FDDI: defxx: Implement dynamic CSR I/O address space selection

Recent versions of the PCI Express specification have deprecated support
for I/O transactions and actually some PCIe host bridges, such as Power
Systems Host Bridge 4 (PHB4), do not implement them.  Conversely a DEFEA
adapter can have its MMIO decoding disabled with ECU (EISA Configuration
Utility) and therefore not available for us with the resource allocation
infrastructure we implement.

However either I/O address space will always be available for use with
the DEFEA (EISA) and DEFPA (PCI) adapters and both have double address
decoding implemented in hardware for Control and Status Register access.
The two kinds of adapters can be present both at once in a single mixed
PCI/EISA system.  For the DEFTA (TURBOchannel) variant there is no issue
as there has been no port I/O address space defined for that bus.

To make people's life easier and the driver more robust remove the
DEFXX_MMIO configuration option so as to rather than making the choice
for the I/O address space to use at build time for all the adapters
installed in the system let the driver choose the most suitable address
space dynamically on a case-by-case basis at run time.  Make MMIO the
default and resort to port I/O should the default fail for some reason.

This way multiple adapters installed in one system can use different I/O
address spaces each, in particular in the presence of DEFEA adapters in
a pure-EISA or a mixed EISA/PCI system (it is expected that DEFPA boards
will use MMIO in normal circumstances).

The choice of the I/O address space to use continues being reported by
the driver on startup, e.g.:

eisa 00:05: EISA: slot 5: DEC3002 detected
defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
00:05: DEFEA at I/O addr = 0x5000, IRQ = 10, Hardware addr = 00-00-f8-c8-b3-b6
00:05: registered as fddi0

and:

defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
0031:02:04.0: DEFPA at MMIO addr = 0x620c080020000, IRQ = 57, Hardware addr = 00-60-6d-93-91-98
0031:02:04.0: registered as fddi0

and:

defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
tc2: DEFTA at MMIO addr = 0x1f100000, IRQ = 21, Hardware addr = 08-00-2b-b0-8b-1e
tc2: registered as fddi0

so there is no need to add further information.

The change is supposed to cause a negligible performance hit as I/O
accessors will now have code executed conditionally at run time.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/fddi/Kconfig b/drivers/net/fddi/Kconfig
index f99c104..846bf41 100644 (file)
--- a/drivers/net/fddi/Kconfig
+++ b/drivers/net/fddi/Kconfig
@@ -38,25 +38,6 @@ config DEFXX
          To compile this driver as a module, choose M here: the module
          will be called defxx.  If unsure, say N.
 
-config DEFXX_MMIO
-       bool
-       prompt "Use MMIO instead of IOP" if PCI || EISA
-       depends on DEFXX
-       default n if EISA
-       default y
-       help
-         This instructs the driver to use EISA or PCI memory-mapped I/O
-         (MMIO) as appropriate instead of programmed I/O ports (IOP).
-         Enabling this gives an improvement in processing time in parts
-         of the driver, but it requires a memory window to be configured
-         for EISA (DEFEA) adapters that may not always be available.
-         Conversely some PCIe host bridges do not support IOP, so MMIO
-         may be required to access PCI (DEFPA) adapters on downstream PCI
-         buses with some systems.  TURBOchannel does not have the concept
-         of I/O ports, so MMIO is always used for these (DEFTA) adapters.
-
-         If unsure, say N.
-
 config SKFP
        tristate "SysKonnect FDDI PCI support"
        depends on FDDI && PCI

diff --git a/drivers/net/fddi/defxx.c b/drivers/net/fddi/defxx.c
index c62d4b5..7d733a6 100644 (file)
--- a/drivers/net/fddi/defxx.c
+++ b/drivers/net/fddi/defxx.c
@@ -197,6 +197,7 @@
  *             23 Oct 2006     macro           Big-endian host support.
  *             14 Dec 2006     macro           TURBOchannel support.
  *             01 Jul 2014     macro           Fixes for DMA on 64-bit hosts.
+ *             10 Mar 2021     macro           Dynamic MMIO vs port I/O.
  */
 
 /* Include files */
@@ -225,8 +226,8 @@
 
 /* Version information string should be updated prior to each new release!  */
 #define DRV_NAME "defxx"
-#define DRV_VERSION "v1.11"
-#define DRV_RELDATE "2014/07/01"
+#define DRV_VERSION "v1.12"
+#define DRV_RELDATE "2021/03/10"
 
 static const char version[] =
        DRV_NAME ": " DRV_VERSION " " DRV_RELDATE
@@ -253,10 +254,10 @@ static const char version[] =
 #define DFX_BUS_TC(dev) 0
 #endif
 
