From: Vignesh R <vigneshr@ti.com>
To: Mark Brown <broonie@kernel.org>
Cc: Tony Lindgren <tony@atomide.com>,
Michal Suchanek <hramrach@gmail.com>,
Russell King <linux@arm.linux.org.uk>,
<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-omap@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-mtd@lists.infradead.org>, <linux-spi@vger.kernel.org>
Subject: Re: [PATCH v2 2/5] spi: spi-ti-qspi: add mmap mode read support
Date: Thu, 5 Nov 2015 11:46:09 +0530 [thread overview]
Message-ID: <563AF429.1000406@ti.com> (raw)
In-Reply-To: <20151104144112.GJ1717@sirena.org.uk>
On 11/04/2015 08:11 PM, Mark Brown wrote:
> On Tue, Nov 03, 2015 at 03:36:11PM +0530, Vignesh R wrote:
>
>> + ti_qspi_enable_memory_map(spi);
>> + ti_qspi_setup_mmap_read(spi, read_opcode, addr_width,
>> + dummy_bytes);
>> + memcpy_fromio(buf, qspi->mmap_base + from, len);
>> + *retlen = len;
>> + ti_qspi_disable_memory_map(spi);
>
> We'll be constantly enabling and disabling memory mapping with this.
> I'm not sure that's a meaningful cost given that it doesn't actually
> remap anything but rather just switches hardware modes, we can always
> optimise it later if it is.
>
Hmm, I will move the ti_qspi_disable_memory_map() call to
ti_qspi_start_transfer_one(), so that mmap mode is disabled only when
normal SPI bus transfer is requested. Further, "mmap_enabled" status
flag can be used to determine whether mode switch is required or not.
This should help to overcome enabling and disabling memory mapping
between successive mmap read requests.
--
Regards
Vignesh
WARNING: multiple messages have this Message-ID (diff)
From: Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org>
To: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>,
Michal Suchanek
<hramrach-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v2 2/5] spi: spi-ti-qspi: add mmap mode read support
Date: Thu, 5 Nov 2015 11:46:09 +0530 [thread overview]
Message-ID: <563AF429.1000406@ti.com> (raw)
In-Reply-To: <20151104144112.GJ1717-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
On 11/04/2015 08:11 PM, Mark Brown wrote:
> On Tue, Nov 03, 2015 at 03:36:11PM +0530, Vignesh R wrote:
>
>> + ti_qspi_enable_memory_map(spi);
>> + ti_qspi_setup_mmap_read(spi, read_opcode, addr_width,
>> + dummy_bytes);
>> + memcpy_fromio(buf, qspi->mmap_base + from, len);
>> + *retlen = len;
>> + ti_qspi_disable_memory_map(spi);
>
> We'll be constantly enabling and disabling memory mapping with this.
> I'm not sure that's a meaningful cost given that it doesn't actually
> remap anything but rather just switches hardware modes, we can always
> optimise it later if it is.
>
Hmm, I will move the ti_qspi_disable_memory_map() call to
ti_qspi_start_transfer_one(), so that mmap mode is disabled only when
normal SPI bus transfer is requested. Further, "mmap_enabled" status
flag can be used to determine whether mode switch is required or not.
This should help to overcome enabling and disabling memory mapping
between successive mmap read requests.
--
Regards
Vignesh
--
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WARNING: multiple messages have this Message-ID (diff)
From: Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org>
To: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>,
Michal Suchanek
<hramrach-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>,
<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
<linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
<linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
<linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH v2 2/5] spi: spi-ti-qspi: add mmap mode read support
Date: Thu, 5 Nov 2015 11:46:09 +0530 [thread overview]
Message-ID: <563AF429.1000406@ti.com> (raw)
In-Reply-To: <20151104144112.GJ1717-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
On 11/04/2015 08:11 PM, Mark Brown wrote:
> On Tue, Nov 03, 2015 at 03:36:11PM +0530, Vignesh R wrote:
>
>> + ti_qspi_enable_memory_map(spi);
>> + ti_qspi_setup_mmap_read(spi, read_opcode, addr_width,
>> + dummy_bytes);
>> + memcpy_fromio(buf, qspi->mmap_base + from, len);
>> + *retlen = len;
>> + ti_qspi_disable_memory_map(spi);
>
> We'll be constantly enabling and disabling memory mapping with this.
