Re: [PATCH] Revert "reset: microchip-sparx5: allow building as a module"

From: Steen Hegelund <steen.hegelund@microchip.com>
To: Michael Walle <michael@walle.cc>, Philipp Zabel <p.zabel@pengutronix.de>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"Lars Povlsen" <lars.povlsen@microchip.com>,
	"Clément Léger" <clement.leger@bootlin.com>,
	"Claudiu Beznea" <claudiu.beznea@microchip.com>,
	"Kavyasree Kotagiri" <kavyasree.kotagiri@microchip.com>,
	"Horatiu Vultur" <horatiu.vultur@microchip.com>
Subject: Re: [PATCH] Revert "reset: microchip-sparx5: allow building as a module"
Date: Tue, 9 Aug 2022 12:19:57 +0200	[thread overview]
Message-ID: <ba44019b3c4ae9052ca6ddfa6673b7f1c71d8891.camel@microchip.com> (raw)
In-Reply-To: <38311987be9d29959bb303be9e3121ae@walle.cc>

Hi Michael,

Sorry, but most people have been OOO (including me), so this has delayed the response.

The protection bit protects the VCore Shared Bus (SBA) blocks shown on Figure 5-1. VCore System
Block Diagram in the Datasheet.  So in this case also the watchdog (which is the WDT block).

I hope this clarifies the usage.

Best Regards
Steen

On Thu, 2022-08-04 at 09:53 +0200, Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Am 2022-07-13 14:08, schrieb Philipp Zabel:
> > Hi,
> > 
> > On Mi, 2022-07-13 at 11:52 +0200, Michael Walle wrote:
> > > [+ Horatiu, I missed you earlier, sorry]
> > > 
> > > Hi Steen,
> > > 
> > > Am 2022-07-13 11:40, schrieb Steen Hegelund:
> > > > I am afraid that the exact list of affected modules is not available,
> > > > so using the
> > > > RESET_PROT_STAT.SYS_RST_PROT_VCORE bit is the best known way of
> > > > resetting as much as possible, and
> > > > still continue execution.
> > > 
> > > Mh, you are designing that chip (at least the LAN966x) no? Shouldn't
> > > that information be available anywhere at Microchip? ;)
> > > 
> > > Anyway, it looks like almost the whole chip is reset
> > > except some minor things. So the driver has actually a
> > > wrong name. Until recently only the switch driver was the
> > > sole user of it (at least on the lan966x). So, my question
> > > remains, is this correct? I mean the switch driver says,
> > > "reset the switch core", but what actually happens is that
> > > the the entire SoC except the CPU and maybe the io mux is reset.
> > > What about the watchdog for example? Will that be reset, too?
> > 
> > If [1-3] are to be trusted, RESET_PROT_STAT[VCORE_RST_PROT_WDT], which
> > protects the watchdog from soft reset, is not set by default. So yes?
> > 
> > There are also AMBA, PCIe, PDBG protection bits against Vcore soft
> > reset in this register, depending on the platform.
> > 
> > [1]
> > https://microchip-ung.github.io/sparx-5_reginfo/reginfo_sparx-5.html?select=cpu,cpu_regs,reset_prot_stat
> > [2]
> > https://microchip-ung.github.io/lan9662_reginfo/reginfo_LAN9662.html?select=cpu,cpu_regs,reset_prot_stat
> > [3]
> > https://microchip-ung.github.io/lan9668_reginfo/reginfo_LAN9668.html?select=cpu,cpu_regs,reset_prot_stat
> 
> Ping. any news here?
> 
> -michael

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