On Fri, Dec 01, 2017 at 04:10:55PM -0600, Pierre-Louis Bossart wrote:
> On 12/1/17 3:56 AM, Vinod Koul wrote:
> >A Master registers with SoundWire bus and scans the firmware provided
>
> nitpick: is the 'register' correct? You create a bus instance for each
> hardware master interface. Or is my brain fried?
naah, thankfully it is not :)
I will reword this, I see it can cause ambguity :)
> >+int sdw_add_bus_master(struct sdw_bus *bus)
> >+{
> >+ int ret;
> >+
> >+ if (!bus->dev) {
> >+ pr_err("SoundWire bus has no device");
> >+ return -ENODEV;
> >+ }
> >+
> >+ mutex_init(&bus->bus_lock);
> >+ INIT_LIST_HEAD(&bus->slaves);
> >+
> >+ /*
> >+ * Device numbers in SoundWire are 0 thru 15 with 0 being
> >+ * Enumeration device number and 15 broadcast device number. So
> >+ * they are not used for assignment so mask these and other
> >+ * higher bits
>
> device 14 is used for the master and is not supported by these patches.
> While allowed, if you use device 12 and 13 (groups) you can't get the status
> information in a PING command so the recommendation is to avoid them.
> Those device numbers should never be used really (on top of 0 and 15 as
> explained above)
Yeah we should also exclude 12 thru 14 here. The group alllocation when done
need to do differently that this one, so will mask those too.
> >+void sdw_extract_slave_id(struct sdw_bus *bus,
> >+ u64 addr, struct sdw_slave_id *id)
> >+{
> >+ dev_dbg(bus->dev, "SDW Slave Addr: %llx", addr);
> >+
> >+ /*
> >+ * Spec definition
> >+ * Register Bit Contents
> >+ * DevId_0 [7:4] 47:44 sdw_version
> >+ * DevId_0 [3:0] 43:40 unique_id
> >+ * DevId_1 39:32 mfg_id [15:8]
> >+ * DevId_2 31:24 mfg_id [7:0]
>
> Add a reference to mid.mipi.org (here or in the summary) ?
Will add in summary, makes sense on that page
> >+int sdw_acpi_find_slaves(struct sdw_bus *bus)
> >+{
> >+ struct acpi_device *adev, *parent;
> >+
> >+ parent = ACPI_COMPANION(bus->dev);
> >+ if (!parent) {
> >+ dev_err(bus->dev, "Can't find parent for acpi bind\n");
> >+ return -ENODEV;
> >+ }
> >+
> >+ list_for_each_entry(adev, &parent->children, node) {
> >+ unsigned long long addr;
> >+ struct sdw_slave_id id;
> >+ unsigned int link_id;
> >+ acpi_status status;
> >+
> >+ status = acpi_evaluate_integer(adev->handle,
> >+ METHOD_NAME__ADR, NULL, &addr);
> >+
> >+ if (ACPI_FAILURE(status)) {
> >+ dev_err(bus->dev, "_ADR resolution failed: %x\n",
> >+ status);
> >+ return status;
> >+ }
> >+
> >+ /* Extract link id from ADR, it is from 48 to 51 bits */
>
> nitpick: in bits 51..48 as defined in the MIPI SoundWire DisCo spec.
ok
> >+/* SDW Enumeration Device Number */
> >+#define SDW_ENUM_DEV_NUM 0
>
> add
> SDW_GROUP12_DEV_NUM 12
> SDW_GROUP12_DEV_NUM 13
you mean SDW_GROUP13_DEV_NUM :D
> SDW_MASTER_DEV_NUM 14 /* not supported in these patches */
These dont help now as we dont support, so kind of dead code.
Lets add them when we really support it
--
~Vinod
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