Hi Simon,
On Thu, Jan 29, 2015 at 2:04 AM, Simon Glass sjg@chromium.org wrote:
Hi Bin,
On 28 January 2015 at 07:19, Bin Meng bmeng.cn@gmail.com wrote:
In the Quark SoC, some chipset commands are accomplished by utilizing the internal message network within the host bridge (D0:F0). Accesses to this network are accomplished by populating the message control register (MCR), Message Control Register eXtension (MCRX) and the message data register (MDR).
Signed-off-by: Bin Meng bmeng.cn@gmail.com
arch/x86/cpu/quark/msg_port.c | 76 ++++++++++++++++++++++++ arch/x86/include/asm/arch-quark/msg_port.h | 93 ++++++++++++++++++++++++++++++ 2 files changed, 169 insertions(+) create mode 100644 arch/x86/cpu/quark/msg_port.c create mode 100644 arch/x86/include/asm/arch-quark/msg_port.h
diff --git a/arch/x86/cpu/quark/msg_port.c b/arch/x86/cpu/quark/msg_port.c new file mode 100644 index 0000000..a04462f --- /dev/null +++ b/arch/x86/cpu/quark/msg_port.c @@ -0,0 +1,76 @@ +/*
- Copyright (C) 2015, Bin Meng bmeng.cn@gmail.com
- SPDX-License-Identifier: GPL-2.0+
- */
+#include <common.h> +#include <pci.h> +#include <asm/arch/device.h> +#include <asm/arch/msg_port.h>
+u32 msg_port_read(u8 port, u32 reg) +{
u32 value;pci_write_config_dword(QUARK_HOST_BRIDGE, MSG_CTRL_EXT_REG,reg & 0xffffff00);pci_write_config_dword(QUARK_HOST_BRIDGE, MSG_CTRL_REG,MCR_FILL(MSG_OP_READ, port, reg));pci_read_config_dword(QUARK_HOST_BRIDGE, MSG_DATA_REG, &value);return value;Interesting - so this uses PCI config space? Does writing to the CTRL_REG actually cause anything to happen?
The message port registers are indirectly accessed via 3 registers in PCI configuration space, something like accessing PCI configuration space register, but they are not within PCI configuration space. So this is a two-level indirect access (first pci, then msg).
Could we remove the CTRL write with a function, like
void msg_port_setup(int op, int port, int reg) { pci_write_config_dword(QUARK_HOST_BRIDGE, MSG_CTRL_REG, (((op) << 24) | ((port) << 16) | (((reg) << 8) & 0xff00) | 0xf0)); }
then we can remove MCR_FILL.
Yes.
[snip]
Regards, Bin