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From:   Joey Pabalinas <joeypabalinas@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     Joey Pabalinas <joeypabalinas@gmail.com>
Subject: [PATCH 3/4] tty/nozomi: improve code readability and style
Date:   Fri, 23 Mar 2018 14:31:26 -1000
Message-Id: <20180324003127.4287-4-joeypabalinas@gmail.com>
In-Reply-To: <20180324003127.4287-1-joeypabalinas@gmail.com>
References: <20180324003127.4287-1-joeypabalinas@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Improve code clarity by renaming identifiers and reorganizing
function control flow.

Signed-off-by: Joey Pabalinas <joeypabalinas@gmail.com>

 1 file changed, 92 insertions(+), 91 deletions(-)

 1 file changed, 76 insertions(+), 90 deletions(-)

diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index 0fcb4db721d2a42f08..a5074a59d3e3d33e68 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -401,7 +401,7 @@ static inline struct port *get_port_by_tty(const struct tty_struct *tty)
 static void read_mem32(u32 *buf, const void __iomem *mem_addr_start,
 			u32 size_bytes)
 {
-	u32 i = 0;
+	u32 nread = 0;
 	const u32 __iomem *ptr = mem_addr_start;
 	u16 *buf16;
 
@@ -411,30 +411,27 @@ static void read_mem32(u32 *buf, const void __iomem *mem_addr_start,
 	/* shortcut for extremely often used cases */
 	switch (size_bytes) {
 	case 2:	/* 2 bytes */
-		buf16 = (u16 *) buf;
+		buf16 = (u16 *)buf;
 		*buf16 = __le16_to_cpu(readw(ptr));
 		goto out;
-		break;
 	case 4:	/* 4 bytes */
-		*(buf) = __le32_to_cpu(readl(ptr));
+		*buf = __le32_to_cpu(readl(ptr));
 		goto out;
-		break;
 	}
 
-	while (i < size_bytes) {
-		if (size_bytes - i == 2) {
+	for (; nread < size_bytes; buf++, ptr++) {
+		if (size_bytes - nread == 2) {
 			/* Handle 2 bytes in the end */
-			buf16 = (u16 *) buf;
-			*(buf16) = __le16_to_cpu(readw(ptr));
-			i += 2;
+			buf16 = (u16 *)buf;
+			*buf16 = __le16_to_cpu(readw(ptr));
+			nread += 2;
 		} else {
 			/* Read 4 bytes */
-			*(buf) = __le32_to_cpu(readl(ptr));
-			i += 4;
+			*buf = __le32_to_cpu(readl(ptr));
+			nread += 4;
 		}
-		buf++;
-		ptr++;
 	}
+
 out:
 	return;
 }
@@ -447,7 +444,7 @@ static void read_mem32(u32 *buf, const void __iomem *mem_addr_start,
 static u32 write_mem32(void __iomem *mem_addr_start, const u32 *buf,
 			u32 size_bytes)
 {
-	u32 i = 0;
+	u32 nwritten = 0;
 	u32 __iomem *ptr = mem_addr_start;
 	const u16 *buf16;
 
@@ -460,7 +457,6 @@ static u32 write_mem32(void __iomem *mem_addr_start, const u32 *buf,
 		buf16 = (const u16 *)buf;
 		writew(__cpu_to_le16(*buf16), ptr);
 		return 2;
-		break;
 	case 1: /*
 		 * also needs to write 4 bytes in this case
 		 * so falling through..
@@ -468,24 +464,22 @@ static u32 write_mem32(void __iomem *mem_addr_start, const u32 *buf,
 	case 4: /* 4 bytes */
 		writel(__cpu_to_le32(*buf), ptr);
 		return 4;
-		break;
 	}
 
