From c9cc3aaa0281fec487794a473c82544bb7ac1b68 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sat, 12 Nov 2016 21:32:37 +0000 Subject: thunderbolt: Use Device ROM retrieved from EFI MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Macs with Thunderbolt 1 do not have a unit-specific DROM: The DROM is empty with uid 0x1000000000000. (Apple started factory-burning a unit- specific DROM with Thunderbolt 2.) Instead, the NHI EFI driver supplies a DROM in a device property. Use it if available. It's only available when booting with the efistub. If it's not available, silently fall back to our hardcoded DROM. The size of the DROM is always 256 bytes. The number is hardcoded into the NHI EFI driver. This commit can deal with an arbitrary size however, just in case they ever change that. Background information: The EFI firmware volume contains ROM files for the NHI, GMUX and several other chips as well as key material. This strategy allows Apple to deploy ROM or key updates by simply publishing an EFI firmware update on their website. Drivers do not access those files directly but rather through a file server via EFI protocol AC5E4829-A8FD-440B-AF33-9FFE013B12D8. Files are identified by GUID, the NHI DROM has 339370BD-CFC6-4454-8EF7-704653120818. The NHI EFI driver amends that file with a unit-specific uid. The uid has 64 bit but its entropy is much lower: 24 bit represent the model, 24 bit are taken from a serial number, 16 bit are fixed. The NHI EFI driver obtains the serial number via the DataHub protocol, copies it into the DROM, calculates the CRC and submits the result as a device property. A modification is needed in the resume code where we currently read the uid of all switches in the hierarchy to detect plug events that occurred during sleep. On Thunderbolt 1 root switches this will now lead to a mismatch between the uid of the empty DROM and the EFI DROM. Exempt the root switch from this check: It's built in, so the uid should never change. However we continue to *read* the uid of the root switch, this seems like a good way to test its reachability after resume. Tested-by: Lukas Wunner [MacBookPro9,1] Tested-by: Pierre Moreau [MacBookPro11,3] Signed-off-by: Lukas Wunner Signed-off-by: Matt Fleming Acked-by: Andreas Noever Cc: Ard Biesheuvel Cc: Linus Torvalds Cc: Pedro Vilaça Cc: Peter Jones Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20161112213237.8804-10-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar --- drivers/thunderbolt/Kconfig | 1 + drivers/thunderbolt/eeprom.c | 43 +++++++++++++++++++++++++++++++++++++++++++ drivers/thunderbolt/switch.c | 2 +- 3 files changed, 45 insertions(+), 1 deletion(-) (limited to 'drivers/thunderbolt') diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig index c121acc15bfe..0056df7f3c09 100644 --- a/drivers/thunderbolt/Kconfig +++ b/drivers/thunderbolt/Kconfig @@ -1,6 +1,7 @@ menuconfig THUNDERBOLT tristate "Thunderbolt support for Apple devices" depends on PCI + select APPLE_PROPERTIES select CRC32 help Cactus Ridge Thunderbolt Controller driver diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c index 2b9602c2c355..6392990c984d 100644 --- a/drivers/thunderbolt/eeprom.c +++ b/drivers/thunderbolt/eeprom.c @@ -5,6 +5,7 @@ */ #include +#include #include #include "tb.h" @@ -359,6 +360,40 @@ static int tb_drom_parse_entries(struct tb_switch *sw) return 0; } +/** + * tb_drom_copy_efi - copy drom supplied by EFI to sw->drom if present + */ +static int tb_drom_copy_efi(struct tb_switch *sw, u16 *size) +{ + struct device *dev = &sw->tb->nhi->pdev->dev; + int len, res; + + len = device_property_read_u8_array(dev, "ThunderboltDROM", NULL, 0); + if (len < 0 || len < sizeof(struct tb_drom_header)) + return -EINVAL; + + sw->drom = kmalloc(len, GFP_KERNEL); + if (!sw->drom) + return -ENOMEM; + + res = device_property_read_u8_array(dev, "ThunderboltDROM", sw->drom, + len); + if (res) + goto err; + + *size = ((struct tb_drom_header *)sw->drom)->data_len + + TB_DROM_DATA_START; + if (*size > len) + goto err; + + return 0; + +err: + kfree(sw->drom); + sw->drom = NULL; + return -EINVAL; +} + /** * tb_drom_read - copy drom to sw->drom and parse it */ @@ -373,6 +408,13 @@ int tb_drom_read(struct tb_switch *sw) return 0; if (tb_route(sw) == 0) { + /* + * Apple's NHI EFI driver supplies a DROM for the root switch + * in a device property. Use it if available. + */ + if (tb_drom_copy_efi(sw, &size) == 0) + goto parse; + /* * The root switch contains only a dummy drom (header only, * no entries). Hardcode the configuration here. @@ -418,6 +460,7 @@ int tb_drom_read(struct tb_switch *sw) if (res) goto err; +parse: header = (void *) sw->drom; if (header->data_len + TB_DROM_DATA_START != size) { diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index 9840fdecb73b..c6f30b1695a9 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -460,7 +460,7 @@ int tb_switch_resume(struct tb_switch *sw) tb_sw_warn(sw, "uid read failed\n"); return err; } - if (sw->uid != uid) { + if (sw != sw->tb->root_switch && sw->uid != uid) { tb_sw_info(sw, "changed while suspended (uid %#llx -> %#llx)\n", sw->uid, uid); -- cgit v1.2.3