Re: [PATCH v6 2/8] i3c: master: split bus_init callback into bus_init and master_set_info

[Boris Brezillon]

On Fri, 17 Apr 2020 18:20:52 +0200
Parshuram Thombare <pthombar@xxxxxxxxxxx> wrote:

> To support mastership handover procedure, this patch splits the
> bus_init callback into bus_init and master_set_info callbacks

Missing period at the end of this sentence.

IIRC, we discussed passing master info directly at controller
registration time for primary master registration, thus avoiding this
->master_set_info() step. Any good reason for doing that? I mean, I'd
expect the PID, BCR, DCR to be fixed, the only one that can be assigned
automatically is the address, and we can have a magic value for
'auto-assign the first available address', like '0'. The
write to DEV_ID_RR0() can be done conditionally in master_bus_init()
when '!secondary_master'.

> 
> Signed-off-by: Parshuram Thombare <pthombar@xxxxxxxxxxx>
> ---
>  drivers/i3c/master.c                 | 10 +++--
>  drivers/i3c/master/dw-i3c-master.c   | 29 ++++++++-----
>  drivers/i3c/master/i3c-master-cdns.c | 63 ++++++++++++++++++----------
>  include/linux/i3c/master.h           |  7 +++-
>  4 files changed, 71 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 5f4bd52121fe..0ec332e45737 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -1716,6 +1716,10 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
>  	if (ret)
>  		goto err_detach_devs;
>  
> +	ret = master->ops->master_set_info(master);
> +	if (ret)
> +		goto err_detach_devs;
> +
>  	/*
>  	 * The master device should have been instantiated in ->bus_init(),
>  	 * complain if this was not the case.
> @@ -2378,9 +2382,9 @@ EXPORT_SYMBOL_GPL(i3c_generic_ibi_recycle_slot);
>  
>  static int i3c_master_check_ops(const struct i3c_master_controller_ops *ops)
>  {
> -	if (!ops || !ops->bus_init || !ops->priv_xfers ||
> -	    !ops->send_ccc_cmd || !ops->do_daa || !ops->i2c_xfers ||
> -	    !ops->i2c_funcs)
> +	if (!ops || !ops->bus_init || !ops->master_set_info ||
> +	    !ops->priv_xfers || !ops->send_ccc_cmd || !ops->do_daa ||
> +	    !ops->i2c_xfers || !ops->i2c_funcs)
>  		return -EINVAL;
>  
>  	if (ops->request_ibi &&
> diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
> index 1d83c97431c7..5c9a72d68fb8 100644
> --- a/drivers/i3c/master/dw-i3c-master.c
> +++ b/drivers/i3c/master/dw-i3c-master.c
> @@ -593,7 +593,6 @@ static int dw_i3c_master_bus_init(struct i3c_master_controller *m)
>  {
>  	struct dw_i3c_master *master = to_dw_i3c_master(m);
>  	struct i3c_bus *bus = i3c_master_get_bus(m);
> -	struct i3c_device_info info = { };
>  	u32 thld_ctrl;
>  	int ret;
>  
> @@ -624,6 +623,24 @@ static int dw_i3c_master_bus_init(struct i3c_master_controller *m)
>  	writel(INTR_MASTER_MASK, master->regs + INTR_STATUS_EN);
>  	writel(INTR_MASTER_MASK, master->regs + INTR_SIGNAL_EN);
>  
> +	writel(IBI_REQ_REJECT_ALL, master->regs + IBI_SIR_REQ_REJECT);
> +	writel(IBI_REQ_REJECT_ALL, master->regs + IBI_MR_REQ_REJECT);
> +
> +	/* For now don't support Hot-Join */
> +	writel(readl(master->regs + DEVICE_CTRL) | DEV_CTRL_HOT_JOIN_NACK,
> +	       master->regs + DEVICE_CTRL);
> +
