electronics/lw35-upgrade
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ioc: Implement printer buffer handling in kernel driver

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This commit is contained in:
Markus Koch 2020-01-03 16:45:28 +01:00
parent 7a7399a602
commit d588eeee42
1 changed files with 256 additions and 48 deletions
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304
ioc/kernel-driver/lw35ioc.c
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@ -11,6 +11,7 @@
#include <linux/uaccess.h> #include <linux/uaccess.h>
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/poll.h> #include <linux/poll.h>
#include <linux/circ_buf.h>
// #define ENABLE_DEBUG ENABLE_DEBUG // #define ENABLE_DEBUG ENABLE_DEBUG
@ -27,6 +28,11 @@ MODULE_PARM_DESC(debug_level, "Debug level");
static struct serdev_device *static_serdev = NULL; static struct serdev_device *static_serdev = NULL;
static DECLARE_WAIT_QUEUE_HEAD(wq); static DECLARE_WAIT_QUEUE_HEAD(wq);
void pbuf_work_handler(struct work_struct *work);
DECLARE_WORK(pbuf_work, pbuf_work_handler);
static DEFINE_SPINLOCK(printer_status_lock);
static struct of_device_id lw35ioc_dt_ids[] = { static struct of_device_id lw35ioc_dt_ids[] = {
{ .compatible = "brother,lw35", }, { .compatible = "brother,lw35", },
{ /* sentinel */ } { /* sentinel */ }
@ -37,7 +43,7 @@ MODULE_DEVICE_TABLE(of, lw35ioc_dt_ids);
#define DEVICE_NAME "lw35" #define DEVICE_NAME "lw35"
#define CLASS_NAME "lw35ioc" #define CLASS_NAME "lw35ioc"
/* Only used for initialization, not for actualy keycode mapping */ /* Only used for initialization, not for actual keycode mapping */
static int keycode_map[] = { static int keycode_map[] = {
KEY_A, KEY_B, KEY_C, KEY_D, KEY_E, KEY_F, KEY_G, KEY_H, KEY_I, KEY_J, KEY_A, KEY_B, KEY_C, KEY_D, KEY_E, KEY_F, KEY_G, KEY_H, KEY_I, KEY_J,
KEY_K, KEY_L, KEY_M, KEY_N, KEY_O, KEY_P, KEY_Q, KEY_R, KEY_S, KEY_T, KEY_K, KEY_L, KEY_M, KEY_N, KEY_O, KEY_P, KEY_Q, KEY_R, KEY_S, KEY_T,
@ -61,6 +67,7 @@ enum lw35ioc_packet_state {SYNC, TYPE, KEYBOARD, PRINTER};
struct lw35ioc_packet { struct lw35ioc_packet {
enum lw35ioc_packet_state state; enum lw35ioc_packet_state state;
int payload_offset;
}; };
struct lw35ioc_chardev { struct lw35ioc_chardev {
@ -70,7 +77,15 @@ struct lw35ioc_chardev {
int open_count; int open_count;
}; };
struct lw35ioc_printer_status{
int buffer_free;
int status;
int reserved0;
int reserved1;
};
#define UART_BUF_SIZE 256 #define UART_BUF_SIZE 256
#define PBUF_SIZE 256
struct lw35ioc_priv { struct lw35ioc_priv {
struct serdev_device *serdev; struct serdev_device *serdev;
@ -78,10 +93,17 @@ struct lw35ioc_priv {
struct gpio_desc *gpio_rst; /* GPIO to reset both AVRs */ struct gpio_desc *gpio_rst; /* GPIO to reset both AVRs */
struct lw35ioc_chardev chardev; struct lw35ioc_chardev chardev;
struct lw35ioc_printer_status printer_status_temp;
struct lw35ioc_printer_status printer_status;
char uart_buf_rx[UART_BUF_SIZE]; char uart_buf_rx[UART_BUF_SIZE];
char *uart_buf_rx_rd; char *uart_buf_rx_rd;
char *uart_buf_rx_wr; char *uart_buf_rx_wr;
char pbuf[PBUF_SIZE];
unsigned long pbuf_tail;
unsigned long pbuf_head;
enum lw35ioc_state state; enum lw35ioc_state state;
struct lw35ioc_packet packet; struct lw35ioc_packet packet;
}; };
@ -95,6 +117,7 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
unsigned char c; unsigned char c;
int ev; int ev;
int i; int i;
unsigned long lock_flags;
