Messages in this thread | | | Subject | Re: [PATCH] spi: Updated PXA2xx SSP SPI Driver | From | Stephen Street <> | Date | Fri, 10 Feb 2006 14:19:41 -0800 |
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On Fri, 2006-02-10 at 12:40 -0500, Nicolas Pitre wrote: > [...] > > +#define SSP_REG(x) (*((volatile unsigned long *)x)) > > Don't do that. Instead, please use: > > #define DEFINE_SSP_REG(reg, off) \ > static inline u32 read_##reg(void *p) { return __raw_readl(p + (off)); \ > static inline void write_##reg(u32 v, void *p) { __raw_writel(v, p + (off)); } > > DEFINE_SSP_REG(SSCR0, 0x00) > DEFINE_SSP_REG(SSCR1, 0x04) > DEFINE_SSP_REG(SSSR, 0x08) > DEFINE_SSP_REG(SSITR, 0x0c) > DEFINE_SSP_REG(SSDR, 0x10) > DEFINE_SSP_REG(SSTO, 0x28) > DEFINE_SSP_REG(SSPSP, 0x2c) > Ok, I'll do this (Andrew made a similar comment). But...
I modeled my SSP_REG on the contents of include/asm- arm/arch_pxa/pxa_reg.h which makes extensive use of __REG defined in include/asm-arm/arch_pxa/hardware.h as
#define __REG(x) (*((volatile u32 *)io_p2v(x)))
which is effectively my SSP_REG without the io_p2v because I preloaded the virtual SSP register addresses in the pxa2xx_spi_probe function.
For my education:
Why are __raw_readl and friends better than exploiting the memory map I/O nature of the PXA2xx and other SOCs?
Especially since something like
SSP_REG(sscr1) &= ~SSCR1_TIE;
becomes
write_SSCR1(read_SSCR1(reg) & ~SSCR_TIE, reg);
Further what should I do with the DMA register accesses (i.e. DCSR, DCMD, etc)?
> +static void dma_handler(int channel, void *data, struct pt_regs *regs) > +{ > + struct driver_data *drv_data = (struct driver_data *)data; > + struct spi_message *msg = drv_data->cur_msg; > + u32 sssr = drv_data->sssr; > + u32 sscr1 = drv_data->sscr1; > + u32 ssto = drv_data->sscr1; > ^^^^^^^^^^^^^^^^^^^^^^^^^^ > Definitely wrong, harmless in this case but bad none the less. Thanks great eyes!
Stephen
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