linux-kernel - Re: [PATCH 19/41] ARM: omap: dma: make usb support optional

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Message-ID: <a9e1b5ce-861f-021b-b41f-62e5298c11e5@gmail.com>
Date:   Fri, 29 Apr 2022 22:24:19 +0300
From:   Péter Ujfalusi <peter.ujfalusi@...il.com>
To:     Arnd Bergmann <arnd@...nel.org>, linux-omap@...r.kernel.org,
        tony@...mide.com, aaro.koskinen@....fi, jmkrzyszt@...il.com
Cc:     Arnd Bergmann <arnd@...db.de>,
        Russell King <linux@...linux.org.uk>,
        Paul Walmsley <paul@...an.com>,
        Kevin Hilman <khilman@...nel.org>,
        Vinod Koul <vkoul@...nel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Dominik Brodowski <linux@...inikbrodowski.net>,
        Mark Brown <broonie@...nel.org>,
        Felipe Balbi <balbi@...nel.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Helge Deller <deller@....de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org, dmaengine@...r.kernel.org,
        linux-input@...r.kernel.org, linux-mmc@...r.kernel.org,
        linux-serial@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, alsa-devel@...a-project.org
Subject: Re: [PATCH 19/41] ARM: omap: dma: make usb support optional



On 4/19/22 16:37, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> Most of the plat-omap/dma.c code is specific to the USB
> driver.

The reason is simple: the omap_udc is the only driver which has not been
ported to DMAengine.
I had a patch if I recall to convert it, but I don't have a way to test
it and the omap_udc sets some funky bits for DMA which we can not figure
out on how to handle.

> Hide that code when it is not in use, to make it
> clearer which parts are actually still required.

