Message-ID: <b5f36260-8615-4b81-9905-a44d05e919a3@microchip.com>
Date: Fri, 22 Aug 2025 04:41:48 +0000
From: <Parthiban.Veerasooran@...rochip.com>
To: <dong100@...se.com>, <andrew+netdev@...n.ch>, <davem@...emloft.net>,
	<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
	<horms@...nel.org>, <corbet@....net>, <gur.stavi@...wei.com>,
	<maddy@...ux.ibm.com>, <mpe@...erman.id.au>, <danishanwar@...com>,
	<lee@...ger.us>, <gongfan1@...wei.com>, <lorenzo@...nel.org>,
	<geert+renesas@...der.be>, <lukas.bulwahn@...hat.com>,
	<alexanderduyck@...com>, <richardcochran@...il.com>, <kees@...nel.org>,
	<gustavoars@...nel.org>
CC: <netdev@...r.kernel.org>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-hardening@...r.kernel.org>
Subject: Re: [PATCH net-next v7 3/5] net: rnpgbe: Add basic mbx ops support

On 22/08/25 8:04 am, Dong Yibo wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Initialize basic mbx function.
> 
> Signed-off-by: Dong Yibo <dong100@...se.com>
> ---
>   drivers/net/ethernet/mucse/rnpgbe/Makefile    |   3 +-
>   drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h    |  17 +
>   .../net/ethernet/mucse/rnpgbe/rnpgbe_chip.c   |   3 +
>   .../net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c    | 395 ++++++++++++++++++
>   .../net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h    |  25 ++
>   5 files changed, 442 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c
>   create mode 100644 drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h
> 
> diff --git a/drivers/net/ethernet/mucse/rnpgbe/Makefile b/drivers/net/ethernet/mucse/rnpgbe/Makefile
> index 42c359f459d9..5fc878ada4b1 100644
> --- a/drivers/net/ethernet/mucse/rnpgbe/Makefile
> +++ b/drivers/net/ethernet/mucse/rnpgbe/Makefile
> @@ -6,4 +6,5 @@
> 
>   obj-$(CONFIG_MGBE) += rnpgbe.o
>   rnpgbe-objs := rnpgbe_main.o\
> -              rnpgbe_chip.o
> +              rnpgbe_chip.o\
> +              rnpgbe_mbx.o
> diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h
> index 9a86e67d6395..67e28a4667e7 100644
> --- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h
> +++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h
> @@ -5,6 +5,7 @@
>   #define _RNPGBE_H
> 
>   #include <linux/types.h>
> +#include <linux/mutex.h>
> 
>   extern const struct rnpgbe_info rnpgbe_n500_info;
>   extern const struct rnpgbe_info rnpgbe_n210_info;
> @@ -23,7 +24,23 @@ enum rnpgbe_hw_type {
>          rnpgbe_hw_unknown
>   };
> 
> +struct mucse_mbx_stats {
> +       u32 msgs_tx;
> +       u32 msgs_rx;
> +       u32 acks;
> +       u32 reqs;
> +};
> +
>   struct mucse_mbx_info {
> +       struct mucse_mbx_stats stats;
> +       u32 timeout;
> +       u32 usec_delay;
> +       u16 size;
> +       u16 fw_req;
> +       u16 fw_ack;
> +       /* lock for only one use mbx */
> +       struct mutex lock;
> +       bool irq_enabled;
>          /* fw <--> pf mbx */
>          u32 fw_pf_shm_base;
>          u32 pf2fw_mbox_ctrl;
> diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c
> index 179621ea09f3..f38daef752a3 100644
> --- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c
> +++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c
> @@ -1,8 +1,11 @@
>   // SPDX-License-Identifier: GPL-2.0
>   /* Copyright(c) 2020 - 2025 Mucse Corporation. */
> 
> +#include <linux/string.h>
> +
>   #include "rnpgbe.h"
>   #include "rnpgbe_hw.h"
> +#include "rnpgbe_mbx.h"
> 
>   /**
>    * rnpgbe_init_common - Setup common attribute
> diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c
> new file mode 100644
> index 000000000000..e02563b994c2
> --- /dev/null
> +++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c
> @@ -0,0 +1,395 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright(c) 2022 - 2025 Mucse Corporation. */
> +
> +#include <linux/pci.h>
> +#include <linux/errno.h>
> +#include <linux/delay.h>
> +#include <linux/iopoll.h>
> +
> +#include "rnpgbe.h"
> +#include "rnpgbe_mbx.h"
> +#include "rnpgbe_hw.h"
> +
> +/**
> + * mbx_data_rd32  - Reads reg with base mbx->fw_pf_shm_base
> + * @mbx: pointer to the MBX structure
> + * @reg: register offset
> + *
> + * @return: register value
> + **/
> +static u32 mbx_data_rd32(struct mucse_mbx_info *mbx, u32 reg)
> +{
> +       struct mucse_hw *hw = container_of(mbx, struct mucse_hw, mbx);
> +
> +       return readl(hw->hw_addr + mbx->fw_pf_shm_base + reg);
> +}
> +
> +/**
> + * mbx_data_wr32  - Writes value to reg with base mbx->fw_pf_shm_base
> + * @mbx: pointer to the MBX structure
> + * @reg: register offset
> + * @value: value to be written
> + *
> + **/
> +static void mbx_data_wr32(struct mucse_mbx_info *mbx, u32 reg, u32 value)
> +{
> +       struct mucse_hw *hw = container_of(mbx, struct mucse_hw, mbx);
> +
> +       writel(value, hw->hw_addr + mbx->fw_pf_shm_base + reg);
> +}
> +
> +/**
> + * mbx_ctrl_rd32  - Reads reg with base mbx->fw2pf_mbox_vec
> + * @mbx: pointer to the MBX structure
> + * @reg: register offset
> + *
> + * @return: register value
> + **/
> +static u32 mbx_ctrl_rd32(struct mucse_mbx_info *mbx, u32 reg)
> +{
> +       struct mucse_hw *hw = container_of(mbx, struct mucse_hw, mbx);
> +
> +       return readl(hw->hw_addr + mbx->fw2pf_mbox_vec + reg);
> +}
> +
> +/**
> + * mbx_ctrl_wr32  - Writes value to reg with base mbx->fw2pf_mbox_vec
> + * @mbx: pointer to the MBX structure
> + * @reg: register offset
> + * @value: value to be written
> + *
> + **/
> +static void mbx_ctrl_wr32(struct mucse_mbx_info *mbx, u32 reg, u32 value)
> +{
> +       struct mucse_hw *hw = container_of(mbx, struct mucse_hw, mbx);
> +
> +       writel(value, hw->hw_addr + mbx->fw2pf_mbox_vec + reg);
> +}
> +
> +/**
> + * mucse_mbx_get_fwreq - Read fw req from reg
> + * @mbx: pointer to the mbx structure
> + *
> + * @return: the req value
> + **/
> +static u16 mucse_mbx_get_fwreq(struct mucse_mbx_info *mbx)
> +{
> +       return mbx_data_rd32(mbx, MBX_FW2PF_COUNTER) & GENMASK_U32(15, 0);
> +}
> +
> +/**
> + * mucse_mbx_get_fwack - Read fw ack from reg
> + * @mbx: pointer to the MBX structure
> + *
> + * @return: the ack value
> + **/
> +static u16 mucse_mbx_get_fwack(struct mucse_mbx_info *mbx)
> +{
> +       return (mbx_data_rd32(mbx, MBX_FW2PF_COUNTER) >> 16);
> +}
> +
> +/**
> + * mucse_mbx_inc_pf_req - Increase req
> + * @hw: pointer to the HW structure
> + *
> + * mucse_mbx_inc_pf_req read pf_req from hw, then write
> + * new value back after increase
> + **/
> +static void mucse_mbx_inc_pf_req(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       u16 req;
> +       u32 v;
> +
> +       v = mbx_data_rd32(mbx, MBX_PF2FW_COUNTER);
> +       req = (v & GENMASK_U32(15, 0));
> +       req++;
> +       v &= GENMASK_U32(31, 16);
> +       v |= req;
> +       mbx_data_wr32(mbx, MBX_PF2FW_COUNTER, v);
> +       hw->mbx.stats.msgs_tx++;
> +}
> +
> +/**
> + * mucse_mbx_inc_pf_ack - Increase ack
> + * @hw: pointer to the HW structure
> + *
> + * mucse_mbx_inc_pf_ack read pf_ack from hw, then write
> + * new value back after increase
