From 8b79d4e994074a058b6876dce843ee112656258d Mon Sep 17 00:00:00 2001
From: Palmer Dabbelt <palmer@rivosinc.com>
Date: Wed, 14 Feb 2024 07:34:30 -0800
Subject: [PATCH 1/3] tty: hvc: Don't enable the RISC-V SBI console by default
The new SBI console has the same problem as the old one: there's only
one shared backing hardware and no synchronization, so the two drivers
end up stepping on each other. This was the same issue the old SBI-0.1
console drivers had, but that was disabled by default when SBI-0.1 was.
So just mark the new driver as nonportable.
Reported-by: Emil Renner Berthing <kernel@esmil.dk>
Fixes: 88ead68e764c ("tty: Add SBI debug console support to HVC SBI driver")
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240214153429.16484-2-palmer@rivosinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/hvc/Kconfig | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
index 6e05c5c7bca1a..c2a4e88b328f3 100644
--- a/drivers/tty/hvc/Kconfig
+++ b/drivers/tty/hvc/Kconfig
@@ -108,13 +108,15 @@ config HVC_DCC_SERIALIZE_SMP
config HVC_RISCV_SBI
bool "RISC-V SBI console support"
- depends on RISCV_SBI
+ depends on RISCV_SBI && NONPORTABLE
select HVC_DRIVER
help
This enables support for console output via RISC-V SBI calls, which
- is normally used only during boot to output printk.
+ is normally used only during boot to output printk. This driver
+ conflicts with real console drivers and should not be enabled on
+ systems that directly access the console.
- If you don't know what do to here, say Y.
+ If you don't know what do to here, say N.
config HVCS
tristate "IBM Hypervisor Virtual Console Server support"
From f418ae73311deb901c0110b08d1bbafc20c1820e Mon Sep 17 00:00:00 2001
From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Date: Fri, 16 Feb 2024 23:47:07 +0100
Subject: [PATCH 2/3] serial: stm32: do not always set SER_RS485_RX_DURING_TX
if RS485 is enabled
Before commit 07c30ea5861f ("serial: Do not hold the port lock when setting
rx-during-tx GPIO") the SER_RS485_RX_DURING_TX flag was only set if the
rx-during-tx mode was not controlled by a GPIO. Now the flag is set
unconditionally when RS485 is enabled. This results in an incorrect setting
if the rx-during-tx GPIO is not asserted.
Fix this by setting the flag only if the rx-during-tx mode is not
controlled by a GPIO and thus restore the correct behaviour.
Cc: stable@vger.kernel.org # 6.6+
Fixes: 07c30ea5861f ("serial: Do not hold the port lock when setting rx-during-tx GPIO")
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20240216224709.9928-1-l.sanfilippo@kunbus.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/stm32-usart.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 794b775127403..693e932d6feb5 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -251,7 +251,9 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter
writel_relaxed(cr3, port->membase + ofs->cr3);
writel_relaxed(cr1, port->membase + ofs->cr1);
- rs485conf->flags |= SER_RS485_RX_DURING_TX;
+ if (!port->rs485_rx_during_tx_gpio)
+ rs485conf->flags |= SER_RS485_RX_DURING_TX;
+
} else {
stm32_usart_clr_bits(port, ofs->cr3,
USART_CR3_DEM | USART_CR3_DEP);
From 3b69e32e151bc4a4e3c785cbdb1f918d5ee337ed Mon Sep 17 00:00:00 2001
From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Date: Fri, 16 Feb 2024 23:47:08 +0100
Subject: [PATCH 3/3] serial: amba-pl011: Fix DMA transmission in RS485 mode
When DMA is used in RS485 mode make sure that the UARTs tx section is
enabled before the DMA buffers are queued for transmission.
Cc: stable@vger.kernel.org
Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support")
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20240216224709.9928-2-l.sanfilippo@kunbus.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/amba-pl011.c | 60 ++++++++++++++++-----------------
1 file changed, 30 insertions(+), 30 deletions(-)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index fccec1698a541..cf2c890a560f0 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1339,11 +1339,41 @@ static void pl011_start_tx_pio(struct uart_amba_port *uap)
}
}
+static void pl011_rs485_tx_start(struct uart_amba_port *uap)
+{
+ struct uart_port *port = &uap->port;
+ u32 cr;
+
+ /* Enable transmitter */
+ cr = pl011_read(uap, REG_CR);
+ cr |= UART011_CR_TXE;
+
+ /* Disable receiver if half-duplex */
+ if (!(port->rs485.flags & SER_RS485_RX_DURING_TX))
+ cr &= ~UART011_CR_RXE;
+
+ if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
+ cr &= ~UART011_CR_RTS;
+ else
+ cr |= UART011_CR_RTS;
+
+ pl011_write(cr, uap, REG_CR);
+
+ if (port->rs485.delay_rts_before_send)
+ mdelay(port->rs485.delay_rts_before_send);
+
+ uap->rs485_tx_started = true;
+}
+
static void pl011_start_tx(struct uart_port *port)
{
struct uart_amba_port *uap =
container_of(port, struct uart_amba_port, port);
+ if ((uap->port.rs485.flags & SER_RS485_ENABLED) &&
+ !uap->rs485_tx_started)
+ pl011_rs485_tx_start(uap);
+
if (!pl011_dma_tx_start(uap))
pl011_start_tx_pio(uap);
}
@@ -1424,42 +1454,12 @@ static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c,
return true;
}
-static void pl011_rs485_tx_start(struct uart_amba_port *uap)
-{
- struct uart_port *port = &uap->port;
- u32 cr;
-
- /* Enable transmitter */
- cr = pl011_read(uap, REG_CR);
- cr |= UART011_CR_TXE;
-
- /* Disable receiver if half-duplex */
- if (!(port->rs485.flags & SER_RS485_RX_DURING_TX))
- cr &= ~UART011_CR_RXE;
-
- if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
- cr &= ~UART011_CR_RTS;
- else
- cr |= UART011_CR_RTS;
-
- pl011_write(cr, uap, REG_CR);
-
- if (port->rs485.delay_rts_before_send)
- mdelay(port->rs485.delay_rts_before_send);
-
- uap->rs485_tx_started = true;
-}
-
/* Returns true if tx interrupts have to be (kept) enabled */
static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq)
{
struct circ_buf *xmit = &uap->port.state->xmit;
int count = uap->fifosize >> 1;
- if ((uap->port.rs485.flags & SER_RS485_ENABLED) &&
- !uap->rs485_tx_started)
- pl011_rs485_tx_start(uap);
-
if (uap->port.x_char) {
if (!pl011_tx_char(uap, uap->port.x_char, from_irq))
return true;