-	while (i < size_bytes) {
-		if (size_bytes - i == 2) {
+	for (; nwritten < size_bytes; buf++, ptr++) {
+		if (size_bytes - nwritten == 2) {
 			/* 2 bytes */
 			buf16 = (const u16 *)buf;
 			writew(__cpu_to_le16(*buf16), ptr);
-			i += 2;
+			nwritten += 2;
 		} else {
 			/* 4 bytes */
 			writel(__cpu_to_le32(*buf), ptr);
-			i += 4;
+			nwritten += 4;
 		}
-		buf++;
-		ptr++;
 	}
-	return i;
+
+	return nwritten;
 }
 
 /* Setup pointers to different channels and also setup buffer sizes. */
@@ -632,9 +626,10 @@ static int nozomi_read_config_table(struct nozomi *dc)
 		return 0;
 	}
 
-	if ((dc->config_table.version == 0)
-	    || (dc->config_table.toggle.enabled == TOGGLE_VALID)) {
+	if (!dc->config_table.version
+			|| dc->config_table.toggle.enabled == TOGGLE_VALID) {
 		int i;
+
 		DBG1("Second phase, configuring card");
 
 		nozomi_setup_memory(dc);
@@ -659,12 +654,14 @@ static int nozomi_read_config_table(struct nozomi *dc)
 
 		dc->state = NOZOMI_STATE_ALLOCATED;
 		dev_info(&dc->pdev->dev, "Initialization OK!\n");
+
 		return 1;
 	}
 
-	if ((dc->config_table.version > 0)
-	    && (dc->config_table.toggle.enabled != TOGGLE_VALID)) {
+	if (dc->config_table.version > 0
+			&& dc->config_table.toggle.enabled != TOGGLE_VALID) {
 		u32 offset = 0;
+
 		DBG1("First phase: pushing upload buffers, clearing download");
 
 		dev_info(&dc->pdev->dev, "Version of card: %d\n",
@@ -752,7 +749,7 @@ static void disable_transmit_dl(enum port_type port, struct nozomi *dc)
  */
 static int send_data(enum port_type index, struct nozomi *dc)
 {
-	u32 size = 0;
+	u32 size;
 	struct port *port = &dc->port[index];
 	const u8 toggle = port->toggle_ul;
 	void __iomem *addr = port->ul_addr[toggle];
@@ -762,7 +759,7 @@ static int send_data(enum port_type index, struct nozomi *dc)
 	size = kfifo_out(&port->fifo_ul, dc->send_buf,
 			   ul_size < SEND_BUF_MAX ? ul_size : SEND_BUF_MAX);
 
-	if (size == 0) {
+	if (!size) {
 		DBG4("No more data to send, disable link:");
 		return 0;
 	}
@@ -770,8 +767,8 @@ static int send_data(enum port_type index, struct nozomi *dc)
 	/* DUMP(buf, size); */
 
 	/* Write length + data */
-	write_mem32(addr, (u32 *) &size, 4);
-	write_mem32(addr + 4, (u32 *) dc->send_buf, size);
+	write_mem32(addr, (u32 *)&size, 4);
+	write_mem32(addr + 4, (u32 *)dc->send_buf, size);
 
 	tty_port_tty_wakeup(&port->port);
 
@@ -781,13 +778,12 @@ static int send_data(enum port_type index, struct nozomi *dc)
 /* If all data has been read, return 1, else 0 */
 static int receive_data(enum port_type index, struct nozomi *dc)
 {
-	u8 buf[RECEIVE_BUF_MAX] = { 0 };
-	int size;
+	u8 buf[RECEIVE_BUF_MAX] = {0};
 	u32 offset = 4;
 	struct port *port = &dc->port[index];
 	void __iomem *addr = port->dl_addr[port->toggle_dl];
 	struct tty_struct *tty = tty_port_tty_get(&port->port);
-	int i, ret;
+	int size, ret, i;
 
 	size = __le32_to_cpu(readl(addr));
 	/*  DBG1( "%d bytes port: %d", size, index); */
@@ -802,14 +798,14 @@ static int receive_data(enum port_type index, struct nozomi *dc)
 		goto put;
 	}
 