> + **/
> +static void mucse_mbx_inc_pf_ack(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       u16 ack;
> +       u32 v;
> +
> +       v = mbx_data_rd32(mbx, MBX_PF2FW_COUNTER);
> +       ack = (v >> 16) & GENMASK_U32(15, 0);
> +       ack++;
> +       v &= GENMASK_U32(15, 0);
> +       v |= (ack << 16);
> +       mbx_data_wr32(mbx, MBX_PF2FW_COUNTER, v);
> +       hw->mbx.stats.msgs_rx++;
> +}
> +
> +/**
> + * mucse_check_for_msg_pf - Check to see if the fw has sent mail
> + * @hw: pointer to the HW structure
> + *
> + * @return: 0 if the fw has set the Status bit or else
> + * -EIO
> + **/
> +static int mucse_check_for_msg_pf(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       u16 hw_req_count = 0;
I don't think you need to assign 0 here as this variable is updated in 
the next line.

Best regards,
Parthiban V
> +
> +       hw_req_count = mucse_mbx_get_fwreq(mbx);
> +       /* chip's register is reset to 0 when rc send reset
> +        * mbx command. This causes 'hw_req_count != hw->mbx.fw_req'
> +        * be TRUE before fw really reply. Driver must wait fw reset
> +        * done reply before using chip, we must check no-zero.
> +        **/
> +       if (hw_req_count != 0 && hw_req_count != hw->mbx.fw_req) {
> +               hw->mbx.stats.reqs++;
> +               return 0;
> +       }
> +
> +       return -EIO;
> +}
> +
> +/**
> + * mucse_poll_for_msg - Wait for message notification
> + * @hw: pointer to the HW structure
> + *
> + * @return: 0 on success, negative on failure
> + **/
> +static int mucse_poll_for_msg(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       int countdown = mbx->timeout;
> +       int val;
> +
> +       return read_poll_timeout(mucse_check_for_msg_pf,
> +                                val, val == 0, mbx->usec_delay,
> +                                countdown * mbx->usec_delay,
> +                                false, hw);
> +}
> +
> +/**
> + * mucse_check_for_ack_pf - Check to see if the VF has ACKed
> + * @hw: pointer to the HW structure
> + *
> + * @return: 0 if the fw has set the Status bit or else
> + * -EIO
> + **/
> +static int mucse_check_for_ack_pf(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       u16 hw_fw_ack;
> +
> +       hw_fw_ack = mucse_mbx_get_fwack(mbx);
> +       /* chip's register is reset to 0 when rc send reset
> +        * mbx command. This causes 'hw_fw_ack != hw->mbx.fw_ack'
> +        * be TRUE before fw really reply. Driver must wait fw reset
> +        * done reply before using chip, we must check no-zero.
> +        **/
> +       if (hw_fw_ack != 0 && hw_fw_ack != hw->mbx.fw_ack) {
> +               hw->mbx.stats.acks++;
> +               return 0;
> +       }
> +
> +       return -EIO;
> +}
> +
> +/**
> + * mucse_poll_for_ack - Wait for message acknowledgment
> + * @hw: pointer to the HW structure
> + *
> + * @return: 0 if it successfully received a message acknowledgment
> + **/
> +static int mucse_poll_for_ack(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       int countdown = mbx->timeout;
> +       int val;
> +
> +       return read_poll_timeout(mucse_check_for_ack_pf,
> +                                val, val == 0, mbx->usec_delay,
> +                                countdown * mbx->usec_delay,
> +                                false, hw);
> +}
> +
> +/**
> + * mucse_obtain_mbx_lock_pf - Obtain mailbox lock
> + * @hw: pointer to the HW structure
> + *
> + * This function maybe used in an irq handler.
