		unsigned long flags;
+
+		/* whole operation must be atomic */
+		spin_lock_irqsave(&lpcdev->cycle_lock, flags);
+
+		writel_relaxed(cnt_per_trans, lpcdev->membase + LPC_REG_OP_LEN);
+
+		writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
+
+		writel_relaxed(ptaddr, lpcdev->membase + LPC_REG_ADDR);
+
+		writel(LPC_START_WORK, lpcdev->membase + LPC_REG_START);
+
+		/* whether the operation is finished */
+		ret = wait_lpc_idle(lpcdev->membase, waitcnt);
+		if (!ret) {
+			opcnt -= cnt_per_trans;

Do we need to check for an underflow here?

I think that underflow is ensured not to happen.

Regardless, I find this code hard to follow myself, so I will rewrite a 
bit of this to make it more straightforward.

quoted

+			for (cnt_per_trans--; cnt_per_trans--; buf++)
+				*buf = readb_relaxed(lpcdev->membase +
+					LPC_REG_RDATA);
+			*buf = readb(lpcdev->membase + LPC_REG_RDATA);
+		}
+
+		spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
+	}
+
+	return ret;
+}
+
+/*
+ * hisilpc_target_out - trigger a series of lpc cycles to write required
+ *			data to target peripheral.
+ * @lpcdev: pointer to hisi lpc device
+ * @para: some parameters used to control the lpc I/O operations
+ * @ptaddr: the lpc I/O target port address
+ * @buf: where the data to be written is stored
+ * @opcnt: how many I/O operations required
+ *
+ * Only one byte data is read each I/O operation.

s/read/written/ ?

Right

quoted

+ * Returns 0 on success, non-zero on fail.
+ *
+ */
+static int
+hisilpc_target_out(struct hisilpc_dev *lpcdev, struct lpc_cycle_para *para,
+		   unsigned long ptaddr, const unsigned char *buf,
+		   unsigned long opcnt)
+{
+	unsigned long cnt_per_trans;
+	unsigned int cmd_word;
+	unsigned int waitcnt;
+	int ret;
+
+	if (!buf || !opcnt || !para || !lpcdev)
+		return -EINVAL;
+
+	/* default is increasing address */
+	cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_WRITE;
+	waitcnt = LPC_PEROP_WAITCNT;
+	if (!(para->opflags & FG_INCRADDR_LPC)) {
+		cmd_word |= LPC_CMD_SAMEADDR;
+		waitcnt = LPC_MAX_WAITCNT;
+	}
+
+	ret = 0;
+	cnt_per_trans = (para->csize == 1) ? opcnt : para->csize;
+	for (; opcnt && !ret; cnt_per_trans = para->csize) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&lpcdev->cycle_lock, flags);
+
+		writel_relaxed(cnt_per_trans, lpcdev->membase + LPC_REG_OP_LEN);
+		writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
+		writel_relaxed(ptaddr, lpcdev->membase + LPC_REG_ADDR);
+
+		opcnt -= cnt_per_trans;

Underflow check needed?

As above

 -dann

Thanks,
John