diff options
| -rw-r--r-- | hw/lpc-uart.c | 100 |
1 files changed, 74 insertions, 26 deletions
diff --git a/hw/lpc-uart.c b/hw/lpc-uart.c index 979a617..10c5ed4 100644 --- a/hw/lpc-uart.c +++ b/hw/lpc-uart.c @@ -56,6 +56,7 @@ DEFINE_LOG_ENTRY(OPAL_RC_UART_INIT, OPAL_PLATFORM_ERR_EVT, OPAL_UART, static struct lock uart_lock = LOCK_UNLOCKED; static struct dt_node *uart_node; static uint32_t uart_base; +static uint64_t uart_tx_full_time; static bool has_irq = false, irq_ok, rx_full, tx_full; static uint8_t tx_room; static uint8_t cached_ier; @@ -95,28 +96,59 @@ static inline void uart_write(unsigned int reg, uint8_t val) lpc_outb(val, uart_base + reg); } -static void uart_check_tx_room(void) +static bool uart_check_tx_room(void) { + if (tx_room) + return true; + if (uart_read(REG_LSR) & LSR_THRE) { /* FIFO is 16 entries */ tx_room = 16; tx_full = false; + return true; } + + return false; } -static void uart_wait_tx_room(void) +/* Must be called with UART lock held */ +static void uart_write_thr(uint8_t val) { - while (!tx_room) { - uart_check_tx_room(); - if (!tx_room) { - smt_lowest(); - do { - barrier(); - uart_check_tx_room(); - } while (!tx_room); + uart_write(REG_THR, val); + + tx_room--; + if (tx_room == 0) { + if (!uart_check_tx_room()) + uart_tx_full_time = mftb(); + } +} + +static bool uart_timed_out(unsigned long msecs) +{ + if (uart_check_tx_room()) + return false; + + if (tb_compare(mftb(), uart_tx_full_time + msecs_to_tb(msecs)) == TB_AAFTERB) + return true; + + return false; +} + +static bool uart_wait_tx_room(void) +{ + if (uart_check_tx_room()) + return true; + + smt_lowest(); + while (!uart_check_tx_room()) { + if (uart_timed_out(100)) { smt_medium(); + return false; } } + smt_medium(); + + return true; } static void uart_update_ier(void) @@ -160,18 +192,20 @@ static size_t uart_con_write(const char *buf, size_t len) return written; lock(&uart_lock); - while(written < len) { - if (tx_room == 0) { - uart_wait_tx_room(); - if (tx_room == 0) - goto bail; - } else { - uart_write(REG_THR, buf[written++]); - tx_room--; - } + while (written < len) { + if (!uart_wait_tx_room()) + break; + + uart_write_thr(buf[written++]); + } + + if (!written && uart_timed_out(1000)) { + unlock(&uart_lock); + return len; /* swallow data */ } - bail: + unlock(&uart_lock); + return written; } @@ -232,16 +266,19 @@ static int64_t uart_con_flush(void) tx_full = true; break; } - uart_write(REG_THR, out_buf[out_buf_cons++]); + + uart_write_thr(out_buf[out_buf_cons++]); out_buf_cons %= OUT_BUF_SIZE; - tx_room--; } if (tx_full != tx_was_full) uart_update_ier(); if (out_buf_prod != out_buf_cons) { /* Return busy if nothing was flushed this call */ - if (out_buf_cons == out_buf_cons_initial) + if (out_buf_cons == out_buf_cons_initial) { + if (uart_timed_out(1000)) + return OPAL_TIMEOUT; return OPAL_BUSY; + } /* Return partial if there's more to flush */ return OPAL_PARTIAL; } @@ -259,6 +296,7 @@ static int64_t uart_opal_write(int64_t term_number, __be64 *__length, const uint8_t *buffer) { size_t written = 0, len = be64_to_cpu(*__length); + int64_t ret = OPAL_SUCCESS; if (term_number != 0) return OPAL_PARAMETER; @@ -275,24 +313,34 @@ static int64_t uart_opal_write(int64_t term_number, __be64 *__length, /* Flush out buffer again */ uart_con_flush(); + if (!written && uart_timed_out(1000)) + ret = OPAL_TIMEOUT; unlock(&uart_lock); *__length = cpu_to_be64(written); - return OPAL_SUCCESS; + return ret; } static int64_t uart_opal_write_buffer_space(int64_t term_number, __be64 *__length) { + int64_t ret = OPAL_SUCCESS; + int64_t tx_buf_len; + if (term_number != 0) return OPAL_PARAMETER; lock(&uart_lock); - *__length = cpu_to_be64(uart_tx_buf_space()); + tx_buf_len = uart_tx_buf_space(); + + if ((tx_buf_len < be64_to_cpu(*__length)) && uart_timed_out(1000)) + ret = OPAL_TIMEOUT; + + *__length = cpu_to_be64(tx_buf_len); unlock(&uart_lock); - return OPAL_SUCCESS; + return ret; } /* Must be called with UART lock held */ |