> + *
> + * @return: 0 if we obtained the mailbox lock
> + **/
> +static int mucse_obtain_mbx_lock_pf(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       int try_cnt = 5000;
> +       u32 reg;
> +
> +       reg = PF2FW_MBOX_CTRL(mbx);
> +       while (try_cnt-- > 0) {
> +               mbx_ctrl_wr32(mbx, reg, MBOX_PF_HOLD);
> +               /* force write back before check */
> +               wmb();
> +               if (mbx_ctrl_rd32(mbx, reg) & MBOX_PF_HOLD)
> +                       return 0;
> +               udelay(100);
> +       }
> +       return -EIO;
> +}
> +
> +/**
> + * mucse_read_mbx_pf - Read a message from the mailbox
> + * @hw: pointer to the HW structure
> + * @msg: the message buffer
> + * @size: length of buffer
> + *
> + * This function copies a message from the mailbox buffer to the caller's
> + * memory buffer. The presumption is that the caller knows that there was
> + * a message due to a fw request so no polling for message is needed.
> + *
> + * @return: 0 on success, negative on failure
> + **/
> +static int mucse_read_mbx_pf(struct mucse_hw *hw, u32 *msg, u16 size)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       int size_inwords = size / 4;
> +       u32 ctrl_reg;
> +       int ret;
> +       int i;
> +
> +       ctrl_reg = PF2FW_MBOX_CTRL(mbx);
> +
> +       ret = mucse_obtain_mbx_lock_pf(hw);
> +       if (ret)
> +               return ret;
> +       for (i = 0; i < size_inwords; i++)
> +               msg[i] = mbx_data_rd32(mbx, MBX_FW_PF_SHM_DATA + 4 * i);
> +       /* Hw need write data_reg at last */
> +       mbx_data_wr32(mbx, MBX_FW_PF_SHM_DATA, 0);
> +       hw->mbx.fw_req = mucse_mbx_get_fwreq(mbx);
> +       mucse_mbx_inc_pf_ack(hw);
> +       mbx_ctrl_wr32(mbx, ctrl_reg, 0);
> +
> +       return 0;
> +}
> +
> +/**
> + * mucse_read_posted_mbx - Wait for message notification and receive message
> + * @hw: pointer to the HW structure
> + * @msg: the message buffer
> + * @size: length of buffer
> + *
> + * @return: 0 if it successfully received a message notification and
> + * copied it into the receive buffer.
> + **/
> +int mucse_read_posted_mbx(struct mucse_hw *hw, u32 *msg, u16 size)
> +{
> +       int ret;
> +
> +       ret = mucse_poll_for_msg(hw);
> +       if (ret)
> +               return ret;
> +
> +       return mucse_read_mbx_pf(hw, msg, size);
> +}
> +
> +/**
> + * mucse_mbx_reset - Reset mbx info, sync info from regs
> + * @hw: pointer to the HW structure
> + *
> + * This function reset all mbx variables to default.
> + **/
> +static void mucse_mbx_reset(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       u32 v;
> +
> +       v = mbx_data_rd32(mbx, MBX_FW2PF_COUNTER);
> +       hw->mbx.fw_req = v & GENMASK_U32(15, 0);
> +       hw->mbx.fw_ack = (v >> 16) & GENMASK_U32(15, 0);
> +       mbx_ctrl_wr32(mbx, PF2FW_MBOX_CTRL(mbx), 0);
> +       mbx_ctrl_wr32(mbx, FW_PF_MBOX_MASK(mbx), GENMASK_U32(31, 16));
> +}
> +
> +/**
> + * mucse_init_mbx_params_pf - Set initial values for pf mailbox
> + * @hw: pointer to the HW structure
> + *
> + * Initializes the hw->mbx struct to correct values for pf mailbox
> + */
> +void mucse_init_mbx_params_pf(struct mucse_hw *hw)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +
> +       mbx->usec_delay = 100;
> +       mbx->timeout = (4 * USEC_PER_SEC) / mbx->usec_delay;
> +       mbx->stats.msgs_tx = 0;
> +       mbx->stats.msgs_rx = 0;
> +       mbx->stats.reqs = 0;
> +       mbx->stats.acks = 0;
> +       mbx->size = MUCSE_MAILBOX_BYTES;
> +       mutex_init(&mbx->lock);
> +       mucse_mbx_reset(hw);
> +}
> +
> +/**
> + * mucse_write_mbx_pf - Place a message in the mailbox
> + * @hw: pointer to the HW structure
> + * @msg: the message buffer
> + * @size: length of buffer
> + *
> + * This function maybe used in an irq handler.
