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De-feature PL011 UART driver to match generic UART spec 

The Server Base System Architecture document (ARM-DEN-0029)
specifies a generic UART device. The programmer's view of this
generic UART is a subset of the ARM PL011 UART. However, the
current PL011 driver in Trusted Firmware uses some features
that are outside the generic UART specification.

This patch modifies the PL011 driver to exclude features outside
the SBSA generic UART specification by setting the boolean build
option 'PL011_GENERIC_UART=1'. Default value is 0 (use full
PL011 features).

User guide updated.

Fixes ARM-software/tf-issues#216

Change-Id: I6e0eb86f9d69569bc3980fb57e70d6da5d91a737
This commit is contained in:
Juan Castillo 2015-11-16 16:53:38 +00:00
parent f3974ea5b1
commit 12f654b6a8
4 changed files with 22 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Makefile
View File

@ -95,6 +95,8 @@ COLD_BOOT_SINGLE_CPU := 0
# Flag to introduce an infinite loop in BL1 just before it exits into the next
# image. This is meant to help debugging the post-BL2 phase.
SPIN_ON_BL1_EXIT := 0
# Build PL011 UART driver in minimal generic UART mode
PL011_GENERIC_UART := 0
################################################################################
@ -365,6 +367,7 @@ $(eval $(call assert_boolean,PSCI_EXTENDED_STATE_ID))
$(eval $(call assert_boolean,ERROR_DEPRECATED))
$(eval $(call assert_boolean,ENABLE_PLAT_COMPAT))
$(eval $(call assert_boolean,SPIN_ON_BL1_EXIT))
$(eval $(call assert_boolean,PL011_GENERIC_UART))
################################################################################
@ -393,6 +396,7 @@ $(eval $(call add_define,SPIN_ON_BL1_EXIT))
ifdef EL3_PAYLOAD_BASE
$(eval $(call add_define,EL3_PAYLOAD_BASE))
endif
$(eval $(call add_define,PL011_GENERIC_UART))
################################################################################

6
docs/user-guide.md
View File

@ -388,6 +388,12 @@ performed.
payload. Please refer to the "Booting an EL3 payload" section for more
details.
* `PL011_GENERIC_UART`: Boolean option to indicate the PL011 driver that
the underlying hardware is not a full PL011 UART but a minimally compliant
generic UART, which is a subset of the PL011. The driver will not access
any register that is not part of the SBSA generic UART specification.
Default value is 0 (a full PL011 compliant UART is present).
#### ARM development platform specific build options
* `ARM_TSP_RAM_LOCATION`: location of the TSP binary. Options:

2
drivers/arm/pl011/pl011_console.S
View File

@ -60,6 +60,7 @@
func console_core_init
/* Check the input base address */
cbz x0, core_init_fail
#if !PL011_GENERIC_UART
/* Check baud rate and uart clock for sanity */
cbz w1, core_init_fail
cbz w2, core_init_fail
@ -82,6 +83,7 @@ func console_core_init
/* Enable tx, rx, and uart overall */
mov w1, #(PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN)
str w1, [x0, #UARTCR]
#endif
mov w0, #1
ret
core_init_fail:

13
include/drivers/arm/pl011.h
View File

@ -36,17 +36,21 @@
#define UARTRSR 0x004
#define UARTECR 0x004
#define UARTFR 0x018
#define UARTIMSC 0x038
#define UARTRIS 0x03C
#define UARTICR 0x044
/* PL011 registers (out of the SBSA specification) */
#if !PL011_GENERIC_UART
#define UARTILPR 0x020
#define UARTIBRD 0x024
#define UARTFBRD 0x028
#define UARTLCR_H 0x02C
#define UARTCR 0x030
#define UARTIFLS 0x034
#define UARTIMSC 0x038
#define UARTRIS 0x03C
#define UARTMIS 0x040
#define UARTICR 0x044
#define UARTDMACR 0x048
#endif /* !PL011_GENERIC_UART */
/* Data status bits */
#define UART_DATA_ERROR_MASK 0x0F00
@ -69,6 +73,7 @@
#define PL011_UARTFR_RXFE_BIT 4 /* Receive FIFO empty bit in UARTFR register */
/* Control reg bits */
#if !PL011_GENERIC_UART
#define PL011_UARTCR_CTSEN (1 << 15) /* CTS hardware flow control enable */
#define PL011_UARTCR_RTSEN (1 << 14) /* RTS hardware flow control enable */
#define PL011_UARTCR_RTS (1 << 11) /* Request to send */
@ -95,4 +100,6 @@
#define PL011_UARTLCR_H_PEN (1 << 1) /* Parity Enable */
#define PL011_UARTLCR_H_BRK (1 << 0) /* Send break */
#endif /* !PL011_GENERIC_UART */
#endif /* __PL011_H__ */