-#ifdef CONFIG_DEFXX_MMIO
-#define DFX_MMIO 1
+#if defined(CONFIG_EISA) || defined(CONFIG_PCI)
+#define dfx_use_mmio bp->mmio
 #else
-#define DFX_MMIO 0
+#define dfx_use_mmio true
 #endif
 
 /* Define module-wide (static) routines */
@@ -374,8 +375,6 @@ static inline void dfx_outl(DFX_board_t *bp, int offset, u32 data)
 static void dfx_port_write_long(DFX_board_t *bp, int offset, u32 data)
 {
        struct device __maybe_unused *bdev = bp->bus_dev;
-       int dfx_bus_tc = DFX_BUS_TC(bdev);
-       int dfx_use_mmio = DFX_MMIO || dfx_bus_tc;
 
        if (dfx_use_mmio)
                dfx_writel(bp, offset, data);
@@ -398,8 +397,6 @@ static inline void dfx_inl(DFX_board_t *bp, int offset, u32 *data)
 static void dfx_port_read_long(DFX_board_t *bp, int offset, u32 *data)
 {
        struct device __maybe_unused *bdev = bp->bus_dev;
-       int dfx_bus_tc = DFX_BUS_TC(bdev);
-       int dfx_use_mmio = DFX_MMIO || dfx_bus_tc;
 
        if (dfx_use_mmio)
                dfx_readl(bp, offset, data);
@@ -421,7 +418,7 @@ static void dfx_port_read_long(DFX_board_t *bp, int offset, u32 *data)
  *   None
  *
  * Arguments:
- *   bdev      - pointer to device information
+ *   bp                - pointer to board information
  *   bar_start - pointer to store the start addresses
  *   bar_len   - pointer to store the lengths of the areas
  *
@@ -431,13 +428,13 @@ static void dfx_port_read_long(DFX_board_t *bp, int offset, u32 *data)
  * Side Effects:
  *   None
  */
-static void dfx_get_bars(struct device *bdev,
+static void dfx_get_bars(DFX_board_t *bp,
                         resource_size_t *bar_start, resource_size_t *bar_len)
 {
+       struct device *bdev = bp->bus_dev;
        int dfx_bus_pci = dev_is_pci(bdev);
        int dfx_bus_eisa = DFX_BUS_EISA(bdev);
        int dfx_bus_tc = DFX_BUS_TC(bdev);
-       int dfx_use_mmio = DFX_MMIO || dfx_bus_tc;
 
        if (dfx_bus_pci) {
                int num = dfx_use_mmio ? 0 : 1;
@@ -495,18 +492,6 @@ static const struct net_device_ops dfx_netdev_ops = {
        .ndo_set_mac_address    = dfx_ctl_set_mac_address,
 };
 
-static void dfx_register_res_alloc_err(const char *print_name, bool mmio,
-                                      bool eisa)
-{
-       pr_err("%s: Cannot use %s, no address set, aborting\n",
-              print_name, mmio ? "MMIO" : "I/O");
-       pr_err("%s: Recompile driver with \"CONFIG_DEFXX_MMIO=%c\"\n",
-              print_name, mmio ? 'n' : 'y');
-       if (eisa && mmio)
-               pr_err("%s: Or run ECU and set adapter's MMIO location\n",
-                      print_name);
-}
-
 static void dfx_register_res_err(const char *print_name, bool mmio,
                                 unsigned long start, unsigned long len)
 {
@@ -547,8 +532,6 @@ static int dfx_register(struct device *bdev)
        static int version_disp;
        int dfx_bus_pci = dev_is_pci(bdev);
        int dfx_bus_eisa = DFX_BUS_EISA(bdev);
-       int dfx_bus_tc = DFX_BUS_TC(bdev);
-       int dfx_use_mmio = DFX_MMIO || dfx_bus_tc;
        const char *print_name = dev_name(bdev);
        struct net_device *dev;
        DFX_board_t       *bp;                  /* board pointer */
@@ -586,19 +569,24 @@ static int dfx_register(struct device *bdev)
        bp->bus_dev = bdev;
        dev_set_drvdata(bdev, dev);
 
