|
From: | Hao Wu |
Subject: | Re: [PATCH v2 5/7] hw/nvram: Update at24c EEPROM init function in NPCM7xx boards |
Date: | Wed, 3 Nov 2021 14:52:20 -0700 |
On 01/11/2021 18.47, Hao Wu wrote:
>
>
> On Mon, Nov 1, 2021 at 10:41 AM Peter Maydell <peter.maydell@linaro.org
> <mailto:peter.maydell@linaro.org>> wrote:
>
> On Thu, 21 Oct 2021 at 19:40, Hao Wu <wuhaotsh@google.com
> <mailto:wuhaotsh@google.com>> wrote:
> >
> > We made 3 changes to the at24c_eeprom_init function in
> > npcm7xx_boards.c:
> >
> > 1. We allow the function to take a I2CBus* as parameter. This allows
> > us to attach an EEPROM device behind an I2C mux which is not
> > possible with the old method.
> >
> > 2. We make at24c EEPROMs are backed by drives so that we can
> > specify the content of the EEPROMs.
> >
> > 3. Instead of using i2c address as unit number, This patch assigns
> > unique unit numbers for each eeproms in each board. This avoids
> > conflict in providing multiple eeprom contents with the same address.
> > In the old method if we specify two drives with the same unit number,
> > the following error will occur: `Device with id 'none85' exists`.
> >
> > Signed-off-by: Hao Wu <wuhaotsh@google.com <mailto:wuhaotsh@google.com>>
> > ---
> > hw/arm/npcm7xx_boards.c | 15 ++++++++++-----
> > 1 file changed, 10 insertions(+), 5 deletions(-)
> >
> > diff --git a/hw/arm/npcm7xx_boards.c b/hw/arm/npcm7xx_boards.c
> > index a656169f61..cdb52b9922 100644
> > --- a/hw/arm/npcm7xx_boards.c
> > +++ b/hw/arm/npcm7xx_boards.c
> > @@ -107,13 +107,18 @@ static I2CBus *npcm7xx_i2c_get_bus(NPCM7xxState
> *soc, uint32_t num)
> > return I2C_BUS(qdev_get_child_bus(DEVICE(&soc->smbus[num]),
> "i2c-bus"));
> > }
> >
> > -static void at24c_eeprom_init(NPCM7xxState *soc, int bus, uint8_t addr,
> > - uint32_t rsize)
> > +static void at24c_eeprom_init(I2CBus *i2c_bus, int bus, uint8_t addr,
> > + uint32_t rsize, int unit_number)
> > {
> > - I2CBus *i2c_bus = npcm7xx_i2c_get_bus(soc, bus);
> > I2CSlave *i2c_dev = i2c_slave_new("at24c-eeprom", addr);
> > DeviceState *dev = DEVICE(i2c_dev);
> > + BlockInterfaceType type = IF_NONE;
>
> Why make this a variable? We only use it in one place...
>
> You're right, we can actually inline it.
Actually, please do *not* use IF_NONE for such stuff. See the discussion
here for details:
https://lists.gnu.org/archive/html/qemu-devel/2021-11/msg00970.html
Thomas
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