From: sameo@linux.intel.com (Samuel Ortiz)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 01/13] mfd: pruss mfd driver.
Date: Tue, 22 Feb 2011 11:31:27 +0100 [thread overview]
Message-ID: <20110222103127.GC30279@sortiz-mobl> (raw)
In-Reply-To: <37B3755C4AE64BAA805DFBAEBDC3D9E4@subhasishg>
Hi Subhasish,
On Tue, Feb 22, 2011 at 11:13:38AM +0530, Subhasish Ghosh wrote:
> Thank you for your comments.
No problem.
> >>diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> >>index fd01836..6c437df 100644
> >>--- a/drivers/mfd/Kconfig
> >>+++ b/drivers/mfd/Kconfig
> >>@@ -81,6 +81,16 @@ config MFD_DM355EVM_MSP
> >> boards. MSP430 firmware manages resets and power sequencing,
> >> inputs from buttons and the IR remote, LEDs, an RTC, and more.
> >>
> >>+config MFD_DA8XX_PRUSS
> >>+ tristate "Texas Instruments DA8XX PRUSS support"
> >>+ depends on ARCH_DAVINCI && ARCH_DAVINCI_DA850
> >Why are we depending on those ?
>
> SG -- The PRUSS core in only available within DA850 and DA830,
> DA830 support is not yet implemented.
Sure, but if there are no actual code dependencies, I'd like to get rid of
those depends.
> >>+u32 pruss_disable(struct device *dev, u8 pruss_num)
> >>+{
> >>+ struct da8xx_pruss *pruss = dev_get_drvdata(dev->parent);
> >>+ da8xx_prusscore_regs h_pruss;
> >>+ u32 temp_reg;
> >>+
> >>+ if (pruss_num == DA8XX_PRUCORE_0) {
> >>+ /* Disable PRU0 */
> >>+ h_pruss = (da8xx_prusscore_regs)
> >>+ ((u32) pruss->ioaddr + 0x7000);
> >So it seems you're doing this in several places, and I have a few
> >comments:
> >
> >- You don't need the da8xx_prusscore_regs at all.
> >- Define the register map through a set of #define in your header file.
> >- Use a static routine that takes the core number and returns the
> >register map
> >offset.
> >
> >Then routines like this one will look a lot more readable.
>
> SG -- There are a huge number of PRUSS registers. A lot of them are
> reserved and are expected to change as development on the
> controller is still ongoing.
First of all, from what I read in your patch you're only using the CONTROL
offset.
> If we use #defines to plot
> all the registers, then first, there are too many array type
> registers which will need to be duplicated.
What I'm expecting is a small set of defines for the register offsets. You
have 13 fields in your da8xx_prusscore_regs, you only need to define 13
register offsets.
So, if you have a:
static u32 reg_offset(struct device *dev, u8 pru_num)
{
struct da8xx_pruss *pru = dev_get_drvdata(dev->parent);
switch (pru_num) {
case DA8XX_PRUCORE_0:
return (u32) pru->ioaddr + 0x7000;
case DA8XX_PRUCORE_1:
return (u32) pru->ioaddr + 0x7800;
default:
return 0;
}
then routines like pruss_enable (which should return an int, btw) would look
like:
int pruss_enable(struct device *dev, u8 pruss_num)
{
u32 offset = reg_offset(dev, pruss_num);
if (offset == 0)
return -EINVAL;
__raw_writel(DA8XX_PRUCORE_CONTROL_RESETVAL,
offset + PRU_CORE_CONTROL);
return 0;
}
> >Also, all your exported routines severely lack any sort of locking. An IO
> >mutex or spinlock is mandatory here.
>
> SG - As per our current implementation, we do not have two devices
> running simultaneously on the PRU,
> so we do not have any way to test it. We have kept this as an
> enhancement if request comes in for
> multiple devices.
It's not about having multiple devices at the same time, it's about having
multiple callers writing and reading to the same registers. Since you're
exporting all your I/O routines you have no way to prevent 2 drivers from
writing to the same register at the "same" time. You need locking here,
regardless of the number of devices that you can have on a system.
> >>+static int pruss_mfd_add_devices(struct platform_device *pdev)
> >>+{
> >>+ struct da8xx_pruss_devices *dev_data = pdev->dev.platform_data;
> >>+ struct device *dev = &pdev->dev;
> >>+ struct mfd_cell cell;
> >>+ u32 err, count;
> >>+
> >>+ for (count = 0; (dev_data + count)->dev_name != NULL; count++) {
> >>+ memset(&cell, 0, sizeof(struct mfd_cell));
> >>+ cell.id = count;
> >>+ cell.name = (dev_data + count)->dev_name;
> >>+ cell.platform_data = (dev_data + count)->pdata;
> >>+ cell.data_size = (dev_data + count)->pdata_size;
> >>+
> >>+ err = mfd_add_devices(dev, 0, &cell, 1, NULL, 0);
> >>+ if (err) {
> >>+ dev_err(dev, "cannot add mfd cells\n");
> >>+ return err;
> >>+ }
> >>+ }
> >>+ return err;
> >>+}
> >So, what are the potential subdevices for this driver ? If it's a really
> >dynamic setup, I'm fine with passing those as platform data but
> >then do it so
> >that you pass a NULL terminated da8xx_pruss_devices array. That will avoid
> >most of the ugly casts you're doing here.
