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Subject[PATCH v2 1/4] ACPI / EC: Cleanup first_ec/boot_ec code
Date
In order to support full ECDT (driving the ECDT EC after probing the
namespace EC), we need to change our EC device alloc/free algorithm, ensure
not to free old boot EC before qualifying new boot EC.
This patch achieves this by cleaning up first_ec/boot_ec logic:
1. first_ec: used to perform transactions, so it is assigned in new
acpi_ec_setup() function.
2. boot_ec: used to track early EC device, so it is assigned in new
acpi_config_boot_ec() function which explictly tells the driver to save
the EC device as early EC device.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=115021
Reported-and-tested-by: Luya Tshimbalanga <luya@fedoraproject.org>
Tested-by: Jonh Henderson <jw.hendy@gmail.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Peter Wu <peter@lekensteyn.nl>
---
drivers/acpi/ec.c | 96 +++++++++++++++++++++++++++++++++++------------------
1 file changed, 63 insertions(+), 33 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 1925589..9eab651 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -184,6 +184,7 @@ static void acpi_ec_event_processor(struct work_struct *work);

struct acpi_ec *boot_ec, *first_ec;
EXPORT_SYMBOL(first_ec);
+static bool boot_ec_is_ecdt = false;
static struct workqueue_struct *ec_query_wq;

static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
@@ -1304,7 +1305,16 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address,
static acpi_status
ec_parse_io_ports(struct acpi_resource *resource, void *context);

-static struct acpi_ec *make_acpi_ec(void)
+static void acpi_ec_free(struct acpi_ec *ec)
+{
+ if (first_ec == ec)
+ first_ec = NULL;
+ if (boot_ec == ec)
+ boot_ec = NULL;
+ kfree(ec);
+}
+
+static struct acpi_ec *acpi_ec_alloc(void)
{
struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);

@@ -1365,6 +1375,11 @@ ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
return AE_CTRL_TERMINATE;
}

+/*
+ * Note: This function returns an error code only when the address space
+ * handler is not installed, which means "not able to handle
+ * transactions".
+ */
static int ec_install_handlers(struct acpi_ec *ec)
{
acpi_status status;
@@ -1440,21 +1455,49 @@ static void ec_remove_handlers(struct acpi_ec *ec)
}
}

-static struct acpi_ec *acpi_ec_alloc(void)
+static int acpi_ec_setup(struct acpi_ec *ec)
{
- struct acpi_ec *ec;
+ int ret;

- /* Check for boot EC */
- if (boot_ec) {
- ec = boot_ec;
- boot_ec = NULL;
- ec_remove_handlers(ec);
- if (first_ec == ec)
- first_ec = NULL;
- } else {
- ec = make_acpi_ec();
+ ret = ec_install_handlers(ec);
+ if (ret)
+ return ret;
+
+ /* First EC capable of handling transactions */
+ if (!first_ec) {
+ first_ec = ec;
+ acpi_handle_info(first_ec->handle, "Used as first EC\n");
}
- return ec;
+
+ acpi_handle_info(ec->handle,
+ "GPE=0x%lx, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
+ ec->gpe, ec->command_addr, ec->data_addr);
+ return ret;
+}
+
+static int acpi_config_boot_ec(struct acpi_ec *ec, bool is_ecdt)
+{
+ int ret;
+
+ if (boot_ec)
+ ec_remove_handlers(boot_ec);
+
+ /* Unset old boot EC */
+ if (boot_ec != ec)
+ acpi_ec_free(boot_ec);
+
+ ret = acpi_ec_setup(ec);
+ if (ret)
+ return ret;
+
+ /* Set new boot EC */
+ if (!boot_ec) {
+ boot_ec = ec;
+ boot_ec_is_ecdt = is_ecdt;
+ acpi_handle_info(boot_ec->handle, "Used as boot %s EC\n",
+ is_ecdt ? "ECDT" : "DSDT");
+ }
+ return ret;
}

static int acpi_ec_add(struct acpi_device *device)
@@ -1470,7 +1513,7 @@ static int acpi_ec_add(struct acpi_device *device)
return -ENOMEM;
if (ec_parse_device(device->handle, 0, ec, NULL) !=
AE_CTRL_TERMINATE) {
- kfree(ec);
+ acpi_ec_free(ec);
return -EINVAL;
}

@@ -1478,8 +1521,6 @@ static int acpi_ec_add(struct acpi_device *device)
acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
acpi_ec_register_query_methods, NULL, ec, NULL);

- if (!first_ec)
- first_ec = ec;
device->driver_data = ec;

ret = !!request_region(ec->data_addr, 1, "EC data");
@@ -1487,10 +1528,7 @@ static int acpi_ec_add(struct acpi_device *device)
ret = !!request_region(ec->command_addr, 1, "EC cmd");
WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);

- pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
- ec->gpe, ec->command_addr, ec->data_addr);
-
- ret = ec_install_handlers(ec);
+ ret = acpi_config_boot_ec(ec, false);

/* Reprobe devices depending on the EC */
acpi_walk_dep_device_list(ec->handle);
@@ -1513,9 +1551,7 @@ static int acpi_ec_remove(struct acpi_device *device)
release_region(ec->data_addr, 1);
release_region(ec->command_addr, 1);
device->driver_data = NULL;
- if (ec == first_ec)
- first_ec = NULL;
- kfree(ec);
+ acpi_ec_free(ec);
return 0;
}

@@ -1567,13 +1603,10 @@ int __init acpi_ec_dsdt_probe(void)
ret = -ENODEV;
goto error;
}
- ret = ec_install_handlers(ec);
-
+ ret = acpi_config_boot_ec(ec, false);
error:
if (ret)
- kfree(ec);
- else
- first_ec = boot_ec = ec;
+ acpi_ec_free(ec);
return ret;
}

@@ -1671,7 +1704,6 @@ int __init acpi_ec_ecdt_probe(void)
goto error;
}

- pr_info("EC description table is found, configuring boot EC\n");
if (EC_FLAGS_CORRECT_ECDT) {
ec->command_addr = ecdt_ptr->data.address;
ec->data_addr = ecdt_ptr->control.address;
@@ -1681,12 +1713,10 @@ int __init acpi_ec_ecdt_probe(void)
}
ec->gpe = ecdt_ptr->gpe;
ec->handle = ACPI_ROOT_OBJECT;
- ret = ec_install_handlers(ec);
+ ret = acpi_config_boot_ec(ec, true);
error:
if (ret)
- kfree(ec);
- else
- first_ec = boot_ec = ec;
+ acpi_ec_free(ec);
return ret;
}

--
1.7.10
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