-	if (unlikely(size == 0)) {
+	if (unlikely(!size)) {
 		dev_err(&dc->pdev->dev, "size == 0?\n");
 		ret = 1;
 		goto put;
 	}
 
 	while (size > 0) {
-		read_mem32((u32 *) buf, addr + offset, RECEIVE_BUF_MAX);
+		read_mem32((u32 *)buf, addr + offset, RECEIVE_BUF_MAX);
 
 		if (size == 1) {
 			tty_insert_flip_char(&port->port, buf[0], TTY_NORMAL);
@@ -937,9 +933,7 @@ static int receive_flow_control(struct nozomi *dc)
 		DBG1("Disable interrupt (0x%04X) on port: %d",
 			enable_ier, port);
 		disable_transmit_ul(port, dc);
-
 	} else if (old_ctrl.CTS == 0 && ctrl_dl.CTS == 1) {
-
 		if (kfifo_len(&dc->port[port].fifo_ul)) {
 			DBG1("Enable interrupt (0x%04X) on port: %d",
 				enable_ier, port);
@@ -989,7 +983,7 @@ static enum ctrl_port_type port2ctrl(enum port_type port,
 		return CTRL_APP2;
 	default:
 		dev_err(&dc->pdev->dev,
-			"ERROR: send flow control " \
+			"ERROR: send flow control "
 			"received for non-existing port\n");
 	}
 	return CTRL_ERROR;
@@ -1002,23 +996,24 @@ static enum ctrl_port_type port2ctrl(enum port_type port,
  */
 static int send_flow_control(struct nozomi *dc)
 {
-	u32 i, more_flow_control_to_be_updated = 0;
+	u32 more_flow_control_to_be_updated = 0;
+	u32 i;
 	u16 *ctrl;
 
 	for (i = PORT_MDM; i < MAX_PORT; i++) {
 		if (dc->port[i].update_flow_control) {
-			if (more_flow_control_to_be_updated) {
-				/* We have more flow control to be updated */
+			if (more_flow_control_to_be_updated)
 				return 1;
-			}
+
 			dc->port[i].ctrl_ul.port = port2ctrl(i, dc);
 			ctrl = (u16 *)&dc->port[i].ctrl_ul;
-			write_mem32(dc->port[PORT_CTRL].ul_addr[0], \
-				(u32 *) ctrl, 2);
+			write_mem32(dc->port[PORT_CTRL].ul_addr[0],
+					(u32 *)ctrl, 2);
 			dc->port[i].update_flow_control = 0;
 			more_flow_control_to_be_updated = 1;
 		}
 	}
+
 	return 0;
 }
 
@@ -1069,7 +1064,7 @@ static int handle_data_dl(struct nozomi *dc, enum port_type port, u8 *toggle,
  */
 static int handle_data_ul(struct nozomi *dc, enum port_type port, u16 read_iir)
 {
-	u8 *toggle = &(dc->port[port].toggle_ul);
+	u8 *toggle = &dc->port[port].toggle_ul;
 
 	if (*toggle == 0 && read_iir & MDM_UL1) {
 		dc->last_ier &= ~MDM_UL;
@@ -1123,7 +1118,7 @@ static int handle_data_ul(struct nozomi *dc, enum port_type port, u16 read_iir)
 static irqreturn_t interrupt_handler(int irq, void *dev_id)
 {
 	struct nozomi *dc = dev_id;
-	unsigned int a;
+	unsigned int i;
 	u16 read_iir;
 
 	if (!dc)
@@ -1141,10 +1136,9 @@ static irqreturn_t interrupt_handler(int irq, void *dev_id)
 	 */
 	read_iir &= dc->last_ier;
 
-	if (read_iir == 0)
+	if (!read_iir)
 		goto none;
 
-
 	DBG4("%s irq:0x%04X, prev:0x%04X", interrupt2str(read_iir), read_iir,
 		dc->last_ier);
 
