From: Niklas Cassel <cassel@kernel.org>
To: Damien Le Moal <dlemoal@kernel.org>, Niklas Cassel <cassel@kernel.org>
Cc: Andrey Melnikov <temnota.am@gmail.com>, linux-ide@vger.kernel.org
Subject: [PATCH] ahci: print the number of implemented ports
Date: Wed, 14 Feb 2024 19:20:30 +0100 [thread overview]
Message-ID: <20240214182031.1004788-1-cassel@kernel.org> (raw)
We are currently printing the CAP.NP field.
CAP.NP is a 0's based value indicating the maximum number of ports
supported by the HBA silicon. Note that the number of ports indicated
in this field may be more than the number of ports indicated in the
PI (ports implemented) register. (See AHCI 1.3.1, section 3.1.1 -
Offset 00h: CAP – HBA Capabilities.)
Print the port_map instead, which is the value read by the PI (ports
implemented) register (after fixups).
PI (ports implemented) register is a field that has a bit set to '1'
if that specific port is implemented. This register is allowed to have
zeroes mixed with ones, i.e. a port in the middle is allowed to be
unimplemented. (See AHCI 1.3.1, section 3.1.4 - Offset 0Ch: PI – Ports
Implemented.)
Fix the libata print to only print the number of implemented ports,
instead of the theoretical number of ports supported by the HBA.
Suggested-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
drivers/ata/ahci.h | 11 +++++++++++
drivers/ata/libahci.c | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index df8f8a1a3a34..92d29a059763 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -455,4 +455,15 @@ static inline int ahci_nr_ports(u32 cap)
return (cap & 0x1f) + 1;
}
+static inline int ahci_nr_ports_in_map(u32 map)
+{
+ unsigned long port_map = map;
+ int i, n = 0;
+
+ for_each_set_bit(i, &port_map, AHCI_MAX_PORTS)
+ n++;
+
+ return n;
+}
+
#endif /* _AHCI_H */
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 1a63200ea437..82ebe911a327 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -2637,7 +2637,7 @@ void ahci_print_info(struct ata_host *host, const char *scc_s)
vers & 0xff,
((cap >> 8) & 0x1f) + 1,
- (cap & 0x1f) + 1,
+ ahci_nr_ports_in_map(impl),
speed_s,
impl,
scc_s);
--
2.43.0
next reply other threads:[~2024-02-14 18:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-14 18:20 Niklas Cassel [this message]
2024-02-14 19:33 ` [PATCH] ahci: print the number of implemented ports Sergei Shtylyov
2024-02-15 15:22 ` Sergei Shtylyov
2024-02-15 8:01 ` Andrey Melnikov
2024-02-15 8:22 ` Damien Le Moal
2024-02-15 11:19 ` Niklas Cassel
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