>
> SG -- I did not follow your recommendations here, could you please
> elaborate.
> I am already checking the dev_name for a NULL.
> This device is basically a microcontroller within DA850,
> so basically any device or protocol can be
> emulated on it. Currently, we have emulated 8 UARTS using
> the two PRUs and also a CAN device.
Ok, I wasnt sure you can emulate anything on that thing. So I'm fine with you
passing all your devices through platform_data. But I'd prefer this routine to
look like:
[...]
for (count = 0; dev_data[count] != NULL; count++) {
memset(&cell, 0, sizeof(struct mfd_cell));
cell.id = count;
cell.name = dev_data[count]->dev_name;
cell.platform_data = dev_data[count]->pdata;
cell.data_size = dev_data[count]->pdata_size;
Looks nicer to me.
Cheers,
Samuel.
--
Intel Open Source Technology Centre
http://oss.intel.com/
next prev parent reply other threads:[~2011-02-22 10:31 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-11 14:51 [PATCH v2 00/13] pruss mfd drivers Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 01/13] mfd: pruss mfd driver Subhasish Ghosh
2011-02-21 16:30 ` Samuel Ortiz
2011-02-22 5:43 ` Subhasish Ghosh
2011-02-22 10:31 ` Samuel Ortiz [this message]
2011-02-22 10:48 ` Wolfgang Grandegger
2011-02-22 11:33 ` Samuel Ortiz
2011-02-22 12:49 ` Subhasish Ghosh
2011-02-22 16:27 ` Wolfgang Grandegger
2011-02-23 12:25 ` Subhasish Ghosh
2011-02-23 13:09 ` Russell King - ARM Linux
2011-02-11 14:51 ` [PATCH v2 02/13] da850: pruss platform specific additions Subhasish Ghosh
2011-02-11 18:41 ` Sergei Shtylyov
2011-02-18 7:18 ` Subhasish Ghosh
2011-02-28 13:04 ` TK, Pratheesh Gangadhar
2011-03-01 6:59 ` Subhasish Ghosh
2011-03-03 11:12 ` TK, Pratheesh Gangadhar
2011-02-11 14:51 ` [PATCH v2 03/13] da850: pruss board " Subhasish Ghosh
2011-02-11 18:43 ` Sergei Shtylyov
2011-02-18 7:18 ` Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 04/13] mfd: pruss CAN private data Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 05/13] da850: pruss CAN platform specific additions Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 06/13] da850: pruss CAN board " Subhasish Ghosh
2011-02-11 18:45 ` Sergei Shtylyov
2011-02-18 7:19 ` Subhasish Ghosh
2011-02-18 7:19 ` Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 07/13] da850: pruss CAN platform specific changes for gpios Subhasish Ghosh
2011-02-11 18:47 ` Sergei Shtylyov
2011-02-18 7:20 ` Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 08/13] da850: pruss CAN board " Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 09/13] can: pruss CAN driver Subhasish Ghosh
2011-02-11 15:06 ` Kurt Van Dijck
2011-02-14 4:54 ` Subhasish Ghosh
[not found] ` <4D58D854.5090503@grandegger.com>
2011-02-14 7:42 ` Kurt Van Dijck
2011-02-14 8:45 ` Subhasish Ghosh
[not found] ` <4D58F77B.9080005@pengutronix.de>
2011-02-14 13:15 ` Subhasish Ghosh
2011-02-11 15:20 ` Kurt Van Dijck
2011-02-18 7:07 ` Subhasish Ghosh
[not found] ` <4D5E2570.10108@grandegger.com>
2011-02-18 8:15 ` Subhasish Ghosh
2011-02-18 8:36 ` Marc Kleine-Budde
2011-02-18 9:09 ` Subhasish Ghosh
2011-02-18 15:07 ` Arnd Bergmann
2011-03-22 7:30 ` Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 10/13] mfd: pruss SUART private data Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 11/13] da850: pruss SUART board specific additions Subhasish Ghosh
2011-02-11 15:26 ` Michael Williamson
2011-02-18 7:13 ` Subhasish Ghosh
2011-02-11 18:50 ` Sergei Shtylyov
2011-02-22 6:22 ` Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 12/13] da850: pruss SUART platform " Subhasish Ghosh
2011-02-11 18:55 ` Sergei Shtylyov
2011-02-22 9:18 ` Subhasish Ghosh
2011-02-22 11:20 ` Sergei Shtylyov
2011-02-22 13:24 ` Subhasish Ghosh
2011-02-11 14:51 ` [PATCH v2 13/13] tty: pruss SUART driver Subhasish Ghosh
2011-02-11 16:28 ` Alan Cox
2011-02-18 13:47 ` Subhasish Ghosh
2011-02-18 14:35 ` Alan Cox
2011-02-18 18:23 ` Thomas Gleixner
2011-02-18 18:51 ` Arnd Bergmann
2011-02-22 8:42 ` Subhasish Ghosh
2011-02-22 14:37 ` Greg KH
2011-02-23 5:30 ` Subhasish Ghosh
2011-02-23 18:20 ` Greg KH
2011-02-22 8:43 ` Subhasish Ghosh
2011-02-22 16:34 ` Arnd Bergmann
2011-02-24 10:31 ` Subhasish Ghosh
2011-02-22 10:26 ` Subhasish
2011-02-22 11:11 ` Alan Cox
2011-03-01 13:37 ` Subhasish Ghosh
2011-03-01 14:07 ` Alan Cox
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