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Date:   Mon, 2 Dec 2019 12:20:50 +0000
From:   Andrew Murray <andrew.murray@arm.com>
To:     Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc:     maz@kernel.org, linux-kernel@vger.kernel.org,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Eric Anholt <eric@anholt.net>,
        Stefan Wahren <wahrenst@gmx.net>,
        Florian Fainelli <f.fainelli@gmail.com>,
        bcm-kernel-feedback-list@broadcom.com, james.quinlan@broadcom.com,
        mbrugger@suse.com, phil@raspberrypi.org, jeremy.linton@arm.com,
        linux-pci@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 5/7] PCI: brcmstb: add MSI capability
Message-ID: <20191202122050.GA18399@e119886-lin.cambridge.arm.com>
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On Mon, Dec 02, 2019 at 10:59:36AM +0100, Nicolas Saenz Julienne wrote:
> Hi Andrew,
> 
> On Fri, 2019-11-29 at 15:46 +0000, Andrew Murray wrote:
> > On Tue, Nov 26, 2019 at 10:19:43AM +0100, Nicolas Saenz Julienne wrote:
> > > From: Jim Quinlan <james.quinlan@broadcom.com>
> > > 
> > > This adds MSI support to the Broadcom STB PCIe host controller. The MSI
> > > controller is physically located within the PCIe block, however, there
> > > is no reason why the MSI controller could not be moved elsewhere in the
> > > future. MSIX is not supported by the HW.
> > > 
> > > Since the internal Brcmstb MSI controller is intertwined with the PCIe
> > > controller, it is not its own platform device but rather part of the
> > > PCIe platform device.
> > > 
> > > Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
> > > Co-developed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> > > Reviewed-by: Marc Zyngier <maz@kernel.org>
> > > 
> > > ---
> > > 
> > > Changes since v2 (kept Marc's Reviewed-by as changes didn't affect irq
> > > subsystem stuff or seem petty enough):
> > >   - Use standard APIs on register operations
> > >   - Get rid of revision code
> > 
> > Do any RPI4's have a HW revision of less than 33?
> 
> No, IIRC it's actually revision 34. I had left that bit of code in, following
> the same train of thought as with the of_data on the device-tree part of the
> driver: "It's harmless and should make accomodating other devices easier." It
> turned out not to be such a great approach. Lesson's learned. So I decided to
> remove it.

OK you can add my:

Reviewed-by: Andrew Murray <andrew.murray@arm.com>

Thanks,

Andrew Murray

> 
> > >   - Update rules to msi_target_addr selection
> > >   - Remove unwarranted MSI_FLAG_PCI_MSIX
> > >   - Small cosmetic changes
> > > 
> > > Changes since v1:cuando ten?as tu vacaciones?
> > >   - Move revision code and some registers to this patch
> > >   - Use PCIE_MSI_IRQ_DOMAIN in Kconfig
> > >   - Remove redundant register read from ISR
> > >   - Fail probe on MSI init error
> > >   - Get rid of msi_internal
> > >   - Use bitmap family of functions
> > >   - Use edge triggered setup
> > >   - Add comment regarding MultiMSI
> > >   - Simplify compose_msi_msg to avoid reg read
> > > 
> > > This is based on Jim's original submission[1] with some slight changes
> > > regarding how pcie->msi_target_addr is decided.
> > > 
> > > [1] https://patchwork.kernel.org/patch/10605955/
> > > 
> > >  drivers/pci/controller/Kconfig        |   1 +
> > >  drivers/pci/controller/pcie-brcmstb.c | 261 +++++++++++++++++++++++++-
> > >  2 files changed, 261 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> > > index 27504f108ee5..918e283bbff1 100644
> > > +
> > > +static void brcm_msi_compose_msi_msg(struct irq_data *data, struct msi_msg
> > > *msg)
> > > +{
> > > +	struct brcm_msi *msi = irq_data_get_irq_chip_data(data);
> > > +
> > > +	msg->address_lo = lower_32_bits(msi->target_addr);
> > > +	msg->address_hi = upper_32_bits(msi->target_addr);
> > > +	msg->data = 0x6540 | data->hwirq;
> > 
> > NIT: Perhaps this 0x6540 can be a define - just in the same way we have a
> > define
> > for PCIE_MISC_MSI_DATA_CONFIG_VAL.
> 
> Noted
> 
> Regards,
> Nicolas
>