From: Douglas Anderson <dianders@chromium.org>
To: jason.wessel@windriver.com, daniel.thompson@linaro.org,
gregkh@linuxfoundation.org
Cc: kgdb-bugreport@lists.sourceforge.net, mingo@redhat.com,
hpa@zytor.com, bp@alien8.de, linux-serial@vger.kernel.org,
agross@kernel.org, tglx@linutronix.de, frowand.list@gmail.com,
bjorn.andersson@linaro.org, jslaby@suse.com,
catalin.marinas@arm.com, corbet@lwn.net, will@kernel.org,
Douglas Anderson <dianders@chromium.org>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 8/9] serial: qcom_geni_serial: Support earlycon_kgdboc
Date: Tue, 21 Apr 2020 14:14:46 -0700 [thread overview]
Message-ID: <20200421141234.v2.8.If2deff9679a62c1ce1b8f2558a8635dc837adf8c@changeid> (raw)
In-Reply-To: <20200421211447.193860-1-dianders@chromium.org>
Implement the read() function in the early console driver. With
recent kgdb patches this allows you to use kgdb to debug fairly early
into the system boot.
We only bother implementing this if polling is enabled since kgdb
can't be enabled without that.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Changes in v2: None
drivers/tty/serial/qcom_geni_serial.c | 32 +++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 6119090ce045..4563d152b39e 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -1090,6 +1090,36 @@ static void qcom_geni_serial_earlycon_write(struct console *con,
__qcom_geni_serial_console_write(&dev->port, s, n);
}
+#ifdef CONFIG_CONSOLE_POLL
+static int qcom_geni_serial_earlycon_read(struct console *con,
+ char *s, unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+ struct uart_port *uport = &dev->port;
+ int num_read = 0;
+ int ch;
+
+ while (num_read < n) {
+ ch = qcom_geni_serial_get_char(uport);
+ if (ch == NO_POLL_CHAR)
+ break;
+ s[num_read++] = ch;
+ }
+
+ return num_read;
+}
+
+static void __init qcom_geni_serial_enable_early_read(struct geni_se *se,
+ struct console *con)
+{
+ geni_se_setup_s_cmd(se, UART_START_READ, 0);
+ con->read = qcom_geni_serial_earlycon_read;
+}
+#else
+static inline void qcom_geni_serial_enable_early_read(struct geni_se *se,
+ struct console *con) { ; }
+#endif
+
static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev,
const char *opt)
{
@@ -1136,6 +1166,8 @@ static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev,
dev->con->write = qcom_geni_serial_earlycon_write;
dev->con->setup = NULL;
+ qcom_geni_serial_enable_early_read(&se, dev->con);
+
return 0;
}
OF_EARLYCON_DECLARE(qcom_geni, "qcom,geni-debug-uart",
--
2.26.1.301.g55bc3eb7cb9-goog
next prev parent reply other threads:[~2020-04-21 21:15 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 21:14 [PATCH v2 0/9] kgdb: Support late serial drivers; enable early debug w/ boot consoles Douglas Anderson
2020-04-21 21:14 ` [PATCH v2 1/9] kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb Douglas Anderson
2020-04-27 13:40 ` Daniel Thompson
2020-04-21 21:14 ` [PATCH v2 2/9] Revert "kgdboc: disable the console lock when in kgdb" Douglas Anderson
2020-04-27 13:41 ` Daniel Thompson
2020-04-21 21:14 ` [PATCH v2 3/9] kgdboc: Use a platform device to handle tty drivers showing up late Douglas Anderson
2020-04-27 14:19 ` Daniel Thompson
2020-04-21 21:14 ` [PATCH v2 4/9] kgdb: Delay "kgdbwait" to dbg_late_init() by default Douglas Anderson
2020-04-27 15:42 ` Daniel Thompson
2020-04-21 21:14 ` [PATCH v2 5/9] arm64: Add call_break_hook() to early_brk64() for early kgdb Douglas Anderson
2020-04-27 16:52 ` Daniel Thompson
2020-04-21 21:14 ` [PATCH v2 6/9] kgdboc: Add earlycon_kgdboc to support early kgdb using boot consoles Douglas Anderson
2020-04-27 16:36 ` Daniel Thompson
2020-04-28 21:32 ` Doug Anderson
2020-04-21 21:14 ` [PATCH v2 7/9] Documentation: kgdboc: Document new earlycon_kgdboc parameter Douglas Anderson
2020-04-27 16:46 ` Daniel Thompson
2020-04-28 21:32 ` Doug Anderson
2020-04-21 21:14 ` Douglas Anderson [this message]
2020-04-27 16:48 ` [PATCH v2 8/9] serial: qcom_geni_serial: Support earlycon_kgdboc Daniel Thompson
2020-04-21 21:14 ` [PATCH v2 9/9] serial: 8250_early: " Douglas Anderson
2020-04-27 16:50 ` Daniel Thompson
2020-04-23 13:50 ` [PATCH v2 0/9] kgdb: Support late serial drivers; enable early debug w/ boot consoles Greg KH
2020-04-24 8:32 ` Sumit Garg
2020-04-24 10:13 ` Daniel Thompson
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