[PATCH] smc91x: remove ARM hack for unaligned 16-bit writes
From: arnd@arndb.de (Arnd Bergmann)
Date: 2016-08-26 09:42:16
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Possibly related (same subject, not in this thread)
- 2016-08-25 · Re: [PATCH] smc91x: remove ARM hack for unaligned 16-bit writes · Arnd Bergmann <arnd@arndb.de>
- 2016-08-25 · [PATCH] smc91x: remove ARM hack for unaligned 16-bit writes · Arnd Bergmann <arnd@arndb.de>
On Thursday, August 25, 2016 11:37:43 PM CEST Russell King - ARM Linux wrote:
quoted hunk ↗ jump to hunk
On Thu, Aug 25, 2016 at 08:02:35PM +0200, Robert Jarzmik wrote:quoted
Arnd Bergmann [off-list ref] writes:/* + * Any 16-bit access is performed with two 8-bit accesses if the hardware + * can't do it directly. Most registers are 16-bit so those are mandatory. + */ +#define SMC_outw_b(x, a, r) \ + do { \ + unsigned int __val16 = (x); \ + unsigned int __reg = (r); \ + SMC_outb(__val16, a, __reg); \ + SMC_outb(__val16 >> 8, a, __reg + (1 << SMC_IO_SHIFT)); \ + } while (0) + +#define SMC_inw_b(a, r) \ + ({ \ + unsigned int __val16; \ + unsigned int __reg = r; \ + __val16 = SMC_inb(a, __reg); \ + __val16 |= SMC_inb(a, __reg + (1 << SMC_IO_SHIFT)) << 8; \ + __val16; \ + }) + +/* * Define your architecture specific bus configuration parameters here. */@@ -55,10 +76,30 @@ #define SMC_IO_SHIFT (lp->io_shift) #define SMC_inb(a, r) readb((a) + (r)) -#define SMC_inw(a, r) readw((a) + (r)) +#define SMC_inw(a, r) \ + ({ \ + unsigned int __smc_r = r; \ + SMC_16BIT(lp) ? readw((a) + __smc_r) : \ + SMC_8BIT(lp) ? SMC_inw_b(a, __smc_r) : \ + ({ BUG(); 0; }); \ + }) +
I think this breaks machines that declare a device that just lists SMC91X_USE_32BIT but not SMC91X_USE_16BIT. Right now, the way this is interpreted is to use 32-bit accessors for most things, but not avoiding 16-bit reads. That is a bit fishy though, and we could instead change the platform data to always set both SMC91X_USE_32BIT and SMC91X_USE_16BIT. The affected platforms are DT based machines with 32-bit I/O and these board files: arch/arm/mach-pxa/idp.c: .flags = SMC91X_USE_32BIT | SMC91X_USE_DMA | SMC91X_NOWAIT, arch/arm/mach-pxa/xcep.c: .flags = SMC91X_USE_32BIT | SMC91X_NOWAIT | SMC91X_USE_DMA, arch/arm/mach-realview/core.c: .flags = SMC91X_USE_32BIT | SMC91X_NOWAIT, arch/blackfin/mach-bf561/boards/cm_bf561.c: .flags = SMC91X_USE_32BIT | SMC91X_NOWAIT, arch/blackfin/mach-bf561/boards/ezkit.c: .flags = SMC91X_USE_32BIT | SMC91X_NOWAIT, Arnd