Re: [RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg
From: Robin Murphy
Date: Thu Aug 27 2020 - 15:27:57 EST
On 2020-08-27 06:31, Yong Wu wrote:
On Wed, 2020-08-26 at 16:56 +0800, Miles Chen wrote:
In previous discussion [1] and [2], we found that it is risky to
use max_pfn or totalram_pages to tell if 4GB mode is enabled.
Check 4GB mode by reading infracfg register, remove the usage
of the un-exported symbol max_pfn.
This is a step towards building mtk_iommu as a kernel module.
[1] https://lore.kernel.org/lkml/20200603161132.2441-1-miles.chen@xxxxxxxxxxxx/
[2] https://lore.kernel.org/lkml/20200604080120.2628-1-miles.chen@xxxxxxxxxxxx/
[3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Yong Wu <yong.wu@xxxxxxxxxxxx>
Cc: Yingjoe Chen <yingjoe.chen@xxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx>
Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx>
---
Change since v3
- use lore.kernel.org links
- move "change since..." after "---"
Change since v2:
- determine compatible string by m4u_plat
- rebase to next-20200720
- add "---"
Change since v1:
- remove the phandle usage, search for infracfg instead [3]
- use infracfg instead of infracfg_regmap
- move infracfg definitaions to linux/soc/mediatek/infracfg.h
- update enable_4GB only when has_4gb_mode
---
drivers/iommu/mtk_iommu.c | 34 +++++++++++++++++++++++----
include/linux/soc/mediatek/infracfg.h | 3 +++
2 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 785b228d39a6..adc350150492 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -3,7 +3,6 @@
* Copyright (c) 2015-2016 MediaTek Inc.
* Author: Yong Wu <yong.wu@xxxxxxxxxxxx>
*/
-#include <linux/memblock.h>
#include <linux/bug.h>
#include <linux/clk.h>
#include <linux/component.h>
@@ -15,13 +14,16 @@
#include <linux/iommu.h>
#include <linux/iopoll.h>
#include <linux/list.h>
+#include <linux/mfd/syscon.h>
#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
+#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
+#include <linux/soc/mediatek/infracfg.h>
#include <asm/barrier.h>
#include <soc/mediatek/smi.h>
@@ -640,8 +642,11 @@ static int mtk_iommu_probe(struct platform_device *pdev)
struct resource *res;
resource_size_t ioaddr;
struct component_match *match = NULL;
+ struct regmap *infracfg;
void *protect;
int i, larb_nr, ret;
+ u32 val;
+ char *p;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
@@ -655,10 +660,29 @@ static int mtk_iommu_probe(struct platform_device *pdev)
return -ENOMEM;
data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
- /* Whether the current dram is over 4GB */
- data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
- if (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
- data->enable_4GB = false;
+ data->enable_4GB = false;
Nit: this isn't really necessary, since the structure is kzalloc()ed.
+ if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
+ switch (data->plat_data->m4u_plat) {
+ case M4U_MT2712:
+ p = "mediatek,mt2712-infracfg";
+ break;
+ case M4U_MT8173:
+ p = "mediatek,mt8173-infracfg";
+ break;
+ default:
+ p = NULL;
+ }
+
This can be simplified:
if (data->plat_data->m4u_plat == M4U_MT2712)
p = "mediatek,mt2712-infracfg";
else if(data->plat_data->m4u_plat == M4U_MT8173)
p = "mediatek,mt8173-infracfg";
else
return -EINVAL;
Right, at this point the HAS_4GB_MODE flag is entirely redundant and
should be removed. FWIW I still think your suggestion of putting the
infracfg names into plat_data would be even better and cleaner - there's
plenty of precedent for that sort of thing (see "git grep '\.clk_name'"
for example).
Robin.
Then,
Reviewed-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
+ infracfg = syscon_regmap_lookup_by_compatible(p);
+
+ if (IS_ERR(infracfg))
+ return PTR_ERR(infracfg);
+
+ ret = regmap_read(infracfg, REG_INFRA_MISC, &val);
+ if (ret)
+ return ret;
+ data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN);
+ }
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->base = devm_ioremap_resource(dev, res);
diff --git a/include/linux/soc/mediatek/infracfg.h b/include/linux/soc/mediatek/infracfg.h
index fd25f0148566..233463d789c6 100644
--- a/include/linux/soc/mediatek/infracfg.h
+++ b/include/linux/soc/mediatek/infracfg.h
@@ -32,6 +32,9 @@
#define MT7622_TOP_AXI_PROT_EN_WB (BIT(2) | BIT(6) | \
BIT(7) | BIT(8))
+#define REG_INFRA_MISC 0xf00
+#define F_DDR_4GB_SUPPORT_EN BIT(13)
+
int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
bool reg_update);
int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,
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