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cr50: Enable EC UART bit banging.

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Cr50 needs to be able to bit bang the EC UART in order to flash certain
ECs such as the STM32 family.  This is because the UART block on the
chip has no provision to change the parity which is necessary for the
STM32 bootloader protocol.

This commit adds a configuration to bit bang the EC UART. It's been
tested at 9600 baud.

BUG=b:35648297
BRANCH=cr50
TEST=With a logic analyzer, verify that TX to the EC can be bit banged
with no issues at 9600.
TEST=With some other changes, verify that cr50 is able to flash an EC
image to an STM32 EC.

Change-Id: Ice72aff133f268b5b7f0868aeec590a21404d1af
Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Reviewed-on: https://chromium-review.googlesource.com/503474
Commit-Ready: Aseda Aboagye <aaboagye@chromium.org>
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
This commit is contained in:
Aseda Aboagye
2017-05-11 13:09:02 -07:00
committed by chrome-bot
parent 27a39b44d1
commit cfcbe9da95
3 changed files with 55 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

45
board/cr50/board.c
View File

@@ -31,6 +31,7 @@
#include "task.h"
#include "tpm_registers.h"
#include "trng.h"
#include "uart_bitbang.h"
#include "uartn.h"
#include "usb_descriptor.h"
#include "usb_hid.h"
@@ -90,6 +91,30 @@ static int device_state_changed(enum device_type device,
static uint32_t board_properties;
static uint8_t reboot_request_posted;
/* Which UARTs we'd like to be able to bitbang. */
struct uart_bitbang_properties bitbang_config = {
.uart = UART_EC,
.tx_gpio = GPIO_DETECT_SERVO, /* This is TX to EC console. */
.rx_gpio = GPIO_EC_TX_CR50_RX,
/*
* The rx/tx_pinmux_regval values MUST agree with the pin config for
* both the TX and RX GPIOs in gpio.inc. Don't change one without
* changing the other.
*/
.tx_pinmux_reg = GBASE(PINMUX) + GOFFSET(PINMUX, DIOB5_SEL),
.tx_pinmux_regval = GC_PINMUX_GPIO1_GPIO3_SEL,
.rx_pinmux_reg = GBASE(PINMUX) + GOFFSET(PINMUX, DIOB6_SEL),
.rx_pinmux_regval = GC_PINMUX_GPIO1_GPIO4_SEL,
};
extern struct deferred_data ec_uart_deferred__data;
void ec_tx_cr50_rx(enum gpio_signal signal)
{
uart_bitbang_receive_char(UART_EC);
/* Let the USART module know that there's new bits to consume. */
hook_call_deferred(&ec_uart_deferred__data, 0);
}
int board_has_ap_usb(void)
{
return !!(board_properties & BOARD_USB_AP);
@@ -589,6 +614,12 @@ static void board_init(void)
/* Enable battery cutoff software support on detachable devices. */
if (system_battery_cutoff_support_required())
set_up_battery_cutoff_monitor();
/*
* The interrupt is enabled by default, but we only want it enabled when
* bit banging mode is active.
*/
gpio_disable_interrupt(GPIO_EC_TX_CR50_RX);
}
DECLARE_HOOK(HOOK_INIT, board_init, HOOK_PRIO_DEFAULT);
@@ -772,6 +803,13 @@ static int servo_state_unknown(void)
static void enable_uart(int uart)
{
/*
* For the EC UART, we can't connect the TX pin to the UART block when
* it's in bit bang mode.
*/
if ((uart == UART_EC) && uart_bitbang_is_enabled(uart))
return;
/* Enable RX and TX on the UART peripheral */
uartn_enable(uart);
@@ -861,6 +899,10 @@ static void servo_attached(void)
if (servo_state_unknown())
return;
#ifdef CONFIG_UART_BITBANG
uart_bitbang_disable(bitbang_config.uart);
#endif /* defined(CONFIG_UART_BITBANG) */
/* Update the device state */
device_state_changed(DEVICE_SERVO, DEVICE_STATE_ON);
@@ -911,7 +953,8 @@ void device_state_on(enum gpio_signal signal)
hook_notify(HOOK_CHIPSET_RESUME);
break;
case GPIO_DETECT_EC:
if (device_state_changed(DEVICE_EC, DEVICE_STATE_ON))
if (device_state_changed(DEVICE_EC, DEVICE_STATE_ON) &&
!uart_bitbang_is_enabled(UART_EC))
enable_uart(UART_EC);
break;
case GPIO_DETECT_SERVO:

4
board/cr50/board.h
View File

@@ -106,6 +106,9 @@
#undef CONFIG_USB_MAXPOWER_MA
#define CONFIG_USB_MAXPOWER_MA 0
/* Need to be able to bitbang the EC UART for updates through CCD. */
#define CONFIG_UART_BITBANG
/* Enable SPI Master (SPI) module */
#define CONFIG_SPI_MASTER
#define CONFIG_SPI_MASTER_NO_CS_GPIOS
@@ -177,6 +180,7 @@ void board_configure_deep_sleep_wakepins(void);
void tpm_rst_deasserted(enum gpio_signal signal);
void device_state_on(enum gpio_signal signal);
void post_reboot_request(void);
void ec_tx_cr50_rx(enum gpio_signal signal);
/* Special controls over EC and AP */
void assert_sys_rst(void);

7
board/cr50/gpio.inc
View File

@@ -58,8 +58,14 @@
GPIO_INT(TPM_RST_L, PIN(1, 0), GPIO_INT_RISING, tpm_rst_deasserted)
GPIO_INT(DETECT_AP, PIN(1, 1), GPIO_INT_HIGH, device_state_on)
GPIO_INT(DETECT_EC, PIN(1, 2), GPIO_INT_HIGH, device_state_on)
/*
* DETECT_SERVO and EC_TX_CR50_RX pins must NOT be changed without also changing
* the pinmux_regval fields in the bitbang_config in board.c. The pinmux values
* in the config assume the pin definitions here.
*/
GPIO_INT(DETECT_SERVO, PIN(1, 3), GPIO_INT_HIGH | GPIO_PULL_DOWN,
device_state_on)
GPIO_INT(EC_TX_CR50_RX, PIN(1, 4), GPIO_INT_FALLING, ec_tx_cr50_rx)
/* Pull this low to interrupt the AP */
GPIO(INT_AP_L, PIN(0, 0), GPIO_OUT_HIGH)
@@ -148,6 +154,7 @@ PINMUX(FUNC(UART2_RX), B6, DIO_INPUT) /* EC console */
* damage both servo and cr50.
*/
PINMUX(GPIO(DETECT_EC), B6, DIO_INPUT)
PINMUX(GPIO(EC_TX_CR50_RX), B6, DIO_INPUT)
PINMUX(GPIO(DETECT_SERVO), B5, DIO_INPUT)
/*