| Message ID | 20250220092903.3726-5-philmd@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | hw/char: Improve RX FIFO depth uses | expand |
On 2/20/25 01:28, Philippe Mathieu-Daudé wrote: > While we model a 16-elements RX FIFO since the PL011 model was > introduced in commit cdbdb648b7c ("ARM Versatile Platform Baseboard > emulation"), we only read 1 char at a time! > > Have the IOCanReadHandler handler return how many elements are > available, and use that in the IOReadHandler handler. > > Example of FIFO better used by enabling the pl011 tracing events > and running the tests/functional/test_aarch64_virt.py tests: > > pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars > pl011_receive recv 5 chars > pl011_fifo_rx_put RX FIFO push char [0x72] 1/16 depth used > pl011_irq_state irq state 1 > pl011_fifo_rx_put RX FIFO push char [0x6f] 2/16 depth used > pl011_fifo_rx_put RX FIFO push char [0x6f] 3/16 depth used > pl011_fifo_rx_put RX FIFO push char [0x74] 4/16 depth used > pl011_fifo_rx_put RX FIFO push char [0x0d] 5/16 depth used > pl011_can_receive LCR 0x70, RX FIFO used 5/16, can_receive 11 chars > pl011_can_receive LCR 0x70, RX FIFO used 5/16, can_receive 11 chars > pl011_write addr 0x038 value 0x00000050 reg IMSC > pl011_irq_state irq state 1 > pl011_can_receive LCR 0x70, RX FIFO used 5/16, can_receive 11 chars > pl011_read addr 0x03c value 0x00000030 reg RIS > pl011_write addr 0x044 value 0x00000000 reg ICR > pl011_irq_state irq state 1 > pl011_read addr 0x018 value 0x00000080 reg FR > pl011_read_fifo RX FIFO read, used 4/16 > pl011_irq_state irq state 1 > pl011_read addr 0x000 value 0x00000072 reg DR > pl011_can_receive LCR 0x70, RX FIFO used 4/16, can_receive 12 chars > pl011_read addr 0x018 value 0x00000080 reg FR > pl011_read_fifo RX FIFO read, used 3/16 > pl011_irq_state irq state 1 > pl011_read addr 0x000 value 0x0000006f reg DR > pl011_can_receive LCR 0x70, RX FIFO used 3/16, can_receive 13 chars > pl011_read addr 0x018 value 0x00000080 reg FR > pl011_read_fifo RX FIFO read, used 2/16 > pl011_irq_state irq state 1 > pl011_read addr 0x000 value 0x0000006f reg DR > pl011_can_receive LCR 0x70, RX FIFO used 2/16, can_receive 14 chars > pl011_read addr 0x018 value 0x00000080 reg FR > pl011_read_fifo RX FIFO read, used 1/16 > pl011_irq_state irq state 1 > pl011_read addr 0x000 value 0x00000074 reg DR > pl011_can_receive LCR 0x70, RX FIFO used 1/16, can_receive 15 chars > pl011_read addr 0x018 value 0x00000080 reg FR > pl011_read_fifo RX FIFO read, used 0/16 > pl011_irq_state irq state 0 > pl011_read addr 0x000 value 0x0000000d reg DR > pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars > pl011_read addr 0x018 value 0x00000090 reg FR > pl011_read addr 0x03c value 0x00000020 reg RIS > pl011_write addr 0x038 value 0x00000050 reg IMSC > pl011_irq_state irq state 0 > pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars > pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars > pl011_read addr 0x018 value 0x00000090 reg FR > pl011_write addr 0x000 value 0x00000072 reg DR > > Inspired-by: Peter Maydell <peter.maydell@linaro.org> > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> > Reviewed-by: Luc Michel <luc.michel@amd.com> > --- > hw/char/pl011.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/hw/char/pl011.c b/hw/char/pl011.c > index f7485e7c541..23a9db8c57c 100644 > --- a/hw/char/pl011.c > +++ b/hw/char/pl011.c > @@ -489,7 +489,6 @@ static int pl011_can_receive(void *opaque) > PL011State *s = (PL011State *)opaque; > unsigned fifo_depth = pl011_get_fifo_depth(s); > unsigned fifo_available = fifo_depth - s->read_count; > - int r = fifo_available ? 1 : 0; > > if (!(s->cr & CR_UARTEN)) { > qemu_log_mask(LOG_GUEST_ERROR, > @@ -500,7 +499,8 @@ static int pl011_can_receive(void *opaque) > "PL011 receiving data on disabled RX UART\n"); > } > trace_pl011_can_receive(s->lcr, s->read_count, fifo_depth, fifo_available); > - return r; > + > + return fifo_available; > } Ah, I get it; my bool comment was ill-informed. > static void pl011_receive(void *opaque, const uint8_t *buf, int size) > @@ -515,7 +515,9 @@ static void pl011_receive(void *opaque, const uint8_t *buf, int size) > return; > } > > - pl011_fifo_rx_put(opaque, *buf); > + for (int i = 0; i < size; i++) { > + pl011_fifo_rx_put(opaque, buf[i]); > + } > } Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