#ifdef ENABLE_DEBUG #ifdef ENABLE_DEBUG
dev_info(&serdev->dev, "IRQ.\n"); dev_info(&serdev->dev, "IRQ.\n");
@ -109,6 +132,7 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
if (c == 0xFF) if (c == 0xFF)
priv->packet.state = TYPE; priv->packet.state = TYPE;
break; break;
case TYPE: case TYPE:
if (c == 0x55) if (c == 0x55)
priv->packet.state = KEYBOARD; priv->packet.state = KEYBOARD;
@ -116,7 +140,9 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
priv->packet.state = PRINTER; priv->packet.state = PRINTER;
else else
priv->packet.state = SYNC; priv->packet.state = SYNC;
priv->packet.payload_offset = 0;
break; break;
case KEYBOARD: case KEYBOARD:
if (c > 127) { if (c > 127) {
c -= 128; c -= 128;
@ -128,9 +154,46 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
input_sync(priv->input_dev); input_sync(priv->input_dev);
priv->packet.state = SYNC; priv->packet.state = SYNC;
break; break;
case PRINTER: case PRINTER:
dev_info(&serdev->dev, "Printer not yet implemented.\n"); switch (priv->packet.payload_offset) {
priv->packet.state = SYNC; case 0: /* Status */
priv->printer_status_temp.status = (int)c;
break;
case 1: /* Buffer status */
priv->printer_status_temp.buffer_free = (int)c;
break;
case 2: /* Reserved */
priv->printer_status_temp.reserved0 = (int)c;
break;
case 3: /* Reserved */
priv->printer_status_temp.reserved1 = (int)c;
dev_info(&serdev->dev,
"New printer status. status=0x%02X buffer_free=0x%02X [0x%02X,0x%02X].\n",
priv->printer_status_temp.status,
priv->printer_status_temp.buffer_free,
priv->printer_status_temp.reserved0,
priv->printer_status_temp.reserved1);
if (priv->printer_status_temp.status == 0xFF) {
dev_err(&serdev->dev,
"HARDFAULT in printer firmware! Reset required.\n");
}
spin_lock_irqsave(&printer_status_lock, lock_flags);
memcpy(&priv->printer_status,
&priv->printer_status_temp,
sizeof(priv->printer_status));
spin_unlock_irqrestore(&printer_status_lock, lock_flags);
if (priv->printer_status_temp.buffer_free > 0)
schedule_work(&pbuf_work);
priv->packet.state = SYNC;
break;
default:
break;
}
priv->packet.payload_offset++;
break; break;
} }
} }
@ -145,25 +208,31 @@ static int lw35ioc_receive_buf(struct serdev_device *serdev,
struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev); struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
int i; int i;
if (priv->state == ACTIVE) switch (priv->state) {
case ACTIVE:
return lw35ioc_process_buf(serdev, data, count); return lw35ioc_process_buf(serdev, data, count);
break;
for (i = 0; i < count; ++i) { case PASSIVE:
break;
default:
/* Pass data directly to chardev */
for (i = 0; i < count; ++i) {
#ifdef ENABLE_DEBUG #ifdef ENABLE_DEBUG
dev_info(&serdev->dev, " RX [PSV]: %02x\n", data[i]); dev_info(&serdev->dev, " RX [PSV]: %02x\n", data[i]);
#endif #endif
*(priv->uart_buf_rx_wr) = data[i]; *(priv->uart_buf_rx_wr) = data[i];
if (priv->uart_buf_rx_wr == priv->uart_buf_rx + UART_BUF_SIZE - 1) if (priv->uart_buf_rx_wr == priv->uart_buf_rx + UART_BUF_SIZE - 1)
priv->uart_buf_rx_wr = priv->uart_buf_rx; priv->uart_buf_rx_wr = priv->uart_buf_rx;
else else
priv->uart_buf_rx_wr++; priv->uart_buf_rx_wr++;
if (priv->uart_buf_rx_rd == priv->uart_buf_rx_wr) { if (priv->uart_buf_rx_rd == priv->uart_buf_rx_wr) {
dev_err(&serdev->dev, "UART RX buffer overflow.\n"); dev_err(&serdev->dev, "UART RX buffer overflow.\n");
}
} }
}
wake_up_interruptible(&wq); wake_up_interruptible(&wq);
}
