hw/char/pl011: Improve RX flow tracing events

Log FIFO use (availability and depth).

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luc Michel <luc.michel@amd.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250220092903.3726-4-philmd@linaro.org>

hw/char/pl011.c

@@ -185,7 +185,7 @@ static void pl011_fifo_rx_put(void *opaque, uint32_t value)
     s->read_fifo[slot] = value;
     s->read_count++;
     s->flags &= ~PL011_FLAG_RXFE;
-    trace_pl011_fifo_rx_put(value, s->read_count);
+    trace_pl011_fifo_rx_put(value, s->read_count, pipe_depth);
     if (s->read_count == pipe_depth) {
         trace_pl011_fifo_rx_full();
         s->flags |= PL011_FLAG_RXFF;
@@ -248,12 +248,13 @@ static void pl011_write_txdata(PL011State *s, uint8_t data)
 static uint32_t pl011_read_rxdata(PL011State *s)
 {
     uint32_t c;
+    unsigned fifo_depth = pl011_get_fifo_depth(s);
 
     s->flags &= ~PL011_FLAG_RXFF;
     c = s->read_fifo[s->read_pos];
     if (s->read_count > 0) {
         s->read_count--;
-        s->read_pos = (s->read_pos + 1) & (pl011_get_fifo_depth(s) - 1);
+        s->read_pos = (s->read_pos + 1) & (fifo_depth - 1);
     }
     if (s->read_count == 0) {
         s->flags |= PL011_FLAG_RXFE;
@@ -261,7 +262,7 @@ static uint32_t pl011_read_rxdata(PL011State *s)
     if (s->read_count == s->read_trigger - 1) {
         s->int_level &= ~INT_RX;
     }
-    trace_pl011_read_fifo(s->read_count);
+    trace_pl011_read_fifo(s->read_count, fifo_depth);
     s->rsr = c >> 8;
     pl011_update(s);
     qemu_chr_fe_accept_input(&s->chr);
@@ -498,12 +499,13 @@ static int pl011_can_receive(void *opaque)
         qemu_log_mask(LOG_GUEST_ERROR,
                       "PL011 receiving data on disabled RX UART\n");
     }
-    trace_pl011_can_receive(s->lcr, s->read_count, r);
+    trace_pl011_can_receive(s->lcr, s->read_count, fifo_depth, fifo_available);
     return r;
 }
 
 static void pl011_receive(void *opaque, const uint8_t *buf, int size)
 {
+    trace_pl011_receive(size);
     /*
      * In loopback mode, the RX input signal is internally disconnected
      * from the entire receiving logics; thus, all inputs are ignored,

hw/char/trace-events

@@ -60,12 +60,13 @@ imx_serial_put_data(const char *chrname, uint32_t value) "%s: 0x%" PRIx32
 # pl011.c
 pl011_irq_state(int level) "irq state %d"
 pl011_read(uint32_t addr, uint32_t value, const char *regname) "addr 0x%03x value 0x%08x reg %s"
-pl011_read_fifo(int read_count) "FIFO read, read_count now %d"
+pl011_read_fifo(unsigned rx_fifo_used, size_t rx_fifo_depth) "RX FIFO read, used %u/%zu"
 pl011_write(uint32_t addr, uint32_t value, const char *regname) "addr 0x%03x value 0x%08x reg %s"
-pl011_can_receive(uint32_t lcr, int read_count, int r) "LCR 0x%08x read_count %d returning %d"
-pl011_fifo_rx_put(uint32_t c, int read_count) "new char 0x%02x read_count now %d"
+pl011_can_receive(uint32_t lcr, unsigned rx_fifo_used, size_t rx_fifo_depth, unsigned rx_fifo_available) "LCR 0x%02x, RX FIFO used %u/%zu, can_receive %u chars"
+pl011_fifo_rx_put(uint32_t c, unsigned read_count, size_t rx_fifo_depth) "RX FIFO push char [0x%02x] %d/%zu depth used"
 pl011_fifo_rx_full(void) "RX FIFO now full, RXFF set"
 pl011_baudrate_change(unsigned int baudrate, uint64_t clock, uint32_t ibrd, uint32_t fbrd) "new baudrate %u (clk: %" PRIu64 "hz, ibrd: %" PRIu32 ", fbrd: %" PRIu32 ")"
+pl011_receive(int size) "recv %d chars"
 
 # cmsdk-apb-uart.c
 cmsdk_apb_uart_read(uint64_t offset, uint64_t data, unsigned size) "CMSDK APB UART read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"