Hi List,
On Fri, May 24, 2019 at 01:32:41PM +0200, Sven Schnelle wrote:
> > Did a quick test, removing ALT_COND_N_IOC_FDC from asm_io_fdc() seems to fix this
> > issue. Haven't looked in more detail into this though.
>
> Added some debugging:
>
> [ 25.405365] boot_cpu_data.pdc_capabilities: 2
>
> So PDC says IO-PDIR fetches are not performed coherently, *BUT*:
>
> When this bit is clear, flushes and syncs are not required. This
> bit is only applicable to SBAs, and does not apply to Legacy IOAs.
>
> With my limited understand i would think that C240 has a 'Legacy IOA' while
> C3xxx has SBA? So i think we would need to add some check whether we have
> an IOA or SBA in the alternatives code?
I did the patch below to check for legacy IO Adapters. Is HW_BCPORT the right
type? On my C240 both GSC Adapters are HW_BCPORT.
>From a5a444d0eb4960d7a1c7c4acf5eeb86b4e11e358 Mon Sep 17 00:00:00 2001
From: Sven Schnelle <svens@xxxxxxxxxxxxxx>
Date: Fri, 24 May 2019 17:33:28 +0200
Subject: [PATCH] parisc: fix alternative patching for Legacy IO systems
On systems with legacy IO Adapters we must ignore the IO-PDIR
bit we get in the PDC_MODEL response. This fixes booting on
HP9000/C240.
Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxxx>
---
arch/parisc/include/asm/hardware.h | 1 +
arch/parisc/kernel/alternative.c | 8 +++++---
arch/parisc/kernel/drivers.c | 14 ++++++++++++++
3 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/arch/parisc/include/asm/hardware.h b/arch/parisc/include/asm/hardware.h
index 9d3d7737c58b..5fb7a3c3eb46 100644
--- a/arch/parisc/include/asm/hardware.h
+++ b/arch/parisc/include/asm/hardware.h
@@ -121,6 +121,7 @@ extern void init_parisc_bus(void);
extern struct device *hwpath_to_device(struct hardware_path *modpath);
extern void device_to_hwpath(struct device *dev, struct hardware_path *path);
extern int machine_has_merced_bus(void);
+extern int machine_has_ioa(void);
/* inventory.c: */
extern void do_memory_inventory(void);
diff --git a/arch/parisc/kernel/alternative.c b/arch/parisc/kernel/alternative.c
index bf2274e01a96..ca6368e6e96a 100644
--- a/arch/parisc/kernel/alternative.c
+++ b/arch/parisc/kernel/alternative.c
@@ -25,6 +25,7 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
struct alt_instr *entry;
int index = 0, applied = 0;
int num_cpus = num_online_cpus();
+ int has_ioa = machine_has_ioa();
for (entry = start; entry < end; entry++, index++) {
@@ -53,10 +54,11 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
/*
* If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
* set (bit #61, big endian), we have to flush and sync every
- * time IO-PDIR is changed in Ike/Astro.
+ * time IO-PDIR is changed in Ike/Astro. If legacy IOAs are
+ * present we're not allowed to skip these flushes/syncs.
*/
- if ((cond & ALT_COND_NO_IOC_FDC) &&
- (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC))
+ if (((cond & ALT_COND_NO_IOC_FDC) && (has_ioa ||
+ (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC))))
continue;
/* Want to replace pdtlb by a pdtlb,l instruction? */
diff --git a/arch/parisc/kernel/drivers.c b/arch/parisc/kernel/drivers.c
index 00a181f1ecc6..4c93b416df99 100644
--- a/arch/parisc/kernel/drivers.c
+++ b/arch/parisc/kernel/drivers.c
@@ -282,6 +282,20 @@ int __init machine_has_merced_bus(void)
return ret ? 1 : 0;
}
+static int __init is_IOA_device(struct device *dev, void *data)
+{
+ struct parisc_device *pdev = to_parisc_device(dev);
+
+ if (!check_dev(dev))
+ return 0;
+ return pdev->id.hw_type == HPHW_BCPORT;
+}
+
+int __init machine_has_ioa(void)
+{
+ return !!for_each_padev(is_IOA_device, NULL);
+}
+
/**
* find_pa_parent_type - Find a parent of a specific type
* @dev: The device to start searching from
--
2.20.1
