pcmcia: honor saved flags in yenta_socket's I365_CSCINT register

Instead of overwriting the I365_CSCINT register, save the old value and
merely change the bits we care about.

Part 1 of a series to allow the ISA irq to be used for Cardbus devices
if the socket's PCI irq is unusable.

[linux@dominikbrodowski.net: split up the original patch, commit message]

Signed-off-by: Jens Kuenzer <Jens.Kuenzer@fpga.homeip.net>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

2 files changed, 12 insertions, 4 deletions

diff --git a/drivers/pcmcia/i82365.h b/drivers/pcmcia/i82365.h
index 849ef1b5d687..3f84d7a2dc84 100644
--- a/drivers/pcmcia/i82365.h
+++ b/drivers/pcmcia/i82365.h
@@ -95,6 +95,7 @@
 #define I365_CSC_DETECT 0x08
 #define I365_CSC_ANY    0x0F
 #define I365_CSC_GPI    0x10
+#define I365_CSC_IRQ_MASK       0xF0
 
 /* Flags for I365_ADDRWIN */
 #define I365_ENA_IO(map)        (0x40 << (map))
diff --git a/drivers/pcmcia/yenta_socket.c b/drivers/pcmcia/yenta_socket.c
index 967c766f53ba..42f6763db400 100644
--- a/drivers/pcmcia/yenta_socket.c
+++ b/drivers/pcmcia/yenta_socket.c
@@ -356,7 +356,9 @@ static int yenta_set_socket(struct pcmcia_socket *sock, socket_state_t *state)
                         exca_writeb(socket, I365_POWER, reg);
 
                 /* CSC interrupt: no ISA irq for CSC */
-                reg = I365_CSC_DETECT;
+                reg = exca_readb(socket, I365_CSCINT);
+                reg &= I365_CSC_IRQ_MASK;
+                reg |= I365_CSC_DETECT;
                 if (state->flags & SS_IOCARD) {
                         if (state->csc_mask & SS_STSCHG)
                                 reg |= I365_CSC_STSCHG;
@@ -912,6 +914,7 @@ static unsigned int yenta_probe_irq(struct yenta_socket *socket, u32 isa_irq_mas
         int i;
         unsigned long val;
         u32 mask;
+        u8 reg;
 
         /*
          * Probe for usable interrupts using the force
@@ -919,6 +922,7 @@ static unsigned int yenta_probe_irq(struct yenta_socket *socket, u32 isa_irq_mas
          */
         cb_writel(socket, CB_SOCKET_EVENT, -1);
         cb_writel(socket, CB_SOCKET_MASK, CB_CSTSMASK);
+        reg = exca_readb(socket, I365_CSCINT);
         exca_writeb(socket, I365_CSCINT, 0);
         val = probe_irq_on() & isa_irq_mask;
         for (i = 1; i < 16; i++) {
@@ -930,7 +934,7 @@ static unsigned int yenta_probe_irq(struct yenta_socket *socket, u32 isa_irq_mas
                 cb_writel(socket, CB_SOCKET_EVENT, -1);
         }
         cb_writel(socket, CB_SOCKET_MASK, 0);
-        exca_writeb(socket, I365_CSCINT, 0);
+        exca_writeb(socket, I365_CSCINT, reg);
 
         mask = probe_irq_mask(val) & 0xffff;
 
@@ -967,6 +971,8 @@ static irqreturn_t yenta_probe_handler(int irq, void *dev_id)
 /* probes the PCI interrupt, use only on override functions */
 static int yenta_probe_cb_irq(struct yenta_socket *socket)
 {
+        u8 reg;
+
         if (!socket->cb_irq)
                 return -1;
 
@@ -979,7 +985,8 @@ static int yenta_probe_cb_irq(struct yenta_socket *socket)
         }
 
         /* generate interrupt, wait */
-        exca_writeb(socket, I365_CSCINT, I365_CSC_STSCHG);
+        reg = exca_readb(socket, I365_CSCINT);
+        exca_writeb(socket, I365_CSCINT, reg | I365_CSC_STSCHG);
         cb_writel(socket, CB_SOCKET_EVENT, -1);
         cb_writel(socket, CB_SOCKET_MASK, CB_CSTSMASK);
         cb_writel(socket, CB_SOCKET_FORCE, CB_FCARDSTS);
@@ -988,7 +995,7 @@ static int yenta_probe_cb_irq(struct yenta_socket *socket)
 
         /* disable interrupts */
         cb_writel(socket, CB_SOCKET_MASK, 0);
-        exca_writeb(socket, I365_CSCINT, 0);
+        exca_writeb(socket, I365_CSCINT, reg);
         cb_writel(socket, CB_SOCKET_EVENT, -1);
         exca_readb(socket, I365_CSC);