Changes in uspace/lib/c/generic/io/chardev.c [19ea61d:75751db6] in mainline

File:

• uspace/lib/c/generic/io/chardev.c (modified) (2 diffs)

uspace/lib/c/generic/io/chardev.c

@@ -1 +1 @@
 /*
  * Copyright (c) 2011 Jan Vesely
- * Copyright (c) 2017 Jiri Svoboda
  * All rights reserved.
  *
@@ -28 +27 @@
  */
 
-/** @addtogroup libc
- * @{
- */
-/**
- * @file
- * @brief Character device client interface
- */
-
 #include <errno.h>
 #include <mem.h>
 #include <io/chardev.h>
 #include <ipc/chardev.h>
-#include <stddef.h>
-#include <stdlib.h>
 
-/** Open character device.
- *
- * @param sess Session with the character device
- * @param rchardev Place to store pointer to the new character device structure
- *
- * @return EOK on success, ENOMEM if out of memory, EIO on I/O error
- */
-int chardev_open(async_sess_t *sess, chardev_t **rchardev)
+ssize_t chardev_read(async_exch_t *exch, void *data, size_t size)
 {
-        chardev_t *chardev;
+        if (!exch)
+                return EBADMEM;
+        if (size > 4 * sizeof(sysarg_t))
+                return ELIMIT;
 
-        chardev = calloc(1, sizeof(chardev_t));
-        if (chardev == NULL)
-                return ENOMEM;
-
-        chardev->sess = sess;
-        *rchardev = chardev;
-
-        /* EIO might be used in a future implementation */
-        return EOK;
+        sysarg_t message[4] = { 0 };
+        const ssize_t ret = async_req_1_4(exch, CHARDEV_READ, size,
+            &message[0], &message[1], &message[2], &message[3]);
+        if (ret > 0 && (size_t)ret <= size)
+                memcpy(data, message, size);
+        return ret;
 }
 
-/** Close character device.
- *
- * Frees the character device structure. The underlying session is
- * not affected.
- *
- * @param chardev Character device or @c NULL
- */
-void chardev_close(chardev_t *chardev)
+ssize_t chardev_write(async_exch_t *exch, const void *data, size_t size)
 {
-        free(chardev);
+        if (!exch)
+                return EBADMEM;
+        if (size > 3 * sizeof(sysarg_t))
+                return ELIMIT;
+
+        sysarg_t message[3] = { 0 };
+        memcpy(message, data, size);
+        return async_req_4_0(exch, CHARDEV_WRITE, size,
+            message[0], message[1], message[2]);
 }
-
-/** Read from character device.
- *
- * Read as much data as is available from character device up to @a size
- * bytes into @a buf. On success EOK is returned and at least one byte
- * is read (if no byte is available the function blocks). The number
- * of bytes read is stored in @a *nread.
- *
- * On error a non-zero error code is returned and @a *nread is filled with
- * the number of bytes that were successfully transferred.
- *
- * @param chardev Character device
- * @param buf Destination buffer
- * @param size Maximum number of bytes to read
- * @param nread Place to store actual number of bytes read
- *
- * @return EOK on success or non-zero error code
- */
-int chardev_read(chardev_t *chardev, void *buf, size_t size, size_t *nread)
-{
-        async_exch_t *exch = async_exchange_begin(chardev->sess);
-
-        if (size > DATA_XFER_LIMIT) {
-                /* This should not hurt anything. */
-                size = DATA_XFER_LIMIT;
-        }
-
-        ipc_call_t answer;
-        aid_t req = async_send_0(exch, CHARDEV_READ, &answer);
-        int rc = async_data_read_start(exch, buf, size);
-        async_exchange_end(exch);
-
-        if (rc != EOK) {
-                async_forget(req);
-                *nread = 0;
-                return rc;
-        }
-
-        sysarg_t retval;
-        async_wait_for(req, &retval);
-
-        if (retval != EOK) {
-                *nread = 0;
-                return retval;
-        }
-
-        *nread = IPC_GET_ARG2(answer);
-        /* In case of partial success, ARG1 contains the error code */
-        return IPC_GET_ARG1(answer);
-
-}
-
-/** Write up to DATA_XFER_LIMIT bytes to character device.
- *
- * Write up to @a size or DATA_XFER_LIMIT bytes from @a data to character
- * device. On success EOK is returned, bytes were written and @a *nwritten
- * is set to min(@a size, DATA_XFER_LIMIT)
- *
- * On error a non-zero error code is returned and @a *nwritten is filled with
- * the number of bytes that were successfully transferred.
- *
- * @param chardev Character device
- * @param buf Destination buffer
- * @param size Maximum number of bytes to read
- * @param nwritten Place to store actual number of bytes written
- *
- * @return EOK on success or non-zero error code
- */
-static int chardev_write_once(chardev_t *chardev, const void *data,
-    size_t size, size_t *nwritten)
-{
-        async_exch_t *exch = async_exchange_begin(chardev->sess);
-        ipc_call_t answer;
-        aid_t req;
-        int rc;
-
-        /* Break down large transfers */
-        if (size > DATA_XFER_LIMIT)
-                size = DATA_XFER_LIMIT;
-
-        req = async_send_0(exch, CHARDEV_WRITE, &answer);
-        rc = async_data_write_start(exch, data, size);
-        async_exchange_end(exch);
-
-        if (rc != EOK) {
-                async_forget(req);
-                *nwritten = 0;
-                return rc;
-        }
-
-        sysarg_t retval;
-        async_wait_for(req, &retval);
-        if (retval != EOK) {
-                *nwritten = 0;
-                return retval;
-        }
-
-        *nwritten = IPC_GET_ARG2(answer);
-        /* In case of partial success, ARG1 contains the error code */
-        return IPC_GET_ARG1(answer);
-}
-
-/** Write to character device.
- *
- * Write @a size bytes from @a data to character device. On success EOK
- * is returned, all bytes were written and @a *nwritten is set to @a size.
- *
- * On error a non-zero error code is returned and @a *nwritten is filled with
- * the number of bytes that were successfully transferred.
- *
- * @param chardev Character device
- * @param buf Destination buffer
- * @param size Maximum number of bytes to read
- * @param nwritten Place to store actual number of bytes written
- *
- * @return EOK on success or non-zero error code
- */
-int chardev_write(chardev_t *chardev, const void *data, size_t size,
-    size_t *nwritten)
-{
-        size_t nw;
-        size_t p;
-        int rc;
-
-        p = 0;
-        while (p < size) {
-                rc = chardev_write_once(chardev, data + p, size - p, &nw);
-                /* nw is always valid, we can have partial success */
-                p += nw;
-
-                if (rc != EOK) {
-                        /* We can return partial success */
-                        *nwritten = p;
-                        return rc;
-                }
-        }
-
-        *nwritten = p;
-        return EOK;
-}
-
-/** @}
- */