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[PATCH v2 6/7] util/fifo8: Expose fifo8_pop_buf()
From: |
Philippe Mathieu-Daudé |
Subject: |
[PATCH v2 6/7] util/fifo8: Expose fifo8_pop_buf() |
Date: |
Mon, 22 Jul 2024 18:07:44 +0200 |
Extract fifo8_pop_buf() from hw/scsi/esp.c and expose
it as part of the <qemu/fifo8.h> API. This function takes
care of non-contiguous (wrapped) FIFO buffer (which is an
implementation detail).
Suggested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
include/qemu/fifo8.h | 14 ++++++++++++++
hw/scsi/esp.c | 36 +++---------------------------------
util/fifo8.c | 29 +++++++++++++++++++++++++++++
3 files changed, 46 insertions(+), 33 deletions(-)
diff --git a/include/qemu/fifo8.h b/include/qemu/fifo8.h
index 686918a3a4..21c7a22937 100644
--- a/include/qemu/fifo8.h
+++ b/include/qemu/fifo8.h
@@ -62,6 +62,20 @@ void fifo8_push_all(Fifo8 *fifo, const uint8_t *data,
uint32_t num);
*/
uint8_t fifo8_pop(Fifo8 *fifo);
+/**
+ * fifo8_pop_buf:
+ * @fifo: FIFO to pop from
+ * @dest: the buffer to write the data into (can be NULL)
+ * @destlen: size of @dest and maximum number of bytes to pop
+ *
+ * Pop a number of elements from the FIFO up to a maximum of @destlen.
+ * The popped data is copied into the @dest buffer.
+ * Care is taken when the data wraps around in the ring buffer.
+ *
+ * Returns: number of bytes popped.
+ */
+uint32_t fifo8_pop_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen);
+
/**
* fifo8_pop_constbuf:
* @fifo: FIFO to pop from
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 64384f9b0e..cec847b54a 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -197,39 +197,9 @@ static uint8_t esp_fifo_pop(ESPState *s)
return val;
}
-static uint32_t esp_fifo8_pop_buf(Fifo8 *fifo, uint8_t *dest, int maxlen)
-{
- const uint8_t *buf;
- uint32_t n, n2;
- int len;
-
- if (maxlen == 0) {
- return 0;
- }
-
- len = maxlen;
- buf = fifo8_pop_constbuf(fifo, len, &n);
- if (dest) {
- memcpy(dest, buf, n);
- }
-
- /* Add FIFO wraparound if needed */
- len -= n;
- len = MIN(len, fifo8_num_used(fifo));
- if (len) {
- buf = fifo8_pop_constbuf(fifo, len, &n2);
- if (dest) {
- memcpy(&dest[n], buf, n2);
- }
- n += n2;
- }
-
- return n;
-}
-
static uint32_t esp_fifo_pop_buf(ESPState *s, uint8_t *dest, int maxlen)
{
- uint32_t len = esp_fifo8_pop_buf(&s->fifo, dest, maxlen);
+ uint32_t len = fifo8_pop_buf(&s->fifo, dest, maxlen);
esp_update_drq(s);
return len;
@@ -335,7 +305,7 @@ static void do_command_phase(ESPState *s)
if (!cmdlen || !s->current_dev) {
return;
}
- esp_fifo8_pop_buf(&s->cmdfifo, buf, cmdlen);
+ fifo8_pop_buf(&s->cmdfifo, buf, cmdlen);
current_lun = scsi_device_find(&s->bus, 0, s->current_dev->id, s->lun);
if (!current_lun) {
@@ -381,7 +351,7 @@ static void do_message_phase(ESPState *s)
/* Ignore extended messages for now */
if (s->cmdfifo_cdb_offset) {
int len = MIN(s->cmdfifo_cdb_offset, fifo8_num_used(&s->cmdfifo));
- esp_fifo8_pop_buf(&s->cmdfifo, NULL, len);
+ fifo8_pop_buf(&s->cmdfifo, NULL, len);
s->cmdfifo_cdb_offset = 0;
}
}
diff --git a/util/fifo8.c b/util/fifo8.c
index 31f0d34c0c..6610b79182 100644
--- a/util/fifo8.c
+++ b/util/fifo8.c
@@ -102,6 +102,35 @@ const uint8_t *fifo8_pop_constbuf(Fifo8 *fifo, uint32_t
max, uint32_t *numptr)
return fifo8_peekpop_buf(fifo, max, numptr, true);
}
+uint32_t fifo8_pop_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen)
+{
+ const uint8_t *buf;
+ uint32_t n1, n2 = 0;
+ uint32_t len;
+
+ if (destlen == 0) {
+ return 0;
+ }
+
+ len = destlen;
+ buf = fifo8_pop_constbuf(fifo, len, &n1);
+ if (dest) {
+ memcpy(dest, buf, n1);
+ }
+
+ /* Add FIFO wraparound if needed */
+ len -= n1;
+ len = MIN(len, fifo8_num_used(fifo));
+ if (len) {
+ buf = fifo8_pop_constbuf(fifo, len, &n2);
+ if (dest) {
+ memcpy(&dest[n1], buf, n2);
+ }
+ }
+
+ return n1 + n2;
+}
+
bool fifo8_is_empty(Fifo8 *fifo)
{
return (fifo->num == 0);
--
2.41.0