diff --git a/hw/char/pl011.c b/hw/char/pl011.c index f7485e7c541..23a9db8c57c 100644 --- a/hw/char/pl011.c +++ b/hw/char/pl011.c @@ -489,7 +489,6 @@ static int pl011_can_receive(void *opaque) PL011State *s = (PL011State *)opaque; unsigned fifo_depth = pl011_get_fifo_depth(s); unsigned fifo_available = fifo_depth - s->read_count; - int r = fifo_available ? 1 : 0; if (!(s->cr & CR_UARTEN)) { qemu_log_mask(LOG_GUEST_ERROR, @@ -500,7 +499,8 @@ static int pl011_can_receive(void *opaque) "PL011 receiving data on disabled RX UART\n"); } trace_pl011_can_receive(s->lcr, s->read_count, fifo_depth, fifo_available); - return r; + + return fifo_available; } static void pl011_receive(void *opaque, const uint8_t *buf, int size) @@ -515,7 +515,9 @@ static void pl011_receive(void *opaque, const uint8_t *buf, int size) return; } - pl011_fifo_rx_put(opaque, *buf); + for (int i = 0; i < size; i++) { + pl011_fifo_rx_put(opaque, buf[i]); + } } static void pl011_event(void *opaque, QEMUChrEvent event)
While we model a 16-elements RX FIFO since the PL011 model was introduced in commit cdbdb648b7c ("ARM Versatile Platform Baseboard emulation"), we only read 1 char at a time! Have the IOCanReadHandler handler return how many elements are available, and use that in the IOReadHandler handler. Example of FIFO better used by enabling the pl011 tracing events and running the tests/functional/test_aarch64_virt.py tests: pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars pl011_receive recv 5 chars pl011_fifo_rx_put RX FIFO push char [0x72] 1/16 depth used pl011_irq_state irq state 1 pl011_fifo_rx_put RX FIFO push char [0x6f] 2/16 depth used pl011_fifo_rx_put RX FIFO push char [0x6f] 3/16 depth used pl011_fifo_rx_put RX FIFO push char [0x74] 4/16 depth used pl011_fifo_rx_put RX FIFO push char [0x0d] 5/16 depth used pl011_can_receive LCR 0x70, RX FIFO used 5/16, can_receive 11 chars pl011_can_receive LCR 0x70, RX FIFO used 5/16, can_receive 11 chars pl011_write addr 0x038 value 0x00000050 reg IMSC pl011_irq_state irq state 1 pl011_can_receive LCR 0x70, RX FIFO used 5/16, can_receive 11 chars pl011_read addr 0x03c value 0x00000030 reg RIS pl011_write addr 0x044 value 0x00000000 reg ICR pl011_irq_state irq state 1 pl011_read addr 0x018 value 0x00000080 reg FR pl011_read_fifo RX FIFO read, used 4/16 pl011_irq_state irq state 1 pl011_read addr 0x000 value 0x00000072 reg DR pl011_can_receive LCR 0x70, RX FIFO used 4/16, can_receive 12 chars pl011_read addr 0x018 value 0x00000080 reg FR pl011_read_fifo RX FIFO read, used 3/16 pl011_irq_state irq state 1 pl011_read addr 0x000 value 0x0000006f reg DR pl011_can_receive LCR 0x70, RX FIFO used 3/16, can_receive 13 chars pl011_read addr 0x018 value 0x00000080 reg FR pl011_read_fifo RX FIFO read, used 2/16 pl011_irq_state irq state 1 pl011_read addr 0x000 value 0x0000006f reg DR pl011_can_receive LCR 0x70, RX FIFO used 2/16, can_receive 14 chars pl011_read addr 0x018 value 0x00000080 reg FR pl011_read_fifo RX FIFO read, used 1/16 pl011_irq_state irq state 1 pl011_read addr 0x000 value 0x00000074 reg DR pl011_can_receive LCR 0x70, RX FIFO used 1/16, can_receive 15 chars pl011_read addr 0x018 value 0x00000080 reg FR pl011_read_fifo RX FIFO read, used 0/16 pl011_irq_state irq state 0 pl011_read addr 0x000 value 0x0000000d reg DR pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars pl011_read addr 0x018 value 0x00000090 reg FR pl011_read addr 0x03c value 0x00000020 reg RIS pl011_write addr 0x038 value 0x00000050 reg IMSC pl011_irq_state irq state 0 pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars pl011_can_receive LCR 0x70, RX FIFO used 0/16, can_receive 16 chars pl011_read addr 0x018 value 0x00000090 reg FR pl011_write addr 0x000 value 0x00000072 reg DR Inspired-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Luc Michel <luc.michel@amd.com> --- hw/char/pl011.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)