From mboxrd@z Thu Jan 1 00:00:00 1970 From: andre.przywara@arm.com (Andre Przywara) Date: Wed, 4 Mar 2015 17:59:52 +0000 Subject: [PATCH v2 08/10] drivers: PL011: allow avoiding UART enabling/disabling In-Reply-To: <1425491994-23913-1-git-send-email-andre.przywara@arm.com> References: <1425491994-23913-1-git-send-email-andre.przywara@arm.com> Message-ID: <1425491994-23913-9-git-send-email-andre.przywara@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The SBSA UART should not be enabled or disabled (it is always on), and consequently the spec lacks the UART_CR register. Add a vendor specific property to skip disabling or enabling of the UART. This will be used later by the SBSA UART support. Signed-off-by: Andre Przywara --- drivers/tty/serial/amba-pl011.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index bca5a3f..fdb9fa5 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -79,6 +79,7 @@ struct vendor_data { bool oversampling; bool dma_threshold; bool cts_event_workaround; + bool always_enabled; unsigned int (*get_fifosize)(struct amba_device *dev); }; @@ -95,6 +96,7 @@ static struct vendor_data vendor_arm = { .oversampling = false, .dma_threshold = false, .cts_event_workaround = false, + .always_enabled = false, .get_fifosize = get_fifosize_arm, }; @@ -110,6 +112,7 @@ static struct vendor_data vendor_st = { .oversampling = true, .dma_threshold = true, .cts_event_workaround = true, + .always_enabled = false, .get_fifosize = get_fifosize_st, }; @@ -2059,7 +2062,7 @@ static void pl011_console_write(struct console *co, const char *s, unsigned int count) { struct uart_amba_port *uap = amba_ports[co->index]; - unsigned int status, old_cr, new_cr; + unsigned int status, old_cr = 0, new_cr; unsigned long flags; int locked = 1; @@ -2076,10 +2079,12 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) /* * First save the CR then disable the interrupts */ - old_cr = readw(uap->port.membase + UART011_CR); - new_cr = old_cr & ~UART011_CR_CTSEN; - new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE; - writew(new_cr, uap->port.membase + UART011_CR); + if (!uap->vendor->always_enabled) { + old_cr = readw(uap->port.membase + UART011_CR); + new_cr = old_cr & ~UART011_CR_CTSEN; + new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE; + writew(new_cr, uap->port.membase + UART011_CR); + } uart_console_write(&uap->port, s, count, pl011_console_putchar); @@ -2090,7 +2095,8 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) do { status = readw(uap->port.membase + UART01x_FR); } while (status & UART01x_FR_BUSY); - writew(old_cr, uap->port.membase + UART011_CR); + if (!uap->vendor->always_enabled) + writew(old_cr, uap->port.membase + UART011_CR); if (locked) spin_unlock(&uap->port.lock); -- 1.7.9.5