From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.poirier@linaro.org (Mathieu Poirier) Date: Tue, 20 Nov 2018 13:57:37 -0700 Subject: [RFC PATCH 1/3] drivers: amba: Updates to component identification for driver matching. In-Reply-To: <20181115012842.2353-2-mike.leach@linaro.org> References: <20181115012842.2353-1-mike.leach@linaro.org> <20181115012842.2353-2-mike.leach@linaro.org> Message-ID: <20181120205737.GA17267@xps15> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Mike, On Thu, Nov 15, 2018 at 01:28:40AM +0000, Mike Leach wrote: > The CoreSight specification (ARM IHI 0029E), updates the ID register > requirements for components on an AMBA bus, to cover both traditional > ARM Primecell type devices, and newer CoreSight and other components. > > The Peripheral ID (PID) / Component ID (CID) pair is extended in certain > cases to uniquely identify components. CoreSight components related to > a single function can share Peripheral ID values, and must be further > identified using a Unique Component Identifier (UCI). e.g. the ETM, CTI, > PMU and Debug hardware of the A35 all share the same PID. > > Bits 11:8 of the CID are defined to be the device class. > Class 0xF remains for PrimeCell and legacy components. > Class 0x9 defines the component as CoreSight (CORESIGHT_CID above) > Class 0x0, 0x1, 0xB, 0xE define components that do not have driver support > at present. > Class 0x2-0x8,0xA and 0xD-0xD are presently reserved. > > The specification futher defines which classes of device use the standard > CID/PID pair, and when additional ID registers are required. > > The patches provide an update of amba_device and matching code to handle > the additional registers required for the Class 0x9 (CoreSight) UCI. > The *data pointer in the amba_id is used by the driver to provide extended > ID register values for matching. > > CoreSight components where PID/CID pair is currently sufficient for > unique identification need not provide this additional information. > > Signed-off-by: Mike Leach > --- > drivers/amba/bus.c | 48 ++++++++++++++++++++++++++++++++++++---- > include/linux/amba/bus.h | 33 +++++++++++++++++++++++++++ > 2 files changed, 77 insertions(+), 4 deletions(-) > > diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c > index 41b706403ef7..6eab977f4314 100644 > --- a/drivers/amba/bus.c > +++ b/drivers/amba/bus.c > @@ -26,6 +26,28 @@ > > #define to_amba_driver(d) container_of(d, struct amba_driver, drv) > > +/* called on periphid match and class 0x9 coresight device. */ > +static int amba_uci_match(const struct amba_id *table, struct amba_device *dev) > +{ > + int ret = 0; > + struct amba_cs_uci_id *uci; > + > + uci = table->data; > + > + /* no table data - return match on periphid */ > + if (!uci) > + return 1; > + > + if (uci->devarch) { > + ret = (dev->uci.devtype == uci->devtype) && > + ((dev->uci.devarch & uci->mask) == uci->devarch); > + } else { > + /* devtype only if devarch set to 0 */ > + ret = dev->uci.devtype == uci->devtype; > + } > + return ret; > +} > + > static const struct amba_id * > amba_lookup(const struct amba_id *table, struct amba_device *dev) > { > @@ -33,11 +55,17 @@ amba_lookup(const struct amba_id *table, struct amba_device *dev) > > while (table->mask) { > ret = (dev->periphid & table->mask) == table->id; > - if (ret) > - break; > + /* matched on periphid - check UCI if CoreSight */ > + if (ret) { > + if (dev->cid == CORESIGHT_CID) { > + ret = amba_uci_match(table, dev); > + if (ret) > + break; > + } else > + break; > + } > table++; > } > - Carefull with the line removal. > return ret ? table : NULL; > } > > @@ -399,10 +427,22 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent) > cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) << > (i * 8); > > + if (cid == CORESIGHT_CID) { > + /* set the base to the start of the last 4k block */ > + void __iomem *csbase = tmp + size - 4096; > + > + dev->uci.devarch = > + readl(csbase + UCI_REG_DEVARCH_OFFSET); > + dev->uci.devtype = > + readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff; Any reason for not masking @devarch the same way you're doing for @devtype? If we were to mask here we wouldn't have to carry the mask in struct amba_cs_uci_id and deal with it in amba_uci_match(). Russell King maintains AMBA. Please address your next revision to him and CC the rest of us, as specified by get_maintainer.pl. Thanks, Mathieu > + } > + > amba_put_disable_pclk(dev); > > - if (cid == AMBA_CID || cid == CORESIGHT_CID) > + if (cid == AMBA_CID || cid == CORESIGHT_CID) { > dev->periphid = pid; > + dev->cid = cid; > + } > > if (!dev->periphid) > ret = -ENODEV; > diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h > index d143c13bed26..a83a0a3dece8 100644 > --- a/include/linux/amba/bus.h > +++ b/include/linux/amba/bus.h > @@ -25,6 +25,36 @@ > #define AMBA_CID 0xb105f00d > #define CORESIGHT_CID 0xb105900d > > +/* > + * CoreSight Architecture specification updates the ID specification > + * for components on the AMBA bus. (ARM IHI 0029E) > + * > + * Bits 11:8 of the CID are the device class. > + * > + * Class 0xF remains for PrimeCell and legacy components. (AMBA_CID above) > + * Class 0x9 defines the component as CoreSight (CORESIGHT_CID above) > + * Class 0x0, 0x1, 0xB, 0xE define components that do not have driver support > + * at present. > + * Class 0x2-0x8,0xA and 0xD-0xD are presently reserved. > + * > + * Remaining CID bits stay as 0xb105-00d > + */ > + > +/* > + * Class 0x9 components use additional values to form a Unique Component > + * Identifier (UCI), where peripheral ID values are identical for different > + * components. Passed to the amba bus code from the component driver via > + * the amba_id->data pointer. > + */ > +struct amba_cs_uci_id { > + unsigned int devarch; > + unsigned int mask; > + unsigned int devtype; > +}; > + > +#define UCI_REG_DEVTYPE_OFFSET 0xFCC > +#define UCI_REG_DEVARCH_OFFSET 0xFBC > + > struct clk; > > struct amba_device { > @@ -32,6 +62,8 @@ struct amba_device { > struct resource res; > struct clk *pclk; > unsigned int periphid; > + unsigned int cid; > + struct amba_cs_uci_id uci; > unsigned int irq[AMBA_NR_IRQS]; > char *driver_override; > }; > @@ -61,6 +93,7 @@ enum amba_vendor { > (((conf) & 0xff) << 24 | ((rev) & 0xf) << 20 | \ > AMBA_VENDOR_LINUX << 12 | ((part) & 0xfff)) > > + > extern struct bus_type amba_bustype; > > #define to_amba_device(d) container_of(d, struct amba_device, dev) > -- > 2.19.1 >