[PATCH arm/aspeed/ast2500 v3] eSPI: add ASPEED AST2500 eSPI driver to boot a host with PCH runs on eSPI
Greg KH
gregkh at linuxfoundation.org
Sat Mar 24 00:22:20 AEDT 2018
On Fri, Feb 23, 2018 at 10:08:17PM +0800, Haiyue Wang wrote:
> When PCH works under eSPI mode, the PMC (Power Management Controller) in
> PCH is waiting for SUS_ACK from BMC after it alerts SUS_WARN. It is in
> dead loop if no SUS_ACK assert. This is the basic requirement for the BMC
> works as eSPI slave.
>
> Also for the host power on / off actions, from BMC side, the following VW
> (Virtual Wire) messages are done in firmware:
> 1. SLAVE_BOOT_LOAD_DONE / SLAVE_BOOT_LOAD_STATUS
> 2. SUS_ACK
> 3. OOB_RESET_ACK
> 4. HOST_RESET_ACK
>
> Signed-off-by: Haiyue Wang <haiyue.wang at linux.intel.com>
> ---
> v2 -> v3:
> - Remove the unused header file reference.
> - Change some code lines sequence.
>
> v1 -> v2:
> - Fix the checkpatch.pl warning in file espi-slave.rst
> Missing or malformed SPDX-License-Identifier tag in line 1
> #71: FILE: Documentation/misc-devices/espi-slave.rst:1:
> - Make the Kconfig desciption to be more accurate.
> ---
> .../devicetree/bindings/misc/aspeed,espi-slave.txt | 20 ++
> Documentation/misc-devices/espi-slave.rst | 119 ++++++++++
> drivers/misc/Kconfig | 8 +
> drivers/misc/Makefile | 1 +
> drivers/misc/aspeed-espi-slave.c | 261 +++++++++++++++++++++
> 5 files changed, 409 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/misc/aspeed,espi-slave.txt
> create mode 100644 Documentation/misc-devices/espi-slave.rst
> create mode 100644 drivers/misc/aspeed-espi-slave.c
>
> diff --git a/Documentation/devicetree/bindings/misc/aspeed,espi-slave.txt b/Documentation/devicetree/bindings/misc/aspeed,espi-slave.txt
> new file mode 100644
> index 0000000..4f5d47e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/misc/aspeed,espi-slave.txt
> @@ -0,0 +1,20 @@
> +ASPEED eSPI Slave Controller
> +
> +Required properties:
> + - compatible: must be one of:
> + - "aspeed,ast2500-espi-slave"
> +
> + - reg: physical base address of the controller and length of memory mapped
> + region
> +
> + - interrupts: interrupt generated by the controller
> +
> +Example:
> +
> + espi: espi at 1e6ee000 {
> + compatible = "aspeed,ast2500-espi-slave";
> + reg = <0x1e6ee000 0x100>;
> + interrupts = <23>;
> + status = "disabled";
> +};
> +
You need to split this up into a separate patch and get the device tree
maintainers to ack it, right?
> diff --git a/Documentation/misc-devices/espi-slave.rst b/Documentation/misc-devices/espi-slave.rst
> new file mode 100644
> index 0000000..185acd7
> --- /dev/null
> +++ b/Documentation/misc-devices/espi-slave.rst
> @@ -0,0 +1,119 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +==========
> +eSPI Slave
> +==========
> +
> +:Author: Haiyue Wang <haiyue.wang at linux.intel.com>
> +
> +The PCH (**eSPI master**) provides the eSPI to support connection of a
> +BMC (**eSPI slave**) to the platform.
> +
> +The LPC and eSPI interfaces are mutually exclusive. Both use the same
> +pins, but on power-up, a HW strap determines if the eSPI or the LPC bus
> +is operational. Once selected, it’s not possible to change to the other
> +interface.
> +
> +``eSPI Channels and Supported Transactions``
> + +------+---------------------+----------------------+--------------------+
> + | CH # | Channel | Posted Cycles | Non-Posted Cycles |
> + +======+=====================+======================+====================+
> + | 0 | Peripheral | Memory Write, | Memory Read, |
> + | | | Completions | I/O Read/Write |
> + +------+---------------------+----------------------+--------------------+
> + | 1 | Virtual Wire | Virtual Wire GET/PUT | N/A |
> + +------+---------------------+----------------------+--------------------+
> + | 2 | Out-of-Band Message | SMBus Packet GET/PUT | N/A |
> + +------+---------------------+----------------------+--------------------+
> + | 3 | Flash Access | N/A | Flash Read, Write, |
> + | | | | Erase |
> + +------+---------------------+----------------------+--------------------+
> + | N/A | General | Register Accesses | N/A |
> + +------+---------------------+----------------------+--------------------+
> +
> +Virtual Wire Channel (Channel 1) Overview
> +-----------------------------------------
> +
> +The Virtual Wire channel uses a standard message format to communicate
> +several types of signals between the components on the platform::
> +
> + - Sideband and GPIO Pins: System events and other dedicated signals
> + between the PCH and eSPI slave. These signals are tunneled between the
> + two components over eSPI.