> +	dw_i3c_master_enable(master);
> +
> +	return 0;
> +}
> +
> +static int dw_i3c_master_set_info(struct i3c_master_controller *m)
> +{
> +	struct dw_i3c_master *master = to_dw_i3c_master(m);
> +	struct i3c_device_info info = { };
> +	int ret;
> +
>  	ret = i3c_master_get_free_addr(m, 0);
>  	if (ret < 0)
>  		return ret;
> @@ -638,15 +655,6 @@ static int dw_i3c_master_bus_init(struct i3c_master_controller *m)
>  	if (ret)
>  		return ret;
>  
> -	writel(IBI_REQ_REJECT_ALL, master->regs + IBI_SIR_REQ_REJECT);
> -	writel(IBI_REQ_REJECT_ALL, master->regs + IBI_MR_REQ_REJECT);
> -
> -	/* For now don't support Hot-Join */
> -	writel(readl(master->regs + DEVICE_CTRL) | DEV_CTRL_HOT_JOIN_NACK,
> -	       master->regs + DEVICE_CTRL);
> -
> -	dw_i3c_master_enable(master);
> -
>  	return 0;
>  }
>  
> @@ -1088,6 +1096,7 @@ static irqreturn_t dw_i3c_master_irq_handler(int irq, void *dev_id)
>  
>  static const struct i3c_master_controller_ops dw_mipi_i3c_ops = {
>  	.bus_init = dw_i3c_master_bus_init,
> +	.master_set_info = dw_i3c_master_set_info,
>  	.bus_cleanup = dw_i3c_master_bus_cleanup,
>  	.attach_i3c_dev = dw_i3c_master_attach_i3c_dev,
>  	.reattach_i3c_dev = dw_i3c_master_reattach_i3c_dev,
> diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
> index 8889a4fdb454..c2d1631a9e38 100644
> --- a/drivers/i3c/master/i3c-master-cdns.c
> +++ b/drivers/i3c/master/i3c-master-cdns.c
> @@ -1199,21 +1199,20 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
>  	struct cdns_i3c_master *master = to_cdns_i3c_master(m);
>  	unsigned long pres_step, sysclk_rate, max_i2cfreq;
>  	struct i3c_bus *bus = i3c_master_get_bus(m);
> -	u32 ctrl, prescl0, prescl1, pres, low;
> -	struct i3c_device_info info = { };
> -	int ret, ncycles;
> +	u32 ctrl, prescl0, prescl1, pres, low, bus_mode;
> +	int ncycles;
>  
>  	switch (bus->mode) {
>  	case I3C_BUS_MODE_PURE:
> -		ctrl = CTRL_PURE_BUS_MODE;
> +		bus_mode = CTRL_PURE_BUS_MODE;
>  		break;
>  
>  	case I3C_BUS_MODE_MIXED_FAST:
> -		ctrl = CTRL_MIXED_FAST_BUS_MODE;
> +		bus_mode = CTRL_MIXED_FAST_BUS_MODE;
>  		break;
>  
>  	case I3C_BUS_MODE_MIXED_SLOW:
> -		ctrl = CTRL_MIXED_SLOW_BUS_MODE;
> +		bus_mode = CTRL_MIXED_SLOW_BUS_MODE;
>  		break;
>  
>  	default:
> @@ -1244,7 +1243,6 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
>  	bus->scl_rate.i2c = sysclk_rate / ((pres + 1) * 5);
>  
>  	prescl0 |= PRESCL_CTRL0_I2C(pres);
> -	writel(prescl0, master->regs + PRESCL_CTRL0);
>  
>  	/* Calculate OD and PP low. */
>  	pres_step = 1000000000 / (bus->scl_rate.i3c * 4);
> @@ -1252,15 +1250,43 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
>  	if (ncycles < 0)
>  		ncycles = 0;
>  	prescl1 = PRESCL_CTRL1_OD_LOW(ncycles);
> +
> +	ctrl = readl(master->regs + CTRL);
> +	if (ctrl & CTRL_DEV_EN)
> +		cdns_i3c_master_disable(master);
> +	writel(prescl0, master->regs + PRESCL_CTRL0);
>  	writel(prescl1, master->regs + PRESCL_CTRL1);
> +	ctrl &= ~CTRL_BUS_MODE_MASK;
> +	ctrl |= bus_mode | CTRL_HALT_EN | CTRL_MCS_EN;
> +	/*
> +	 * Enable Hot-Join, and, when a Hot-Join request happens,
> +	 * disable all events coming from this device.
> +	 * We will issue ENTDAA afterwards from the threaded IRQ