return count; /* Pretend we read all data */ return count; /* Pretend we read all data */
} }
@ -205,32 +274,38 @@ static int lw35ioc_chardev_open(struct inode *inodep, struct file *filep) {
if (!priv->chardev.open_count) { if (!priv->chardev.open_count) {
dev_info(&serdev->dev, "Opened chardev.\n"); dev_info(&serdev->dev, "Opened chardev.\n");
if (priv->state != ACTIVE && switch (priv->state) {
priv->state != PASSIVE) { case PROG_KBD:
lw35ioc_reset_ioc_hw(serdev); lw35ioc_reset_ioc_hw(serdev);
serdev_device_write(serdev, "X", 1, 0);
switch (priv->state) { dev_info(&serdev->dev, "Put ioc into programming mode: keyboard.\n");
case PROG_KBD: break;
serdev_device_write(serdev, "X", 1, 0); case PROG_PRI:
dev_info(&serdev->dev, "Put ioc into programming mode: keyboard.\n"); lw35ioc_reset_ioc_hw(serdev);
break; serdev_device_write(serdev, "Y", 1, 0);
case PROG_PRI: dev_info(&serdev->dev, "Put ioc into programming mode: printer.\n");
serdev_device_write(serdev, "Y", 1, 0); break;
dev_info(&serdev->dev, "Put ioc into programming mode: printer.\n"); case BYPASS:
break; lw35ioc_reset_ioc_hw(serdev);
case BYPASS: serdev_device_write(serdev, "XX", 2, 0);
serdev_device_write(serdev, "XX", 2, 0); dev_info(&serdev->dev, "Put ioc into bypass mode.\n");
dev_info(&serdev->dev, "Put ioc into bypass mode.\n"); break;
break; case PASSIVE:
default: lw35ioc_reset_ioc_hw(serdev);
/* For other modes, we just wait for the reset to be over */ usleep_range(1000000, 1010000);
usleep_range(1000000, 1010000); dev_info(&serdev->dev, "Put ioc into active mode.\n");
break; priv->state = ACTIVE;
} break;
case ACTIVE:
/* Don't do anything when active */
break;
default:
break;
} }
} else { } else {
dev_err(&serdev->dev, "Rejected. Device may only be opened once.\n"); dev_err(&serdev->dev, "Rejected. Device may only be opened once.\n");
//return -EBUSY; //return -EBUSY; // TODO
} }
priv->chardev.open_count++; priv->chardev.open_count++;
@ -251,7 +326,7 @@ static ssize_t lw35ioc_chardev_read(struct file *filep, char *buffer, size_t len
wait_event_interruptible(wq, priv->uart_buf_rx_rd != priv->uart_buf_rx_wr); wait_event_interruptible(wq, priv->uart_buf_rx_rd != priv->uart_buf_rx_wr);
available = priv->uart_buf_rx_wr - priv->uart_buf_rx_rd; available = priv->uart_buf_rx_wr - priv->uart_buf_rx_rd;
if (available < 0) if (available < 0)
available = 1; available = 1; /* TODO: We should calculate the remaining block until wraparound here... */
if (!available) if (!available)
return -EAGAIN; return -EAGAIN;
} }
@ -279,12 +354,61 @@ char msg[256]; // TODO
static ssize_t lw35ioc_chardev_write(struct file *filep, const char *buffer, size_t len, loff_t *offset) { static ssize_t lw35ioc_chardev_write(struct file *filep, const char *buffer, size_t len, loff_t *offset) {
struct serdev_device *serdev = filep->private_data; struct serdev_device *serdev = filep->private_data;
struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev); struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
unsigned long tail;
int i;
int ret;
if (len > 256) { switch (priv->state) {
len = 256; case ACTIVE:
/* Put data into pbuf */
// TODO: spinlock
if (CIRC_SPACE(priv->pbuf_head, READ_ONCE(priv->pbuf_tail), PBUF_SIZE) < 1) {
dev_err(&serdev->dev, "chdev write: Waiting for space...\n");
if (ret = (wait_event_interruptible(wq, CIRC_SPACE(priv->pbuf_head, priv->pbuf_tail, PBUF_SIZE) >= 1))) { // TODO: Accessing pbuf_tail without any protection... this might be bad?