Reviewed-by: Peter Ujfalusi <peter.ujfalusi@...il.com>

> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  arch/arm/plat-omap/dma.c       | 45 +++++++++++++++++-----------------
>  drivers/usb/gadget/udc/Kconfig |  2 +-
>  include/linux/omap-dma.h       |  5 +++-
>  3 files changed, 27 insertions(+), 25 deletions(-)
> 
> diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> index 700ba9b600e7..b7757864d0aa 100644
> --- a/arch/arm/plat-omap/dma.c
> +++ b/arch/arm/plat-omap/dma.c
> @@ -66,7 +66,6 @@ enum { DMA_CHAIN_STARTED, DMA_CHAIN_NOTSTARTED };
>  
>  static struct omap_system_dma_plat_info *p;
>  static struct omap_dma_dev_attr *d;
> -static void omap_clear_dma(int lch);
>  static int enable_1510_mode;
>  static u32 errata;
>  
> @@ -90,19 +89,16 @@ static int omap_dma_reserve_channels;
>  static DEFINE_SPINLOCK(dma_chan_lock);
>  static struct omap_dma_lch *dma_chan;
>  
> -static inline void disable_lnk(int lch);
> -static void omap_disable_channel_irq(int lch);
> -static inline void omap_enable_channel_irq(int lch);
> -
> -#ifdef CONFIG_ARCH_OMAP15XX
> -/* Returns 1 if the DMA module is in OMAP1510-compatible mode, 0 otherwise */
> -static int omap_dma_in_1510_mode(void)
> +static inline void omap_disable_channel_irq(int lch)
>  {
> -	return enable_1510_mode;
> +	/* disable channel interrupts */
> +	p->dma_write(0, CICR, lch);
> +	/* Clear CSR */
> +	if (dma_omap1())
> +		p->dma_read(CSR, lch);
> +	else
> +		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
>  }
> -#else
> -#define omap_dma_in_1510_mode()		0
> -#endif
>  
>  #ifdef CONFIG_ARCH_OMAP1
>  static inline void set_gdma_dev(int req, int dev)
> @@ -169,6 +165,17 @@ void omap_set_dma_priority(int lch, int dst_port, int priority)
>  #endif
>  EXPORT_SYMBOL(omap_set_dma_priority);
>  
> +#if IS_ENABLED(CONFIG_USB_OMAP)
> +#ifdef CONFIG_ARCH_OMAP15XX
> +/* Returns 1 if the DMA module is in OMAP1510-compatible mode, 0 otherwise */
> +static int omap_dma_in_1510_mode(void)
> +{
> +	return enable_1510_mode;
> +}
> +#else
> +#define omap_dma_in_1510_mode()		0
> +#endif
> +
>  void omap_set_dma_transfer_params(int lch, int data_type, int elem_count,
>  				  int frame_count, int sync_mode,
>  				  int dma_trigger, int src_or_dst_synch)
> @@ -418,17 +425,6 @@ static inline void omap_enable_channel_irq(int lch)
>  	p->dma_write(dma_chan[lch].enabled_irqs, CICR, lch);
>  }
>  
> -static inline void omap_disable_channel_irq(int lch)
> -{
> -	/* disable channel interrupts */
> -	p->dma_write(0, CICR, lch);
> -	/* Clear CSR */
> -	if (dma_omap1())
> -		p->dma_read(CSR, lch);
> -	else
> -		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
> -}
> -
>  void omap_disable_dma_irq(int lch, u16 bits)
>  {
>  	dma_chan[lch].enabled_irqs &= ~bits;
> @@ -473,6 +469,7 @@ static inline void disable_lnk(int lch)
>  	p->dma_write(l, CLNK_CTRL, lch);
>  	dma_chan[lch].flags &= ~OMAP_DMA_ACTIVE;
>  }
> +#endif
>  
>  int omap_request_dma(int dev_id, const char *dev_name,
>  		     void (*callback)(int lch, u16 ch_status, void *data),
> @@ -572,6 +569,7 @@ static void omap_clear_dma(int lch)
>  	local_irq_restore(flags);
>  }
>  
> +#if IS_ENABLED(CONFIG_USB_OMAP)
>  void omap_start_dma(int lch)
>  {
>  	u32 l;
> @@ -792,6 +790,7 @@ int omap_get_dma_active_status(int lch)
>  	return (p->dma_read(CCR, lch) & OMAP_DMA_CCR_EN) != 0;
>  }
>  EXPORT_SYMBOL(omap_get_dma_active_status);
> +#endif
>  
>  int omap_dma_running(void)
>  {
> diff --git a/drivers/usb/gadget/udc/Kconfig b/drivers/usb/gadget/udc/Kconfig
> index cee934dce4f0..69394dc1cdfb 100644
> --- a/drivers/usb/gadget/udc/Kconfig
> +++ b/drivers/usb/gadget/udc/Kconfig
> @@ -128,7 +128,7 @@ config USB_GR_UDC
>  
>  config USB_OMAP
>  	tristate "OMAP USB Device Controller"
> -	depends on ARCH_OMAP1 || (ARCH_OMAP && COMPILE_TEST)
> +	depends on ARCH_OMAP1
>  	depends on ISP1301_OMAP || !(MACH_OMAP_H2 || MACH_OMAP_H3)
>  	help
>  	   Many Texas Instruments OMAP processors have flexible full
> diff --git a/include/linux/omap-dma.h b/include/linux/omap-dma.h
> index 5e228428fda1..07fa58ae9902 100644
> --- a/include/linux/omap-dma.h
> +++ b/include/linux/omap-dma.h
> @@ -299,8 +299,9 @@ extern void omap_set_dma_priority(int lch, int dst_port, int priority);
>  extern int omap_request_dma(int dev_id, const char *dev_name,
>  			void (*callback)(int lch, u16 ch_status, void *data),
>  			void *data, int *dma_ch);
> -extern void omap_disable_dma_irq(int ch, u16 irq_bits);
>  extern void omap_free_dma(int ch);
> +#if IS_ENABLED(CONFIG_USB_OMAP)
> +extern void omap_disable_dma_irq(int ch, u16 irq_bits);
>  extern void omap_start_dma(int lch);
>  extern void omap_stop_dma(int lch);
>  extern void omap_set_dma_transfer_params(int lch, int data_type,
> @@ -326,6 +327,8 @@ extern void omap_set_dma_dest_burst_mode(int lch,
>  extern dma_addr_t omap_get_dma_src_pos(int lch);
>  extern dma_addr_t omap_get_dma_dst_pos(int lch);
>  extern int omap_get_dma_active_status(int lch);
> +#endif
> +
>  extern int omap_dma_running(void);
>  
>  #if IS_ENABLED(CONFIG_FB_OMAP)

-- 
Péter