On Mon, Jan 30, 2012 at 09:22, Fabien Chouteau <chout...@adacore.com> wrote:
> On 28/01/2012 13:20, Blue Swirl wrote:
>> On Thu, Jan 26, 2012 at 17:03, Fabien Chouteau <chout...@adacore.com> wrote:
>>> This patch implements the RX channel of GRLIB UART with a FIFO to
>>> improve data rate.
>>>
>>> Signed-off-by: Fabien Chouteau <chout...@adacore.com>
>>> ---
>>> hw/grlib_apbuart.c | 106
>>> +++++++++++++++++++++++++++++++++++++++++++--------
>>> trace-events | 1 +
>>> 2 files changed, 90 insertions(+), 17 deletions(-)
>>>
>>> diff --git a/hw/grlib_apbuart.c b/hw/grlib_apbuart.c
>>> index f8a64e1..51406c6 100644
>>> --- a/hw/grlib_apbuart.c
>>> +++ b/hw/grlib_apbuart.c
>>> @@ -24,7 +24,6 @@
>>>
>>> #include "sysbus.h"
>>> #include "qemu-char.h"
>>> -#include "ptimer.h"
>>>
>>> #include "trace.h"
>>>
>>> @@ -66,6 +65,8 @@
>>> #define SCALER_OFFSET 0x0C /* not supported */
>>> #define FIFO_DEBUG_OFFSET 0x10 /* not supported */
>>>
>>> +#define FIFO_LENGTH 1024
>>> +
>>> typedef struct UART {
>>> SysBusDevice busdev;
>>> MemoryRegion iomem;
>>> @@ -77,21 +78,67 @@ typedef struct UART {
>>> uint32_t receive;
>>> uint32_t status;
>>> uint32_t control;
>>> +
>>> + /* FIFO */
>>> + char buffer[FIFO_LENGTH];
>>> + int len;
>>> + int current;
>>> } UART;
>>>
>>> +static int uart_data_to_read(UART *uart)
>>> +{
>>> + return uart->current < uart->len;
>>> +}
>>> +
>>> +static char uart_pop(UART *uart)
>>> +{
>>> + char ret;
>>> +
>>> + if (uart->len == 0) {
>>> + uart->status &= ~UART_DATA_READY;
>>> + return 0;
>>> + }
>>> +
>>> + ret = uart->buffer[uart->current++];
>>> +
>>> + if (uart->current >= uart->len) {
>>> + /* Flush */
>>> + uart->len = 0;
>>> + uart->current = 0;
>>> + }
>>> +
>>> + if (!uart_data_to_read(uart)) {
>>> + uart->status &= ~UART_DATA_READY;
>>> + }
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static void uart_add_to_fifo(UART *uart,
>>> + const uint8_t *buffer,
>>> + int length)
>>> +{
>>> + if (uart->len + length > FIFO_LENGTH) {
>>> + abort();
>>
>> A guest could trigger this abort(), which is not OK. I think you can
>> just return.
>>
>
> This will abort if Qemu sends more bytes than the number requested in
> grlib_apbuart_can_receive, so this would be a failure from Qemu not the
> guest.
OK. Thanks, applied.
> Regards,
>
> --
> Fabien Chouteau