@@ -1235,9 +1229,9 @@ static irqreturn_t interrupt_handler(int irq, void *dev_id)
 exit_handler:
 	spin_unlock(&dc->spin_mutex);
 
-	for (a = 0; a < NOZOMI_MAX_PORTS; a++)
-		if (test_and_clear_bit(a, &dc->flip))
-			tty_flip_buffer_push(&dc->port[a].port);
+	for (i = 0; i < NOZOMI_MAX_PORTS; i++)
+		if (test_and_clear_bit(i, &dc->flip))
+			tty_flip_buffer_push(&dc->port[i].port);
 
 	return IRQ_HANDLED;
 none:
@@ -1318,10 +1312,8 @@ static int nozomi_card_init(struct pci_dev *pdev,
 				      const struct pci_device_id *ent)
 {
 	resource_size_t start;
-	int ret;
-	struct nozomi *dc = NULL;
-	int ndev_idx;
-	int i;
+	struct nozomi *dc;
+	int ndev_idx, ret, i;
 
 	dev_dbg(&pdev->dev, "Init, new card found\n");
 
@@ -1352,8 +1344,8 @@ static int nozomi_card_init(struct pci_dev *pdev,
 
 	ret = pci_request_regions(dc->pdev, NOZOMI_NAME);
 	if (ret) {
-		dev_err(&pdev->dev, "I/O address 0x%04x already in use\n",
-			(int) /* nozomi_private.io_addr */ 0);
+		/* nozomi_private.io_addr */
+		dev_err(&pdev->dev, "I/O address 0x%04x already in use\n", 0);
 		goto err_disable_device;
 	}
 
@@ -1429,19 +1421,18 @@ static int nozomi_card_init(struct pci_dev *pdev,
 		port->port.ops = &noz_tty_port_ops;
 		tty_dev = tty_port_register_device(&port->port, ntty_driver,
 				dc->index_start + i, &pdev->dev);
+		if (likely(!IS_ERR(tty_dev)))
+			continue;
 
-		if (IS_ERR(tty_dev)) {
-			ret = PTR_ERR(tty_dev);
-			dev_err(&pdev->dev, "Could not allocate tty?\n");
-			tty_port_destroy(&port->port);
-			goto err_free_tty;
-		}
+		ret = PTR_ERR(tty_dev);
+		dev_err(&pdev->dev, "Could not allocate tty?\n");
+		tty_port_destroy(&port->port);
+		goto err_free_tty;
 	}
 
 	return 0;
-
 err_free_tty:
-	for (i = 0; i < MAX_PORT; ++i) {
+	for (i = 0; i < MAX_PORT; i++) {
 		tty_unregister_device(ntty_driver, dc->index_start + i);
 		tty_port_destroy(&dc->port[i].port);
 	}
@@ -1463,18 +1454,19 @@ static int nozomi_card_init(struct pci_dev *pdev,
 
 static void tty_exit(struct nozomi *dc)
 {
-	unsigned int i;
+	int i;
 
 	DBG1(" ");
 
-	for (i = 0; i < MAX_PORT; ++i)
+	for (i = 0; i < MAX_PORT; i++)
 		tty_port_tty_hangup(&dc->port[i].port, false);
 
 	/* Racy below - surely should wait for scheduled work to be done or
 	   complete off a hangup method ? */
 	while (dc->open_ttys)
 		msleep(1);
-	for (i = 0; i < MAX_PORT; ++i) {
+
+	for (i = 0; i < MAX_PORT; i++) {
 		tty_unregister_device(ntty_driver, dc->index_start + i);
 		tty_port_destroy(&dc->port[i].port);
 	}
@@ -1483,9 +1475,9 @@ static void tty_exit(struct nozomi *dc)
 /* Deallocate memory for one device */
 static void nozomi_card_exit(struct pci_dev *pdev)
 {
-	int i;
-	struct ctrl_ul ctrl;
 	struct nozomi *dc = pci_get_drvdata(pdev);
+	struct ctrl_ul ctrl;
+	int i;
 
