[RFC,1/9] PCI: pci-bridge-emul: Update PCIe register behaviors
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Message ID 1581120007-5280-2-git-send-email-jonathan.derrick@intel.com
State New
Headers show
Series
  • PCIe Hotplug Slot Emulation driver
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Commit Message

Derrick, Jonathan Feb. 7, 2020, 11:59 p.m. UTC
Update the PCIe register behaviors and comments for PCIe v5.0.
Replace the specific bit definitions with BIT and GENMASK to make
updating easier in the future.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 drivers/pci/pci-bridge-emul.c | 54 +++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 27 deletions(-)

Comments

Andy Shevchenko Feb. 8, 2020, 9:55 a.m. UTC | #1
On Sat, Feb 8, 2020 at 2:02 AM Jon Derrick <jonathan.derrick@intel.com> wrote:
>
> Update the PCIe register behaviors and comments for PCIe v5.0.

I think you may elaborate the changes here, like a summary.

> Replace the specific bit definitions with BIT and GENMASK to make
> updating easier in the future.

...

> +                * Device status register has bits 6 and [3:0] W1C, [5:4] RO,
> +                * the rest is reserved

Perhaps it makes sense to add '.' (period) to the end of sentence. And
the same for the rest comments.

...

> -               .w1c = (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
> -                       PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC |
> -                       PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC) << 16,
> -               .ro = (PCI_EXP_SLTSTA_MRLSS | PCI_EXP_SLTSTA_PDS |
> -                      PCI_EXP_SLTSTA_EIS) << 16,

> +               .w1c = (BIT(8) | GENMASK(4, 0)) << 16,
> +               .ro = GENMASK(7, 5) << 16,

I'm not sure the new one is better. Perhaps you need to add
description for the new bits and, if you consider it's needed, add a
picture of the bits in the comment, like  XXXX rwX1 XXrX XwXX, where r
= ro, w = rw, 1 = w1c, X = rsvd. But it's up to Bjorn and you, I have
no strong opinion here.

Same for the rest similar changes.

...

> -               .rw = (PCI_EXP_RTCTL_SECEE | PCI_EXP_RTCTL_SENFEE |
> -                      PCI_EXP_RTCTL_SEFEE | PCI_EXP_RTCTL_PMEIE |
> -                      PCI_EXP_RTCTL_CRSSVE),
> -               .ro = PCI_EXP_RTCAP_CRSVIS << 16,
> +               .rw = GENMASK(4, 0),
> +               .ro = BIT(0) << 16,

Bit 0 in both rw and ro -- is it correct?

Patch
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diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
index fffa770..d065c2a 100644
--- a/drivers/pci/pci-bridge-emul.c
+++ b/drivers/pci/pci-bridge-emul.c
@@ -191,12 +191,12 @@  struct pci_bridge_reg_behavior {
 		.rw = GENMASK(15, 0),
 
 		/*
-		 * Device status register has 4 bits W1C, then 2 bits
-		 * RO, the rest is reserved
+		 * Device status register has bits 6 and [3:0] W1C, [5:4] RO,
+		 * the rest is reserved
 		 */
-		.w1c = GENMASK(19, 16),
-		.ro = GENMASK(20, 19),
-		.rsvd = GENMASK(31, 21),
+		.w1c = (BIT(6) | GENMASK(3, 0)) << 16,
+		.ro = GENMASK(5, 4) << 16,
+		.rsvd = GENMASK(15, 7) << 16,
 	},
 
 	[PCI_EXP_LNKCAP / 4] = {
@@ -207,15 +207,16 @@  struct pci_bridge_reg_behavior {
 
 	[PCI_EXP_LNKCTL / 4] = {
 		/*
-		 * Link control has bits [1:0] and [11:3] RW, the
-		 * other bits are reserved.
-		 * Link status has bits [13:0] RO, and bits [14:15]
+		 * Link control has bits [15:14], [11:3] and [1:0] RW, the
+		 * rest is reserved.
+		 *
+		 * Link status has bits [13:0] RO, and bits [15:14]
 		 * W1C.
 		 */
-		.rw = GENMASK(11, 3) | GENMASK(1, 0),
+		.rw = GENMASK(15, 14) | GENMASK(11, 3) | GENMASK(1, 0),
 		.ro = GENMASK(13, 0) << 16,
 		.w1c = GENMASK(15, 14) << 16,
-		.rsvd = GENMASK(15, 12) | BIT(2),
+		.rsvd = GENMASK(13, 12) | BIT(2),
 	},
 
 	[PCI_EXP_SLTCAP / 4] = {
@@ -224,19 +225,16 @@  struct pci_bridge_reg_behavior {
 
 	[PCI_EXP_SLTCTL / 4] = {
 		/*
-		 * Slot control has bits [12:0] RW, the rest is
+		 * Slot control has bits [14:0] RW, the rest is
 		 * reserved.
 		 *
-		 * Slot status has a mix of W1C and RO bits, as well
-		 * as reserved bits.
+		 * Slot status has bits 8 and [4:0] W1C, bits [7:5] RO, the
+		 * rest is reserved.
 		 */
-		.rw = GENMASK(12, 0),
-		.w1c = (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
-			PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC |
-			PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC) << 16,
-		.ro = (PCI_EXP_SLTSTA_MRLSS | PCI_EXP_SLTSTA_PDS |
-		       PCI_EXP_SLTSTA_EIS) << 16,
-		.rsvd = GENMASK(15, 12) | (GENMASK(15, 9) << 16),
+		.rw = GENMASK(14, 0),
+		.w1c = (BIT(8) | GENMASK(4, 0)) << 16,
+		.ro = GENMASK(7, 5) << 16,
+		.rsvd = BIT(15) | (GENMASK(15, 9) << 16),
 	},
 
 	[PCI_EXP_RTCTL / 4] = {
@@ -244,18 +242,20 @@  struct pci_bridge_reg_behavior {
 		 * Root control has bits [4:0] RW, the rest is
 		 * reserved.
 		 *
-		 * Root status has bit 0 RO, the rest is reserved.
+		 * Root capabilities has bit 0 RO, the rest is reserved.
 		 */
-		.rw = (PCI_EXP_RTCTL_SECEE | PCI_EXP_RTCTL_SENFEE |
-		       PCI_EXP_RTCTL_SEFEE | PCI_EXP_RTCTL_PMEIE |
-		       PCI_EXP_RTCTL_CRSSVE),
-		.ro = PCI_EXP_RTCAP_CRSVIS << 16,
+		.rw = GENMASK(4, 0),
+		.ro = BIT(0) << 16,
 		.rsvd = GENMASK(15, 5) | (GENMASK(15, 1) << 16),
 	},
 
 	[PCI_EXP_RTSTA / 4] = {
-		.ro = GENMASK(15, 0) | PCI_EXP_RTSTA_PENDING,
-		.w1c = PCI_EXP_RTSTA_PME,
+		/*
+		 * Root status has bits 17 and [15:0] RO, bit 16 W1C, the rest
+		 * is reserved.
+		 */
+		.ro = BIT(17) | GENMASK(15, 0),
+		.w1c = BIT(16),
 		.rsvd = GENMASK(31, 18),
 	},
 };