> +
> + - Serial IRQ Interrupts: Interrupts are tunneled from the eSPI slave to
> + the PCH. Both edge and triggered interrupts are supported.
> +
> +When PCH runs on eSPI mode, from BMC side, the following VW messages are
> +done in firmware::
> +
> + 1. SLAVE_BOOT_LOAD_DONE / SLAVE_BOOT_LOAD_STATUS
> + 2. SUS_ACK
> + 3. OOB_RESET_ACK
> + 4. HOST_RESET_ACK
> +
> +``eSPI Virtual Wires (VW)``
> + +----------------------+---------+---------------------------------------+
> + |Virtual Wire |PCH Pin |Comments |
> + | |Direction| |
> + +======================+=========+=======================================+
> + |SUS_WARN# |Output |PCH pin is a GPIO when eSPI is enabled.|
> + | | |eSPI controller receives as VW message.|
> + +----------------------+---------+---------------------------------------+
> + |SUS_ACK# |Input |PCH pin is a GPIO when eSPI is enabled.|
> + | | |eSPI controller receives as VW message.|
> + +----------------------+---------+---------------------------------------+
> + |SLAVE_BOOT_LOAD_DONE |Input |Sent when the BMC has completed its |
> + | | |boot process as an indication to |
> + | | |eSPI-MC to continue with the G3 to S0 |
> + | | |exit. |
> + | | |The eSPI Master waits for the assertion|
> + | | |of this virtual wire before proceeding |
> + | | |with the SLP_S5# deassertion. |
> + | | |The intent is that it is never changed |
> + | | |except on a G3 exit - it is reset on a |
> + | | |G3 entry. |
> + +----------------------+---------+---------------------------------------+
> + |SLAVE_BOOT_LOAD_STATUS|Input |Sent upon completion of the Slave Boot |
> + | | |Load from the attached flash. A stat of|
> + | | |1 indicates that the boot code load was|
> + | | |successful and that the integrity of |
> + | | |the image is intact. |
> + +----------------------+---------+---------------------------------------+
> + |HOST_RESET_WARN |Output |Sent from the MC just before the Host |
> + | | |is about to enter reset. Upon receiving|
> + | | |, the BMC must flush and quiesce its |
> + | | |upstream Peripheral Channel request |
> + | | |queues and assert HOST_RESET_ACK VWire.|
> + | | |The MC subsequently completes any |
> + | | |outstanding posted transactions or |
> + | | |completions and then disables the |
> + | | |Peripheral Channel via a write to |
> + | | |the Slave's Configuration Register. |
> + +----------------------+---------+---------------------------------------+
> + |HOST_RESET_ACK |Input |ACK for the HOST_RESET_WARN message |
> + +----------------------+---------+---------------------------------------+
> + |OOB_RESET_WARN |Output |Sent from the MC just before the OOB |
> + | | |processor is about to enter reset. Upon|
> + | | |receiving, the BMC must flush and |
> + | | |quiesce its OOB Channel upstream |
> + | | |request queues and assert OOB_RESET_ACK|
> + | | |VWire. The-MC subsequently completes |
> + | | |any outstanding posted transactions or |
> + | | |completions and then disables the OOB |
> + | | |Channel via a write to the Slave's |
> + | | |Configuration Register. |
> + +----------------------+---------+---------------------------------------+
> + |OOB_RESET_ACK |Input |ACK for OOB_RESET_WARN message |
> + +----------------------+---------+---------------------------------------+
> +
> +`Intel C620 Series Chipset Platform Controller Hub
> +<https://www.intel.com/content/www/us/en/chipsets/c620-series-chipset-datasheet.html>`_
> +
> + -- 17. Enhanced Serial Peripheral Interface
What is this line for? "17."?
> +
> +
> +`Enhanced Serial Peripheral Interface (eSPI)
> +- Interface Base Specification (for Client and Server Platforms)
> +<https://www.intel.com/content/dam/support/us/en/documents/software/chipset-software/327432-004_espi_base_specification_rev1.0.pdf>`_
> +
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 03605f8..cf3e7a1 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -472,6 +472,14 @@ config VEXPRESS_SYSCFG
> bus. System Configuration interface is one of the possible means
> of generating transactions on this bus.
>
> +config ASPEED_ESPI_SLAVE
> + depends on ARCH_ASPEED || COMPILE_TEST
> + depends on REGMAP_MMIO
> + tristate "Aspeed ast2500 eSPI slave device driver"
> + ---help---
> + Control Aspeed ast2500 eSPI slave controller to handle event
> + which needs the firmware's processing.
No module name and all that here?
thanks,
greg k-h
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