dev_err(&serdev->dev,
"chdev write: device closed while waiting. ret: %d\n",
ret);
// TODO: This is not proper handling of this I guess...
return len;
}
dev_err(&serdev->dev, "chdev write: done waiting...\n");
}
tail = READ_ONCE(priv->pbuf_tail);
for (i = 0; i < len; ++i) { // TODO: Block copy would be faster...
if (CIRC_SPACE(priv->pbuf_head, tail, PBUF_SIZE) >= 1) {
ret = copy_from_user(priv->pbuf + priv->pbuf_head,
buffer + i,
1);
if (ret) {
dev_err(&serdev->dev, "chdev write: copy_from_user failed (%d).\n",
ret);
i = len - 1;
}
smp_store_release(&(priv->pbuf_head),
(priv->pbuf_head + 1) & (PBUF_SIZE - 1));
} else {
dev_warn(&serdev->dev, "chdev write: ring buffer full.\n");
break;
}
}
len = i;
schedule_work(&pbuf_work);
dev_info(&serdev->dev,
"Copied %d bytes to FIFO (FIFO free: %d)",
len, CIRC_SPACE(priv->pbuf_head, tail, PBUF_SIZE));
break;
case PASSIVE:
len = -EBUSY; // TODO: Can I do this?
break;
default: /* Pass-through */
if (len > 256) {
len = 256;
}
copy_from_user(msg, buffer, len); // TODO: Return value
serdev_device_write_buf(serdev, msg, len);
} }
copy_from_user(msg, buffer, len);
serdev_device_write_buf(serdev, msg, len);
return len; return len;
} }
@ -337,6 +461,75 @@ __poll_t poll(struct file *filep, struct poll_table_struct *ptab)
return 0; return 0;
} }
#define PRINTER_READY_MASK (0b00011111)
int printer_ready_for_data(struct lw35ioc_printer_status printer_status)
{
return ((printer_status.status & PRINTER_READY_MASK) == PRINTER_READY_MASK);
}
void pbuf_work_handler(struct work_struct *work)
{
// TODO: get private data using container_of(): https://linux-kernel-labs.github.io/master/labs/deferred_work.html
struct serdev_device *serdev = static_serdev; // Not cool, but whatever...
struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
unsigned long head;
unsigned long tail;
unsigned long lock_flags;
int bsize = 0;
int i;
int locked = 0;
dev_info(&serdev->dev,
"pbuf_work_handler\n");
while (1) {
// TODO: We are the only consumer, so we should be fine without a spinlock, right?
head = smp_load_acquire(&priv->pbuf_head);
tail = priv->pbuf_tail;
bsize = CIRC_CNT(head, tail, PBUF_SIZE);
dev_info(&serdev->dev, "CIRC CNT=%d\n", bsize);
if (bsize == 0)
break;
spin_lock_irqsave(&printer_status_lock, lock_flags);
locked = 1;
if (!printer_ready_for_data(priv->printer_status)) {
dev_warn(&serdev->dev, "Cannot transmit data to device. Device is not ready.\n");
break;
}
if (bsize > priv->printer_status.buffer_free)
bsize = priv->printer_status.buffer_free;
if (bsize > CIRC_CNT_TO_END(head, tail, PBUF_SIZE))
bsize = CIRC_CNT_TO_END(head, tail, PBUF_SIZE);
if (bsize > priv->printer_status.buffer_free - 20)
bsize = priv->printer_status.buffer_free - 20; // TODO: Bug workaround
dev_info(&serdev->dev, "TX %d of %d bytes [%d bytes free on device].\n",
bsize,
CIRC_CNT(head, tail, PBUF_SIZE),
priv->printer_status.buffer_free);
priv->printer_status.buffer_free-=bsize;
spin_unlock_irqrestore(&printer_status_lock, lock_flags);
locked = 0;
if (bsize == 0) {
dev_warn(&serdev->dev, "Cannot transmit data to device. Device buffer is full.\n");
break;
}
serdev_device_write_buf(serdev,
priv->pbuf + tail,
bsize);
for (i=0; i<bsize; ++i) {
dev_info(&serdev->dev,
"UART TX: %c\n",
priv->pbuf[tail + i]);
}
smp_store_release(&priv->pbuf_tail,
(tail + bsize) & (PBUF_SIZE - 1));
}
if (locked)
