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Disable write buffering on Toshiba ToPIC95 

Disable write buffering on the Toshiba ToPIC95 if it is enabled by
somebody (it is not supposed to be a power-on default according to
the datasheet). On the ToPIC95, practically no 32-bit Cardbus card
will work under heavy load without locking up the whole system if
this is left enabled. I tried about a dozen. It does not affect
16-bit cards. This is similar to the O2 bugs in early controller
revisions it seems.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55961
Cc: <stable@vger.kernel.org>
Signed-off-by: Ryan C. Underwood <nemesis@icequake.net>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
hifive-unleashed-5.1
Ryan Underwood 2015-01-25 16:07:09 -08:00 committed by Dominik Brodowski
parent f2e6cf7675
commit 2fb22a8042
1 changed files with 16 additions and 0 deletions
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16
drivers/pcmcia/topic.h
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@ -104,6 +104,9 @@
#define TOPIC_EXCA_IF_CONTROL 0x3e /* 8 bit */
#define TOPIC_EXCA_IFC_33V_ENA 0x01
#define TOPIC_PCI_CFG_PPBCN 0x3e /* 16-bit */
#define TOPIC_PCI_CFG_PPBCN_WBEN 0x0400
static void topic97_zoom_video(struct pcmcia_socket *sock, int onoff)
{
struct yenta_socket *socket = container_of(sock, struct yenta_socket, socket);
@ -138,6 +141,7 @@ static int topic97_override(struct yenta_socket *socket)
static int topic95_override(struct yenta_socket *socket)
{
u8 fctrl;
u16 ppbcn;
/* enable 3.3V support for 16bit cards */
fctrl = exca_readb(socket, TOPIC_EXCA_IF_CONTROL);
@ -146,6 +150,18 @@ static int topic95_override(struct yenta_socket *socket)
/* tell yenta to use exca registers to power 16bit cards */
socket->flags |= YENTA_16BIT_POWER_EXCA | YENTA_16BIT_POWER_DF;
/* Disable write buffers to prevent lockups under load with numerous
Cardbus cards, observed on Tecra 500CDT and reported elsewhere on the
net. This is not a power-on default according to the datasheet
but some BIOSes seem to set it. */
if (pci_read_config_word(socket->dev, TOPIC_PCI_CFG_PPBCN, &ppbcn) == 0
&& socket->dev->revision <= 7
&& (ppbcn & TOPIC_PCI_CFG_PPBCN_WBEN)) {
ppbcn &= ~TOPIC_PCI_CFG_PPBCN_WBEN;
pci_write_config_word(socket->dev, TOPIC_PCI_CFG_PPBCN, ppbcn);
dev_info(&socket->dev->dev, "Disabled ToPIC95 Cardbus write buffers.\n");
}
return 0;
}