linux-kernel - Re: [PATCH v2 2/2] i3c: dw-i3c-master: fix SIR reject bit mapping for dynamic addresses

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Message-ID: <aXOdDgLT97N9MrJj@lizhi-Precision-Tower-5810>
Date: Fri, 23 Jan 2026 11:08:46 -0500
From: Frank Li <Frank.li@....com>
To: adrianhoyin.ng@...era.com
Cc: alexandre.belloni@...tlin.com, linux-i3c@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] i3c: dw-i3c-master: fix SIR reject bit mapping
 for dynamic addresses

On Fri, Jan 23, 2026 at 03:35:12PM +0800, adrianhoyin.ng@...era.com wrote:
> From: Adrian Ng Ho Yin <adrianhoyin.ng@...era.com>
>
> The IBI_SIR_REQ_REJECT register is a 32-bit bitmap indexed by the
> dynamic address of each I3C slave. The DesignWare controller derives
> the bit index by folding the 7-bit dynamic address into a 5-bit value,
> using the sum of the lower 5 bits and the upper 2 bits, modulo 32.
>
> The current implementation incorrectly uses the device table index
> when updating the SIR reject mask, which can result in rejecting or
> accepting IBIs for the wrong device.
>
> Compute the SIR reject bit index directly from the dynamic address,
> as defined by the controller specification, and use it consistently
> when updating the reject mask.
>
> Signed-off-by: Adrian Ng Ho Yin <adrianhoyin.ng@...era.com>
> ---
>  drivers/i3c/master/dw-i3c-master.c | 26 ++++++++++++++++++++++++--
>  1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
> index 15101f41b9e6..ffb1edd32097 100644
> --- a/drivers/i3c/master/dw-i3c-master.c
> +++ b/drivers/i3c/master/dw-i3c-master.c
> @@ -205,6 +205,11 @@
>  #define EXTENDED_CAPABILITY		0xe8
>  #define SLAVE_CONFIG			0xec
>
> +#define DYN_ADDR_LO_BITS		5
> +#define DYN_ADDR_LO_MASK GENMASK(4, 0)
> +#define DYN_ADDR_HI_MASK GENMASK(6, 5)
> +#define IBI_SIR_BIT_MOD 32       /* 32-bit vector */
> +
>  #define DW_I3C_DEV_NACK_RETRY_CNT_MAX	0x3
>  #define DEV_ADDR_TABLE_DEV_NACK_RETRY_MASK   GENMASK(30, 29)
>  #define DEV_ADDR_TABLE_DYNAMIC_MASK		GENMASK(23, 16)
> @@ -217,6 +222,7 @@
>  #define DEV_ADDR_TABLE_DYNAMIC_ADDR(x) FIELD_PREP(DEV_ADDR_TABLE_DYNAMIC_MASK, x)
>  #define DEV_ADDR_TABLE_STATIC_ADDR(x) FIELD_PREP(DEV_ADDR_TABLE_STATIC_MASK, x)
>  #define DEV_ADDR_TABLE_LOC(start, idx)	((start) + ((idx) << 2))
> +#define DEV_ADDR_TABLE_GET_DYNAMIC_ADDR(x) FIELD_GET(DEV_ADDR_TABLE_DYNAMIC_MASK, x)
>
>  #define I3C_BUS_SDR1_SCL_RATE		8000000
>  #define I3C_BUS_SDR2_SCL_RATE		6000000
> @@ -264,6 +270,14 @@ struct dw_i3c_drvdata {
>  	u32 flags;
>  };
>
> +static inline u32 get_ibi_sir_bit_index(u8 addr)
> +{
> +	u32 lo = addr & DYN_ADDR_LO_MASK;
> +	u32 hi = (addr & DYN_ADDR_HI_MASK) >> DYN_ADDR_LO_BITS;

Use GET_FIELD(), so needn't define DYN_ADDR_LO_BITS.

Frank
> +
> +	return (lo + hi) % IBI_SIR_BIT_MOD;
> +}
> +
>  static bool dw_i3c_master_supports_ccc_cmd(struct i3c_master_controller *m,
>  					   const struct i3c_ccc_cmd *cmd)
>  {
> @@ -1235,11 +1249,19 @@ static void dw_i3c_master_set_sir_enabled(struct dw_i3c_master *master,
>  {
>  	u32 dat_entry, reg;
>  	bool global;
> +	u8 dynamic_addr;
>
>  	dat_entry = DEV_ADDR_TABLE_LOC(master->datstartaddr, idx);
>
>  	guard(spinlock_irqsave)(&master->devs_lock);
>  	reg = readl(master->regs + dat_entry);
> +	dynamic_addr = DEV_ADDR_TABLE_GET_DYNAMIC_ADDR(reg);
> +
> +	if (!dynamic_addr)
> +		dev_warn(master->dev,
> +			 "<%s> unassigned slave device, dynamic addr:%x\n",
> +			 __func__, dynamic_addr);
> +
>  	if (enable) {
>  		reg &= ~DEV_ADDR_TABLE_SIR_REJECT;
>  		if (dev->info.bcr & I3C_BCR_IBI_PAYLOAD)
> @@ -1252,11 +1274,11 @@ static void dw_i3c_master_set_sir_enabled(struct dw_i3c_master *master,
>
>  	if (enable) {
>  		global = (master->sir_rej_mask == IBI_REQ_REJECT_ALL);
> -		master->sir_rej_mask &= ~BIT(idx);
> +		master->sir_rej_mask &= ~BIT(get_ibi_sir_bit_index(dynamic_addr));
>  	} else {
>  		bool hj_rejected = !!(readl(master->regs + DEVICE_CTRL) & DEV_CTRL_HOT_JOIN_NACK);
>
> -		master->sir_rej_mask |= BIT(idx);
> +		master->sir_rej_mask |= BIT(get_ibi_sir_bit_index(dynamic_addr));
>  		global = (master->sir_rej_mask == IBI_REQ_REJECT_ALL) && hj_rejected;
>  	}
>  	writel(master->sir_rej_mask, master->regs + IBI_SIR_REQ_REJECT);
> --
> 2.49.GIT
>