linux-kernel - Re: [PATCH v4 01/10] i3c: Add core I3C infrastructure

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Date:   Mon, 4 Jun 2018 09:11:25 +0000
From:   Przemyslaw Gaj <pgaj@...ence.com>
To:     Boris Brezillon <boris.brezillon@...tlin.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>
CC:     Przemyslaw Sroka <psroka@...ence.com>,
        Arkadiusz Golec <agolec@...ence.com>,
        Alan Douglas <adouglas@...ence.com>,
        Bartosz Folta <bfolta@...ence.com>,
        Damian Kos <dkos@...ence.com>,
        Alicja Jurasik-Urbaniak <alicja@...ence.com>,
        Cyprian Wronka <cwronka@...ence.com>,
        Suresh Punnoose <sureshp@...ence.com>,
        Rafal Ciepiela <rafalc@...ence.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Nishanth Menon <nm@...com>, Rob Herring <robh+dt@...nel.org>,
        Pawel Moll <pawel.moll@....com>,
        Mark Rutland <mark.rutland@....com>,
        Ian Campbell <ijc+devicetree@...lion.org.uk>,
        Kumar Gala <galak@...eaurora.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Vitor Soares <Vitor.Soares@...opsys.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Xiang Lin <Xiang.Lin@...aptics.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>
Subject: Re: [PATCH v4 01/10] i3c: Add core I3C infrastructure

Hi Boris

It looks great, just one comment to DEFSLVS command:

On 6/4/18, 9:32 AM, "Boris Brezillon" <boris.brezillon@...tlin.com> wrote:

    +int i3c_master_defslvs_locked(struct i3c_master_controller *master)
    +{
    +	struct i3c_ccc_cmd_dest dest = {
    +		.addr = I3C_BROADCAST_ADDR,
    +	};
    +	struct i3c_ccc_cmd cmd = {
    +		.id = I3C_CCC_DEFSLVS,
    +		.dests = &dest,
    +		.ndests = 1,
    +	};
    +	struct i3c_ccc_defslvs *defslvs;
    +	struct i3c_ccc_dev_desc *desc;
    +	struct i3c_device *i3cdev;
    +	struct i2c_device *i2cdev;
    +	struct i3c_bus *bus;
    +	bool send = false;
    +	int ndevs = 0, ret;
    +
    +	if (!master)
    +		return -EINVAL;
    +
    +	bus = i3c_master_get_bus(master);
    +	i3c_bus_for_each_i3cdev(bus, i3cdev) {
    +		ndevs++;
    +		if (I3C_BCR_DEVICE_ROLE(i3cdev->info.bcr) == I3C_BCR_I3C_MASTER)
    +			send = true;
    +	}
    +
    +	/* No other master on the bus, skip DEFSLVS. */
    +	if (!send)
    +		return 0;
    +
    +	i3c_bus_for_each_i2cdev(bus, i2cdev)
    +		ndevs++;
    +
    +	dest.payload.len = sizeof(*defslvs) +
    +			   ((ndevs - 1) * sizeof(struct i3c_ccc_dev_desc));
    +	defslvs = kzalloc(dest.payload.len, GFP_KERNEL);
    +	if (!defslvs)
    +		return -ENOMEM;
    +
    +	dest.payload.data = defslvs;
    +
    +	defslvs->count = ndevs;
    +	defslvs->master.bcr = master->this->info.bcr;
    +	defslvs->master.dcr = master->this->info.dcr;
    +	defslvs->master.dyn_addr = master->this->info.dyn_addr;
    +	defslvs->master.static_addr = I3C_BROADCAST_ADDR;
    +
    +	desc = defslvs->slaves;
    +	i3c_bus_for_each_i2cdev(bus, i2cdev) {
    +		desc->lvr = i2cdev->lvr;
    +		desc->static_addr = i2cdev->info.addr;
    +		desc++;
    +	}
    +
    +	i3c_bus_for_each_i3cdev(bus, i3cdev) {
    +		/* Skip the I3C dev representing this master. */
    +		if (i3cdev == master->this)
    +			continue;
    +
    +		desc->bcr = i3cdev->info.bcr;
    +		desc->dcr = i3cdev->info.dcr;
    +		desc->dyn_addr = i3cdev->info.dyn_addr;
    +		desc->static_addr = i3cdev->info.static_addr;
    +		desc++;
    +	}
    +
    +	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    +	kfree(defslvs);
    +
    +	return ret;
    +}

You should shift all the addresses (dynamic and static) one bit left. 
Addresses are stored on bits [7:1], this is described in MIPI spec, 
section 5.1.9.3.7 Define List of Slaves (DEFSLVS)

Regards,
Przemyslaw Gaj