Re: [PATCH V2 2/2] PCI: brcmstb: support BCM4908 with external PERST# signal controller

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On 04.12.2020 19:21, Florian Fainelli wrote:
On 11/30/2020 12:32 AM, Rafał Miłecki wrote:
From: Rafał Miłecki <rafal@xxxxxxxxxx>

BCM4908 uses external MISC block for controlling PERST# signal. Use it
as a reset controller.

Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
V2: Reorder BCM4908 in the enum pcie_type
     Use devm_reset_control_get_optional_exclusive()
     Don't move hw_rev read up in the code
---
  drivers/pci/controller/Kconfig        |  2 +-
  drivers/pci/controller/pcie-brcmstb.c | 32 +++++++++++++++++++++++++++
  2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 64e2f5e379aa..d44c70bb88f6 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -273,7 +273,7 @@ config VMD
config PCIE_BRCMSTB
  	tristate "Broadcom Brcmstb PCIe host controller"
-	depends on ARCH_BRCMSTB || ARCH_BCM2835 || COMPILE_TEST
+	depends on ARCH_BRCMSTB || ARCH_BCM2835 || ARCH_BCM4908 || COMPILE_TEST
  	depends on OF
  	depends on PCI_MSI_IRQ_DOMAIN
  	default ARCH_BRCMSTB
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 9c3d2982248d..98536cf3af58 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -96,6 +96,7 @@
#define PCIE_MISC_REVISION 0x406c
  #define  BRCM_PCIE_HW_REV_33				0x0303
+#define  BRCM_PCIE_HW_REV_3_20				0x0320
#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT 0x4070
  #define  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_LIMIT_MASK	0xfff00000
@@ -190,6 +191,7 @@
  struct brcm_pcie;
  static inline void brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32 val);
  static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val);
+static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val);
  static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val);
  static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val);
@@ -206,6 +208,7 @@ enum { enum pcie_type {
  	GENERIC,
+	BCM4908,
  	BCM7278,
  	BCM2711,
  };
@@ -230,6 +233,13 @@ static const struct pcie_cfg_data generic_cfg = {
  	.bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
  };
+static const struct pcie_cfg_data bcm4908_cfg = {
+	.offsets	= pcie_offsets,
+	.type		= BCM4908,
+	.perst_set	= brcm_pcie_perst_set_4908,
+	.bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
+};
+
  static const int pcie_offset_bcm7278[] = {
  	[RGR1_SW_INIT_1] = 0xc010,
  	[EXT_CFG_INDEX] = 0x9000,
@@ -282,6 +292,7 @@ struct brcm_pcie {
  	const int		*reg_offsets;
  	enum pcie_type		type;
  	struct reset_control	*rescal;
+	struct reset_control	*perst_reset;
  	int			num_memc;
  	u64			memc_size[PCIE_BRCM_MAX_MEMC];
  	u32			hw_rev;
@@ -747,6 +758,17 @@ static inline void brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32
  	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
  }
+static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val)
+{
+	if (WARN_ONCE(!pcie->perst_reset, "missing PERST# reset controller\n"))
+		return;
+
+	if (val)
+		reset_control_assert(pcie->perst_reset);
+	else
+		reset_control_deassert(pcie->perst_reset);

This looks good to me now, just one nit, you probably do not support
suspend/resume on the 4908, likely never will, but you should probably
pulse the PERST# during PCIe resume, too. With that fixed:

Acked-by: Florian Fainelli <f.fainelli@xxxxxxxxx>

Driver already does that.

Suspend forward trace:
brcm_pcie_suspend()
brcm_pcie_turn_off()
pcie->perst_set(pcie, 1)

Resume forward trace:
brcm_pcie_resume()
brcm_pcie_setup()
pcie->perst_set(pcie, 0)

Correct me if I'm wrong please.



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