> + *
> + * @return: 0 if it successfully copied message into the buffer
> + **/
> +int mucse_write_mbx_pf(struct mucse_hw *hw, u32 *msg, u16 size)
> +{
> +       struct mucse_mbx_info *mbx = &hw->mbx;
> +       int size_inwords = size / 4;
> +       u32 ctrl_reg;
> +       int ret;
> +       int i;
> +
> +       ctrl_reg = PF2FW_MBOX_CTRL(mbx);
> +       ret = mucse_obtain_mbx_lock_pf(hw);
> +       if (ret)
> +               return ret;
> +
> +       for (i = 0; i < size_inwords; i++)
> +               mbx_data_wr32(mbx, MBX_FW_PF_SHM_DATA + i * 4, msg[i]);
> +
> +       /* flush msg and acks as we are overwriting the message buffer */
> +       hw->mbx.fw_ack = mucse_mbx_get_fwack(mbx);
> +       mucse_mbx_inc_pf_req(hw);
> +       mbx_ctrl_wr32(mbx, ctrl_reg, MBOX_CTRL_REQ);
> +
> +       return 0;
> +}
> +
> +/**
> + * mucse_write_posted_mbx - Write a message to the mailbox, wait for ack
> + * @hw: pointer to the HW structure
> + * @msg: the message buffer
> + * @size: length of buffer
> + *
> + * @return: 0 if it successfully copied message into the buffer and
> + * received an ack to that message within delay * timeout period
> + **/
> +int mucse_write_posted_mbx(struct mucse_hw *hw, u32 *msg, u16 size)
> +{
> +       int ret;
> +
> +       ret = mucse_write_mbx_pf(hw, msg, size);
> +       if (ret)
> +               return ret;
> +       return mucse_poll_for_ack(hw);
> +}
> diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h
> new file mode 100644
> index 000000000000..110c1ee025ba
> --- /dev/null
> +++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h
> @@ -0,0 +1,25 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright(c) 2020 - 2025 Mucse Corporation. */
> +
> +#ifndef _RNPGBE_MBX_H
> +#define _RNPGBE_MBX_H
> +
> +#include "rnpgbe.h"
> +
> +#define MUCSE_MAILBOX_BYTES 56
> +#define MBX_FW2PF_COUNTER 0
> +#define MBX_PF2FW_COUNTER 4
> +#define MBX_FW_PF_SHM_DATA 8
> +#define FW2PF_MBOX_VEC 0
> +#define PF2FW_MBOX_CTRL(mbx) ((mbx)->pf2fw_mbox_ctrl)
> +#define FW_PF_MBOX_MASK(mbx) ((mbx)->fw_pf_mbox_mask)
> +#define MBOX_CTRL_REQ BIT(0)
> +#define MBOX_PF_HOLD BIT(3)
> +#define MBOX_IRQ_EN 0
> +#define MBOX_IRQ_DISABLE 1
> +
> +int mucse_write_mbx_pf(struct mucse_hw *hw, u32 *msg, u16 size);
> +int mucse_write_posted_mbx(struct mucse_hw *hw, u32 *msg, u16 size);
> +void mucse_init_mbx_params_pf(struct mucse_hw *hw);
> +int mucse_read_posted_mbx(struct mucse_hw *hw, u32 *msg, u16 size);
> +#endif /* _RNPGBE_MBX_H */
> --
> 2.25.1
> 

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