From: Mark Brown <broonie@kernel.org>
To: Krishna Yarlagadda <kyarlagadda@nvidia.com>
Cc: "robh+dt@kernel.org" <robh+dt@kernel.org>,
"peterhuewe@gmx.de" <peterhuewe@gmx.de>,
"jgg@ziepe.ca" <jgg@ziepe.ca>,
"jarkko@kernel.org" <jarkko@kernel.org>,
"krzysztof.kozlowski+dt@linaro.org"
<krzysztof.kozlowski+dt@linaro.org>,
"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Sowjanya Komatineni <skomatineni@nvidia.com>,
Laxman Dewangan <ldewangan@nvidia.com>
Subject: Re: [Patch V3 1/3] tpm_tis-spi: Support hardware wait polling
Date: Thu, 23 Feb 2023 18:43:13 +0000 [thread overview]
Message-ID: <Y/ezwaFCn5h86u6X@sirena.org.uk> (raw)
In-Reply-To: <DM4PR12MB57695DE127286D1DA436E804C3AB9@DM4PR12MB5769.namprd12.prod.outlook.com>
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On Thu, Feb 23, 2023 at 06:41:43PM +0000, Krishna Yarlagadda wrote:
> > > + spi_bus_lock(phy->spi_device->master);
> > > +
> > > + while (len) {
> > Why?
> TPM supports max 64B in single transaction. Loop to send rest of it.
No, why is there a bus lock?
> > > + spi_xfer[0].tx_buf = phy->iobuf;
> > > + spi_xfer[0].len = 1;
> > > + spi_message_add_tail(&spi_xfer[0], &m);
> > > +
> > > + spi_xfer[1].tx_buf = phy->iobuf + 1;
> > > + spi_xfer[1].len = 3;
> > > + spi_message_add_tail(&spi_xfer[1], &m);
> > Why would we make these two separate transfers?
> Tegra QSPI combined sequence requires cmd, addr and data in different
> transfers. This eliminates need for additional flag for combined sequence.
That needs some documentation, and we might need a flag to ensure the
core doesn't coalesce the transfers.
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next prev parent reply other threads:[~2023-02-23 18:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-23 16:26 [Patch V3 0/3] Tegra TPM driver with HW flow control Krishna Yarlagadda
2023-02-23 16:26 ` [Patch V3 1/3] tpm_tis-spi: Support hardware wait polling Krishna Yarlagadda
2023-02-23 17:18 ` Mark Brown
2023-02-23 18:41 ` Krishna Yarlagadda
2023-02-23 18:43 ` Mark Brown [this message]
2023-02-24 14:16 ` Krishna Yarlagadda
2023-02-24 15:51 ` Mark Brown
2023-02-24 16:21 ` Krishna Yarlagadda
2023-02-23 16:26 ` [Patch V3 2/3] spi: tegra210-quad: set half duplex flag Krishna Yarlagadda
2023-02-23 16:26 ` [Patch V3 3/3] spi: tegra210-quad: Enable TPM wait polling Krishna Yarlagadda
2023-02-23 17:28 ` Mark Brown
2023-02-23 18:46 ` Krishna Yarlagadda
2023-02-23 18:31 ` (subset) [Patch V3 0/3] Tegra TPM driver with HW flow control Mark Brown
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