> I'm not sure that's a meaningful cost given that it doesn't actually
> remap anything but rather just switches hardware modes, we can always
> optimise it later if it is.
>
Hmm, I will move the ti_qspi_disable_memory_map() call to
ti_qspi_start_transfer_one(), so that mmap mode is disabled only when
normal SPI bus transfer is requested. Further, "mmap_enabled" status
flag can be used to determine whether mode switch is required or not.
This should help to overcome enabling and disabling memory mapping
between successive mmap read requests.
--
Regards
Vignesh
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
WARNING: multiple messages have this Message-ID (diff)
From: vigneshr@ti.com (Vignesh R)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/5] spi: spi-ti-qspi: add mmap mode read support
Date: Thu, 5 Nov 2015 11:46:09 +0530 [thread overview]
Message-ID: <563AF429.1000406@ti.com> (raw)
In-Reply-To: <20151104144112.GJ1717@sirena.org.uk>
On 11/04/2015 08:11 PM, Mark Brown wrote:
> On Tue, Nov 03, 2015 at 03:36:11PM +0530, Vignesh R wrote:
>
>> + ti_qspi_enable_memory_map(spi);
>> + ti_qspi_setup_mmap_read(spi, read_opcode, addr_width,
>> + dummy_bytes);
>> + memcpy_fromio(buf, qspi->mmap_base + from, len);
>> + *retlen = len;
>> + ti_qspi_disable_memory_map(spi);
>
> We'll be constantly enabling and disabling memory mapping with this.
> I'm not sure that's a meaningful cost given that it doesn't actually
> remap anything but rather just switches hardware modes, we can always
> optimise it later if it is.
>
Hmm, I will move the ti_qspi_disable_memory_map() call to
ti_qspi_start_transfer_one(), so that mmap mode is disabled only when
normal SPI bus transfer is requested. Further, "mmap_enabled" status
flag can be used to determine whether mode switch is required or not.
This should help to overcome enabling and disabling memory mapping
between successive mmap read requests.
--
Regards
Vignesh
next prev parent reply other threads:[~2015-11-05 6:16 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-03 10:06 [PATCH v2 0/5] Add memory mapped read support for ti-qspi Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` [PATCH v2 1/5] spi: introduce mmap read support for spi flash devices Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 11:19 ` Michal Suchanek
2015-11-03 11:19 ` Michal Suchanek
2015-11-04 4:48 ` Vignesh R
2015-11-04 4:48 ` Vignesh R
2015-11-04 4:48 ` Vignesh R
2015-11-04 4:48 ` Vignesh R
2015-11-04 14:39 ` Mark Brown
2015-11-04 14:39 ` Mark Brown
2015-11-04 14:39 ` Mark Brown
2015-11-05 12:29 ` Vignesh R
2015-11-05 12:29 ` Vignesh R
2015-11-05 12:29 ` Vignesh R
2015-11-05 15:29 ` Mark Brown
2015-11-05 15:29 ` Mark Brown
2015-11-03 10:06 ` [PATCH v2 2/5] spi: spi-ti-qspi: add mmap mode read support Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-04 14:41 ` Mark Brown
2015-11-04 14:41 ` Mark Brown
2015-11-04 14:41 ` Mark Brown
2015-11-05 6:16 ` Vignesh R [this message]
2015-11-05 6:16 ` Vignesh R
2015-11-05 6:16 ` Vignesh R
2015-11-05 6:16 ` Vignesh R
2015-11-03 10:06 ` [PATCH v2 3/5] mtd: devices: m25p80: add support for mmap read request Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` [PATCH v2 4/5] ARM: dts: DRA7: add entry for qspi mmap region Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-05 16:36 ` Rob Herring
2015-11-05 16:36 ` Rob Herring
2015-11-05 16:36 ` Rob Herring
2015-11-03 10:06 ` [PATCH v2 5/5] ARM: dts: AM4372: " Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-03 10:06 ` Vignesh R
2015-11-05 23:51 ` Rob Herring
2015-11-05 23:51 ` Rob Herring
2015-11-05 23:51 ` Rob Herring
2015-11-06 5:14 ` Felipe Balbi
2015-11-06 5:14 ` Felipe Balbi
2015-11-06 5:14 ` Felipe Balbi
2015-11-06 12:21 ` Vignesh R
2015-11-06 12:21 ` Vignesh R
2015-11-06 12:21 ` Vignesh R
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