> +	 * handler.
> +	 */
> +	if (!m->secondary)
> +		ctrl |= CTRL_HJ_ACK | CTRL_HJ_DISEC;
> +	writel(ctrl, master->regs + CTRL);
> +	cdns_i3c_master_enable(master);
>  
> -	/* Get an address for the master. */
> -	ret = i3c_master_get_free_addr(m, 0);
> -	if (ret < 0)
> -		return ret;
> +	return 0;
> +}
>  
> -	writel(prepare_rr0_dev_address(ret) | DEV_ID_RR0_IS_I3C,
> -	       master->regs + DEV_ID_RR0(0));
> +static int cdns_i3c_master_set_info(struct i3c_master_controller *m)
> +{
> +	struct cdns_i3c_master *master = to_cdns_i3c_master(m);
> +	struct i3c_device_info info = { };
> +	int ret;
> +
> +	if (!m->secondary) {
> +		/* Get an address for the master. */
> +		ret = i3c_master_get_free_addr(m, 0);
> +		if (ret < 0)
> +			return ret;
> +
> +		writel(prepare_rr0_dev_address(ret) | DEV_ID_RR0_IS_I3C,
> +		       master->regs + DEV_ID_RR0(0));
> +	}
>  
>  	cdns_i3c_master_dev_rr_to_info(master, 0, &info);
>  	if (info.bcr & I3C_BCR_HDR_CAP)
> @@ -1270,16 +1296,6 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
>  	if (ret)
>  		return ret;
>  
> -	/*
> -	 * Enable Hot-Join, and, when a Hot-Join request happens, disable all
> -	 * events coming from this device.
> -	 *
> -	 * We will issue ENTDAA afterwards from the threaded IRQ handler.
> -	 */
> -	ctrl |= CTRL_HJ_ACK | CTRL_HJ_DISEC | CTRL_HALT_EN | CTRL_MCS_EN;
> -	writel(ctrl, master->regs + CTRL);
> -
> -	cdns_i3c_master_enable(master);
>  
>  	return 0;
>  }
> @@ -1507,6 +1523,7 @@ static void cdns_i3c_master_recycle_ibi_slot(struct i3c_dev_desc *dev,
>  
>  static const struct i3c_master_controller_ops cdns_i3c_master_ops = {
>  	.bus_init = cdns_i3c_master_bus_init,
> +	.master_set_info = cdns_i3c_master_set_info,
>  	.bus_cleanup = cdns_i3c_master_bus_cleanup,
>  	.do_daa = cdns_i3c_master_do_daa,
>  	.attach_i3c_dev = cdns_i3c_master_attach_i3c_dev,
> diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> index f13fd8b1dd79..3dc7eafe811a 100644
> --- a/include/linux/i3c/master.h
> +++ b/include/linux/i3c/master.h
> @@ -337,10 +337,12 @@ struct i3c_bus {
>  
>  /**
>   * struct i3c_master_controller_ops - I3C master methods
> - * @bus_init: hook responsible for the I3C bus initialization. You should at
> - *	      least call master_set_info() from there and set the bus mode.
> + * @bus_init: hook responsible for the I3C bus initialization.
>   *	      You can also put controller specific initialization in there.
>   *	      This method is mandatory.
> + * @master_set_info: hook responsible for assigning address to main master.
> + *			You should call i3c_master_set_info from here.
> + *			This method is mandatory.
>   * @bus_cleanup: cleanup everything done in
>   *		 &i3c_master_controller_ops->bus_init().
>   *		 This method is optional.
> @@ -421,6 +423,7 @@ struct i3c_bus {
>   */
>  struct i3c_master_controller_ops {
>  	int (*bus_init)(struct i3c_master_controller *master);
> +	int (*master_set_info)(struct i3c_master_controller *m);
>  	void (*bus_cleanup)(struct i3c_master_controller *master);
>  	int (*attach_i3c_dev)(struct i3c_dev_desc *dev);
>  	int (*reattach_i3c_dev)(struct i3c_dev_desc *dev, u8 old_dyn_addr);