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From: 李晨阳 <lichenyang@loongson.cn>
To: "Huacai Chen" <chenhuacai@kernel.org>
Cc: "Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@linux.ie>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	LKML <linux-kernel@vger.kernel.org>,
	"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
	"Huacai Chen" <chenhuacai@loongson.cn>,
	"Tiezhu Yang" <yangtiezhu@loongson.cn>
Subject: Reply: Re: [PATCH v5] drm/loongson: Add DRM Driver for Loongson 7A1000 bridge chip
Date: Sat, 6 Mar 2021 14:48:26 +0800 (GMT+08:00)	[thread overview]
Message-ID: <42da178.aba.178064b600d.Coremail.lichenyang@loongson.cn> (raw)
In-Reply-To: <CAAhV-H5pv7aSEgGqCwOFHYQ7OH1dPa59XO4YEC7mFunhasrwgQ@mail.gmail.com>

&gt; &gt; +void ls7a_mm_wreg_locked(struct loongson_device *ldev, u32 offset, u32 val)
&gt; &gt; +{
&gt; &gt; +       unsigned long flags;
&gt; &gt; +
&gt; &gt; +       spin_lock_irqsave(&amp;ldev-&gt;mmio_lock, flags);
&gt; &gt; +       writel(val, ldev-&gt;mmio + offset);
&gt; &gt; +       spin_unlock_irqrestore(&amp;ldev-&gt;mmio_lock, flags);
&gt; &gt; +}
&gt; Why lock and disable irq? To workaround the hw issue from the first
&gt; revision of LS7A? If so, I suggest to remove the workaround. Because:
&gt; 1, mmio r/w will be used in irq context; 2, newer revision of LS7A
&gt; doesn't need workaround.
Yes,the lock is to workaround the hw issue,I have decided to remove the lock.
&gt; 
&gt; &gt; +
&gt; &gt; +       /* DC IO */
&gt; &gt; +       ldev-&gt;io = (void *)TO_UNCAC(LS7A_CHIPCFG_REG_BASE);
&gt; TO_UNCAC() is a MIPS-specific macro, I think ioremap() is better.
OK.I have switched to ioremap, and the test passed.
&gt; 
&gt; &gt; +#define LS7A_CHIPCFG_REG_BASE (0x10010000)
&gt; &gt; +#define PCI_DEVICE_ID_LOONGSON_DC 0x7a06
&gt; &gt; +#define PCI_DEVICE_ID_LOONGSON_GPU 0x7a15
&gt; They are already defined in include/linux/pci_ids.h.
In include/linux/pci_ids.h only defined PCI_VENDOR_ID_LOONGSON.

------------------------------
Loongson LiChenyang

      reply	other threads:[~2021-03-06  6:50 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210219091146.75364-1-lichenyang@loongson.cn>
2021-02-20  9:53 ` Huacai Chen
2021-03-06  6:48   ` 李晨阳 [this message]

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