 	/* Disable all interrupts */
 	dc->last_ier = 0;
@@ -1559,7 +1551,7 @@ static int ntty_install(struct tty_driver *driver, struct tty_struct *tty)
 	if (!port || !dc || dc->state != NOZOMI_STATE_READY)
 		return -ENODEV;
 	ret = tty_standard_install(driver, tty);
-	if (ret == 0)
+	if (!ret)
 		tty->driver_data = port;
 	return ret;
 }
@@ -1599,7 +1591,7 @@ static void ntty_shutdown(struct tty_port *tport)
 
 	DBG1("close: %d", port->token_dl);
 	spin_lock_irqsave(&dc->spin_mutex, flags);
-	dc->last_ier &= ~(port->token_dl);
+	dc->last_ier &= ~port->token_dl;
 	writew(dc->last_ier, dc->reg_ier);
 	dc->open_ttys--;
 	spin_unlock_irqrestore(&dc->spin_mutex, flags);
@@ -1626,21 +1618,21 @@ static void ntty_hangup(struct tty_struct *tty)
 static int ntty_write(struct tty_struct *tty, const unsigned char *buffer,
 		      int count)
 {
-	int rval = -EINVAL;
 	struct nozomi *dc = get_dc_by_tty(tty);
 	struct port *port = tty->driver_data;
 	unsigned long flags;
+	int rval;
 
 	/* DBG1( "WRITEx: %d, index = %d", count, index); */
 
-	if (!dc || !port)
+	if (unlikely(!dc || !port))
 		return -ENODEV;
 
 	rval = kfifo_in(&port->fifo_ul, (unsigned char *)buffer, count);
 
 	spin_lock_irqsave(&dc->spin_mutex, flags);
 	/* CTS is only valid on the modem channel */
-	if (port == &(dc->port[PORT_MDM])) {
+	if (port == &dc->port[PORT_MDM]) {
 		if (port->ctrl_dl.CTS) {
 			DBG4("Enable interrupt");
 			enable_transmit_ul(tty->index % MAX_PORT, dc);
@@ -1668,13 +1660,12 @@ static int ntty_write(struct tty_struct *tty, const unsigned char *buffer,
 static int ntty_write_room(struct tty_struct *tty)
 {
 	struct port *port = tty->driver_data;
-	int room = 4096;
 	const struct nozomi *dc = get_dc_by_tty(tty);
 
-	if (dc)
-		room = kfifo_avail(&port->fifo_ul);
+	if (unlikely(!dc))
+		return 4096;
 
-	return room;
+	return kfifo_avail(&port->fifo_ul);
 }
 
 /* Gets io control parameters */
@@ -1749,6 +1740,7 @@ static int ntty_tiocgicount(struct tty_struct *tty,
 	icount->parity = cnow.parity;
 	icount->brk = cnow.brk;
 	icount->buf_overrun = cnow.buf_overrun;
+
 	return 0;
 }
 
@@ -1763,7 +1755,6 @@ static int ntty_ioctl(struct tty_struct *tty,
 	switch (cmd) {
 	case TIOCMIWAIT: {
 		struct async_icount cprev = port->tty_icount;
-
 		rval = wait_event_interruptible(port->tty_wait,
 				ntty_cflags_changed(port, arg, &cprev));
 		break;
@@ -1813,16 +1804,11 @@ static s32 ntty_chars_in_buffer(struct tty_struct *tty)
 {
 	struct port *port = tty->driver_data;
 	struct nozomi *dc = get_dc_by_tty(tty);
-	s32 rval = 0;
 
-	if (unlikely(!dc || !port)) {
-		goto exit_in_buffer;
-	}
+	if (unlikely(!dc || !port))
+		return 0;
 
-	rval = kfifo_len(&port->fifo_ul);
-
-exit_in_buffer:
-	return rval;
+	return kfifo_len(&port->fifo_ul);
 }
 
 static const struct tty_port_operations noz_tty_port_ops = {
-- 
2.16.3