[PATCH 03/12] nfc: port100: constify several pointers

From: Krzysztof Kozlowski
Date: Thu Jul 29 2021 - 06:40:48 EST


Several functions do not modify pointed data so arguments and local
variables can be const for correctness and safety.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx>
---
drivers/nfc/port100.c | 37 ++++++++++++++++++++-----------------
1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/drivers/nfc/port100.c b/drivers/nfc/port100.c
index ccb5c5fab905..517376c43b86 100644
--- a/drivers/nfc/port100.c
+++ b/drivers/nfc/port100.c
@@ -526,7 +526,7 @@ static inline u8 port100_checksum(u16 value)
}

/* The rule: sum(data elements) + checksum = 0 */
-static u8 port100_data_checksum(u8 *data, int datalen)
+static u8 port100_data_checksum(const u8 *data, int datalen)
{
u8 sum = 0;
int i;
@@ -568,10 +568,10 @@ static void port100_tx_update_payload_len(void *_frame, int len)
le16_add_cpu(&frame->datalen, len);
}

-static bool port100_rx_frame_is_valid(void *_frame)
+static bool port100_rx_frame_is_valid(const void *_frame)
{
u8 checksum;
- struct port100_frame *frame = _frame;
+ const struct port100_frame *frame = _frame;

if (frame->start_frame != cpu_to_be16(PORT100_FRAME_SOF) ||
frame->extended_frame != cpu_to_be16(PORT100_FRAME_EXT))
@@ -589,23 +589,24 @@ static bool port100_rx_frame_is_valid(void *_frame)
return true;
}

-static bool port100_rx_frame_is_ack(struct port100_ack_frame *frame)
+static bool port100_rx_frame_is_ack(const struct port100_ack_frame *frame)
{
return (frame->start_frame == cpu_to_be16(PORT100_FRAME_SOF) &&
frame->ack_frame == cpu_to_be16(PORT100_FRAME_ACK));
}

-static inline int port100_rx_frame_size(void *frame)
+static inline int port100_rx_frame_size(const void *frame)
{
- struct port100_frame *f = frame;
+ const struct port100_frame *f = frame;

return sizeof(struct port100_frame) + le16_to_cpu(f->datalen) +
PORT100_FRAME_TAIL_LEN;
}

-static bool port100_rx_frame_is_cmd_response(struct port100 *dev, void *frame)
+static bool port100_rx_frame_is_cmd_response(const struct port100 *dev,
+ const void *frame)
{
- struct port100_frame *f = frame;
+ const struct port100_frame *f = frame;

return (PORT100_FRAME_CMD(f) == PORT100_CMD_RESPONSE(dev->cmd->code));
}
@@ -655,7 +656,8 @@ static void port100_recv_response(struct urb *urb)
schedule_work(&dev->cmd_complete_work);
}

-static int port100_submit_urb_for_response(struct port100 *dev, gfp_t flags)
+static int port100_submit_urb_for_response(const struct port100 *dev,
+ gfp_t flags)
{
dev->in_urb->complete = port100_recv_response;

@@ -666,7 +668,7 @@ static void port100_recv_ack(struct urb *urb)
{
struct port100 *dev = urb->context;
struct port100_cmd *cmd = dev->cmd;
- struct port100_ack_frame *in_frame;
+ const struct port100_ack_frame *in_frame;
int rc;

cmd->status = urb->status;
@@ -708,7 +710,7 @@ static void port100_recv_ack(struct urb *urb)
schedule_work(&dev->cmd_complete_work);
}

-static int port100_submit_urb_for_ack(struct port100 *dev, gfp_t flags)
+static int port100_submit_urb_for_ack(const struct port100 *dev, gfp_t flags)
{
dev->in_urb->complete = port100_recv_ack;

@@ -753,8 +755,9 @@ static int port100_send_ack(struct port100 *dev)
return rc;
}

-static int port100_send_frame_async(struct port100 *dev, struct sk_buff *out,
- struct sk_buff *in, int in_len)
+static int port100_send_frame_async(struct port100 *dev,
+ const struct sk_buff *out,
+ const struct sk_buff *in, int in_len)
{
int rc;

@@ -960,7 +963,7 @@ static void port100_abort_cmd(struct nfc_digital_dev *ddev)
usb_kill_urb(dev->in_urb);
}

-static struct sk_buff *port100_alloc_skb(struct port100 *dev, unsigned int size)
+static struct sk_buff *port100_alloc_skb(const struct port100 *dev, unsigned int size)
{
struct sk_buff *skb;

@@ -1152,7 +1155,7 @@ static int port100_in_configure_hw(struct nfc_digital_dev *ddev, int type,
static void port100_in_comm_rf_complete(struct port100 *dev, void *arg,
struct sk_buff *resp)
{
- struct port100_cb_arg *cb_arg = arg;
+ const struct port100_cb_arg *cb_arg = arg;
nfc_digital_cmd_complete_t cb = cb_arg->complete_cb;
u32 status;
int rc;
@@ -1330,7 +1333,7 @@ static void port100_tg_comm_rf_complete(struct port100 *dev, void *arg,
struct sk_buff *resp)
{
u32 status;
- struct port100_cb_arg *cb_arg = arg;
+ const struct port100_cb_arg *cb_arg = arg;
nfc_digital_cmd_complete_t cb = cb_arg->complete_cb;
struct port100_tg_comm_rf_res *hdr;

@@ -1453,7 +1456,7 @@ static int port100_listen_mdaa(struct nfc_digital_dev *ddev,
static int port100_listen(struct nfc_digital_dev *ddev, u16 timeout,
nfc_digital_cmd_complete_t cb, void *arg)
{
- struct port100 *dev = nfc_digital_get_drvdata(ddev);
+ const struct port100 *dev = nfc_digital_get_drvdata(ddev);
struct sk_buff *skb;

skb = port100_alloc_skb(dev, 0);
--
2.27.0