Hi Nick, Some comments below ...
Missatge de Nick Crews <[email protected]> del dia dj., 11 d’abr. 2019 a les 0:09: > > As part of Chrome OS's FAFT (Fully Automated Firmware Testing) > tests, we need to ensure that the H1 chip is properly setting > some GPIO lines. The h1_gpio attribute exposes the state > of the lines: > - ENTRY_TO_FACT_MODE in BIT(0) > - SPI_CHROME_SEL in BIT(1) > > There are two reasons that I am exposing this in debugfs, > and not as a GPIO: > 1. This is only useful for testing, so end users shouldn't ever > care about this. In fact, if it passes the tests, then the value of > h1_gpio will always be 2, so it would be really uninteresting for users. > 2. This GPIO is not connected to, controlled by, or really even related > to the AP. The GPIO runs between the EC and the H1 security chip. > > Changes in v3: > - Fix documentation to correspond with formatting change in v2. > Changes in v2: > - Zero out the unused fields in the request. > - Format result as "%02x\n" instead of as a decimal. I don't really mind, but wouldn't be more clear prefix with 0x (0x%02x)? > > Signed-off-by: Nick Crews <[email protected]> > --- > drivers/platform/chrome/wilco_ec/debugfs.c | 64 +++++++++++++++++++++- ABI documentation missing. > 1 file changed, 63 insertions(+), 1 deletion(-) > > diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c > b/drivers/platform/chrome/wilco_ec/debugfs.c > index 17c4c9068aaf..1b93243c8954 100644 > --- a/drivers/platform/chrome/wilco_ec/debugfs.c > +++ b/drivers/platform/chrome/wilco_ec/debugfs.c > @@ -4,7 +4,7 @@ > * > * Copyright 2019 Google LLC > * > - * There is only one attribute used for debugging, called raw. > + * The raw attribute is very useful for EC debugging. > * You can write a hexadecimal sentence to raw, and that series of bytes > * will be sent to the EC. Then, you can read the bytes of response > * by reading from raw. > @@ -30,6 +30,16 @@ > * Note that the first 32 bytes of the received MBOX[] will be printed, > * even if some of the data is junk. It is up to you to know how many of > * the first bytes of data are the actual response. > + * > + * There is also another debugfs attribute, called h1_gpio. > + * As part of Chrome OS's FAFT (Fully Automated Firmware Testing) > + * tests, we need to ensure that the H1 chip is properly setting > + * some GPIO lines. The h1_gpio attribute exposes the state > + * of the lines: > + * - ENTRY_TO_FACT_MODE in BIT(0) > + * - SPI_CHROME_SEL in BIT(1) > + > + * Output will formatted with "%02x\n". > */ > > #include <linux/ctype.h> > @@ -189,6 +199,56 @@ static const struct file_operations fops_raw = { > .llseek = no_llseek, > }; > > +#define CMD_KB_CHROME 0x88 > +#define SUB_CMD_H1_GPIO 0x0A > + > +struct h1_gpio_status_request { > + u8 cmd; /* Always CMD_KB_CHROME */ > + u8 reserved; > + u8 sub_cmd; /* Always SUB_CMD_H1_GPIO */ > +} __packed; > + > +struct hi_gpio_status_response { > + u8 status; /* 0 if allowed */ > + u8 val; /* BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL */ > +} __packed; > + > +static ssize_t h1_gpio_read(struct file *file, char __user *user_buf, > + size_t count, loff_t *ppos) > +{ > + struct h1_gpio_status_request rq; > + struct hi_gpio_status_response rs; > + struct wilco_ec_message msg; > + char buf[4]; > + int ret; > + > + memset(&rq, 0, sizeof(rq)); > + rq.cmd = CMD_KB_CHROME; > + rq.sub_cmd = SUB_CMD_H1_GPIO; > + > + memset(&msg, 0, sizeof(msg)); > + msg.type = WILCO_EC_MSG_LEGACY; > + msg.request_data = &rq; > + msg.request_size = sizeof(rq); > + msg.response_data = &rs; > + msg.response_size = sizeof(rs); > + ret = wilco_ec_mailbox(debug_info->ec, &msg); > + if (ret < 0) > + return ret; > + if (rs.status) > + return -EIO; > + > + sprintf(buf, "%02x\n", rs.val); > + > + return simple_read_from_buffer(user_buf, count, ppos, buf, > sizeof(buf)); > +} > + > +static const struct file_operations fops_h1_gpio = { > + .owner = THIS_MODULE, > + .read = h1_gpio_read, > + .llseek = no_llseek, > +}; > + I think that I'd use the DEFINE_DEBUGFS_ATTRIBUTE here. > /** > * wilco_ec_debugfs_probe() - Create the debugfs node > * @pdev: The platform device, probably created in core.c > @@ -210,6 +270,8 @@ static int wilco_ec_debugfs_probe(struct platform_device > *pdev) > if (!debug_info->dir) > return 0; > debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw); > + debugfs_create_file("h1_gpio", 0444, debug_info->dir, NULL, > + &fops_h1_gpio); > > return 0; > } > -- > 2.20.1 > Thanks, Enric
