Author: imp
Date: Sun Dec 22 23:33:27 2013
New Revision: 259753
URL: http://svnweb.freebsd.org/changeset/base/259753
Log:
Direct Commit of mountroot> prompt fix r259748 (since there's no sane
branching relationship between that branch and this one and since the
more general fix in head may be too risky for a stbale branch this
mature):
Fix mountroot> prompt eating most of the characters by not enabling
RXRDY interrupts in the attach routine. Instead, defer this until the
first interrupt we see after the device is opened. Given the console
use case, we're guaranteed to get a TXRDY interrupt before any reads
are posted due to boot messages, which makes this work.
The real fix is to use cngrab/cnungrab function pointers to disable
RXRDY interrupts while grabbed. However, that touches the MI uart
code, so was disallowed for 10.0 due to the lateness of the hour this
fix was proposed. It works for mountroot, the most common atmel kernel
prompt use cases, but wouldn't work for GELI since it prompts later in
the boot process.
Modified:
stable/9/sys/arm/at91/uart_dev_at91usart.c
Modified: stable/9/sys/arm/at91/uart_dev_at91usart.c
==============================================================================
--- stable/9/sys/arm/at91/uart_dev_at91usart.c Sun Dec 22 23:31:04 2013
(r259752)
+++ stable/9/sys/arm/at91/uart_dev_at91usart.c Sun Dec 22 23:33:27 2013
(r259753)
@@ -63,7 +63,8 @@ struct at91_usart_softc {
bus_dma_tag_t tx_tag;
bus_dmamap_t tx_map;
uint32_t flags;
-#define HAS_TIMEOUT 1
+#define HAS_TIMEOUT 0x1
+#define NEEDS_RXRDY 0x4
bus_dma_tag_t rx_tag;
struct at91_usart_rx ping_pong[2];
struct at91_usart_rx *ping;
@@ -425,7 +426,13 @@ at91_usart_bus_attach(struct uart_softc
WR4(&sc->sc_bas, USART_IER, USART_CSR_TIMEOUT |
USART_CSR_RXBUFF | USART_CSR_ENDRX);
} else {
- WR4(&sc->sc_bas, USART_IER, USART_CSR_RXRDY);
+ /*
+ * Defer turning on the RXRDY bit until we're opened. This is
to make the
+ * mountroot prompt work before we've opened the console. This
is a workaround
+ * for not being able to change the UART interface for the 10.0
release.
+ */
+ atsc->flags |= NEEDS_RXRDY;
+ /* WR4(&sc->sc_bas, USART_IER, USART_CSR_RXRDY); */
}
WR4(&sc->sc_bas, USART_IER, USART_CSR_RXBRK);
errout:
@@ -530,6 +537,13 @@ at91_usart_bus_ipend(struct uart_softc *
ipend = 0;
atsc = (struct at91_usart_softc *)sc;
uart_lock(sc->sc_hwmtx);
+
+ /* Kludge -- Enable the RXRDY we deferred in attach */
+ if (sc->sc_opened && (atsc->flags & NEEDS_RXRDY)) {
+ WR4(&sc->sc_bas, USART_IER, USART_CSR_RXRDY);
+ atsc->flags &= ~NEEDS_RXRDY;
+ }
+
csr = RD4(&sc->sc_bas, USART_CSR);
if (csr & USART_CSR_ENDTX) {
bus_dmamap_sync(atsc->tx_tag, atsc->tx_map,
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