-       dfx_get_bars(bdev, bar_start, bar_len);
+       bp->mmio = true;
+
+       dfx_get_bars(bp, bar_start, bar_len);
        if (bar_len[0] == 0 ||
            (dfx_bus_eisa && dfx_use_mmio && bar_start[0] == 0)) {
-               dfx_register_res_alloc_err(print_name, dfx_use_mmio,
-                                          dfx_bus_eisa);
-               err = -ENXIO;
-               goto err_out_disable;
+               bp->mmio = false;
+               dfx_get_bars(bp, bar_start, bar_len);
        }
 
-       if (dfx_use_mmio)
+       if (dfx_use_mmio) {
                region = request_mem_region(bar_start[0], bar_len[0],
                                            print_name);
-       else
+               if (!region && (dfx_bus_eisa || dfx_bus_pci)) {
+                       bp->mmio = false;
+                       dfx_get_bars(bp, bar_start, bar_len);
+               }
+       }
+       if (!dfx_use_mmio)
                region = request_region(bar_start[0], bar_len[0], print_name);
        if (!region) {
                dfx_register_res_err(print_name, dfx_use_mmio,
@@ -734,7 +722,6 @@ static void dfx_bus_init(struct net_device *dev)
        int dfx_bus_pci = dev_is_pci(bdev);
        int dfx_bus_eisa = DFX_BUS_EISA(bdev);
        int dfx_bus_tc = DFX_BUS_TC(bdev);
-       int dfx_use_mmio = DFX_MMIO || dfx_bus_tc;
        u8 val;
 
        DBG_printk("In dfx_bus_init...\n");
@@ -1054,7 +1041,6 @@ static int dfx_driver_init(struct net_device *dev, const char *print_name,
        int dfx_bus_pci = dev_is_pci(bdev);
        int dfx_bus_eisa = DFX_BUS_EISA(bdev);
        int dfx_bus_tc = DFX_BUS_TC(bdev);
-       int dfx_use_mmio = DFX_MMIO || dfx_bus_tc;
        int alloc_size;                 /* total buffer size needed */
        char *top_v, *curr_v;           /* virtual addrs into memory block */
        dma_addr_t top_p, curr_p;       /* physical addrs into memory block */
@@ -3708,8 +3694,6 @@ static void dfx_unregister(struct device *bdev)
        struct net_device *dev = dev_get_drvdata(bdev);
        DFX_board_t *bp = netdev_priv(dev);
        int dfx_bus_pci = dev_is_pci(bdev);
-       int dfx_bus_tc = DFX_BUS_TC(bdev);
-       int dfx_use_mmio = DFX_MMIO || dfx_bus_tc;
        resource_size_t bar_start[3] = {0};     /* pointers to ports */
        resource_size_t bar_len[3] = {0};       /* resource lengths */
        int             alloc_size;             /* total buffer size used */
@@ -3729,7 +3713,7 @@ static void dfx_unregister(struct device *bdev)
 
        dfx_bus_uninit(dev);
 
-       dfx_get_bars(bdev, bar_start, bar_len);
+       dfx_get_bars(bp, bar_start, bar_len);
        if (bar_start[2] != 0)
                release_region(bar_start[2], bar_len[2]);
        if (bar_start[1] != 0)

diff --git a/drivers/net/fddi/defxx.h b/drivers/net/fddi/defxx.h
index 4c31d31..8193713 100644 (file)
--- a/drivers/net/fddi/defxx.h
+++ b/drivers/net/fddi/defxx.h
@@ -27,6 +27,7 @@
  *             04 Aug 2003     macro           Converted to the DMA API.
  *             23 Oct 2006     macro           Big-endian host support.
  *             14 Dec 2006     macro           TURBOchannel support.
+ *             10 Mar 2021     macro           Dynamic MMIO vs port I/O.
  */
 
 #ifndef _DEFXX_H_
@@ -1776,6 +1777,8 @@ typedef struct DFX_board_tag
                int port;
        } base;                                                                         /* base address */
        struct device                   *bus_dev;
+       /* Whether to use MMIO or port I/O.  */
+       bool                            mmio;
        u32                             full_duplex_enb;                                /* FDDI Full Duplex enable (1 == on, 2 == off) */
        u32                             req_ttrt;                                       /* requested TTRT value (in 80ns units) */
        u32                             burst_size;                                     /* adapter burst size (enumerated) */