spin_unlock_irqrestore(&printer_status_lock, lock_flags);
wake_up_interruptible(&wq); // There's some space available in the FIFO now, so wake up chardev write
}
static struct file_operations fops = static struct file_operations fops =
@ -382,7 +575,7 @@ static int lw35ioc_cdev_init(struct serdev_device *serdev)
return PTR_ERR(priv->chardev.device); return PTR_ERR(priv->chardev.device);
} }
dev_err(&serdev->dev, "Device class created correctly\n"); dev_info(&serdev->dev, "Device class created correctly\n");
return 0; return 0;
} }
@ -414,11 +607,16 @@ static int lw35ioc_probe(struct serdev_device *serdev)
priv->uart_buf_rx_rd = priv->uart_buf_rx; priv->uart_buf_rx_rd = priv->uart_buf_rx;
priv->uart_buf_rx_wr = priv->uart_buf_rx; priv->uart_buf_rx_wr = priv->uart_buf_rx;
priv->pbuf_tail = 0;
priv->pbuf_head = 0;
priv->printer_status.buffer_free = 0;
priv->printer_status.status = 0;
priv->serdev = serdev; priv->serdev = serdev;
static_serdev = serdev; static_serdev = serdev;
priv->packet.state = SYNC; priv->packet.state = SYNC;
serdev_device_set_drvdata(serdev, priv); serdev_device_set_drvdata(serdev, priv);
serdev_device_set_client_ops(serdev, &lw35ioc_serdev_ops);
/* Register input device */ /* Register input device */
input_dev = devm_input_allocate_device(&serdev->dev); input_dev = devm_input_allocate_device(&serdev->dev);
@ -440,12 +638,13 @@ static int lw35ioc_probe(struct serdev_device *serdev)
goto fail_input; goto fail_input;
} }
serdev_device_set_client_ops(serdev, &lw35ioc_serdev_ops);
ret = serdev_device_open(serdev); ret = serdev_device_open(serdev);
if (ret) { if (ret) {
dev_err(&serdev->dev, "Unable to open device.\n"); dev_err(&serdev->dev, "Unable to open device.\n");
goto fail_serdev; goto fail_serdev;
} }
speed = serdev_device_set_baudrate(serdev, speed); speed = serdev_device_set_baudrate(serdev, speed);
dev_info(&serdev->dev, "Using baudrate: %u\n", speed); dev_info(&serdev->dev, "Using baudrate: %u\n", speed);
@ -486,17 +685,26 @@ static void lw35ioc_remove(struct serdev_device *serdev)
{ {
struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev); struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
dev_info(&serdev->dev, "remove\n");
dev_info(&serdev->dev, " cdev class: %p\n", priv->chardev.class);
device_destroy(priv->chardev.class, MKDEV(priv->chardev.major_number, 0)); device_destroy(priv->chardev.class, MKDEV(priv->chardev.major_number, 0));
dev_info(&serdev->dev, "unreg\n");
class_unregister(priv->chardev.class); class_unregister(priv->chardev.class);
class_destroy(priv->chardev.class); dev_info(&serdev->dev, "destroy: SKIP\n");
//class_destroy(priv->chardev.class);
dev_info(&serdev->dev, "unreg-dev\n");
unregister_chrdev(priv->chardev.major_number, DEVICE_NAME); unregister_chrdev(priv->chardev.major_number, DEVICE_NAME);
dev_info(&serdev->dev, " gpio rst: %p\n", priv->gpio_rst);
dev_info(&serdev->dev, " serdev: %p\n", priv->serdev);
dev_info(&serdev->dev, " input dev: %p\n", priv->input_dev);
lw35ioc_set_hw_reset(serdev, 1); lw35ioc_set_hw_reset(serdev, 1);
gpiod_put(priv->gpio_rst); gpiod_put(priv->gpio_rst);
serdev_device_close(priv->serdev); serdev_device_close(priv->serdev);
input_unregister_device(priv->input_dev); input_unregister_device(priv->input_dev);
dev_info(&serdev->dev, "remove\n"); dev_info(&serdev->dev, "done.\n");
return; return;
} }