[PATCH linux dev-5.4] fsi: aspeed: Enable 23-bit addressing

[PATCH linux dev-5.4] fsi: aspeed: Enable 23-bit addressing

[Eddie James]

In order to access more than the second hub link, 23-bit addressing is
required. The core provides the highest two bits of address as the slave
ID to the master.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/fsi/fsi-master-aspeed.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
index 12e48f6..90c2e4e 100644
--- a/drivers/fsi/fsi-master-aspeed.c
+++ b/drivers/fsi/fsi-master-aspeed.c
@@ -241,9 +241,10 @@ static int aspeed_master_read(struct fsi_master *master, int link,
 	struct fsi_master_aspeed *aspeed = to_fsi_master_aspeed(master);
 	int ret;
 
-	if (id != 0)
+	if (id > 0x3)
 		return -EINVAL;
 
+	addr |= id << 21;
 	addr += link * FSI_HUB_LINK_SIZE;
 
 	switch (size) {
@@ -273,9 +274,10 @@ static int aspeed_master_write(struct fsi_master *master, int link,
 	struct fsi_master_aspeed *aspeed = to_fsi_master_aspeed(master);
 	int ret;
 
-	if (id != 0)
+	if (id > 0x3)
 		return -EINVAL;
 
+	addr |= id << 21;
 	addr += link * FSI_HUB_LINK_SIZE;
 
 	switch (size) {
-- 
1.8.3.1

Re: [PATCH linux dev-5.4] fsi: aspeed: Enable 23-bit addressing

[Jeremy Kerr]

Hi Eddie,

> In order to access more than the second hub link, 23-bit addressing is
> required. The core provides the highest two bits of address as the slave
> ID to the master.

Looks good, this is just the reverse of the encoding we set up in
fsi_slave_calc_addr().

Acked-by: Jeremy Kerr <jk@ozlabs.org>

[I assume that the opb area is large enough for the 23-bit
addressing...]

Cheers,


Jeremy

Re: [PATCH linux dev-5.4] fsi: aspeed: Enable 23-bit addressing

[Joel Stanley]

On Tue, 31 Mar 2020 at 05:23, Jeremy Kerr <jk@ozlabs.org> wrote:
>
> Hi Eddie,
>
> > In order to access more than the second hub link, 23-bit addressing is
> > required. The core provides the highest two bits of address as the slave
> > ID to the master.
>
> Looks good, this is just the reverse of the encoding we set up in
> fsi_slave_calc_addr().
>
> Acked-by: Jeremy Kerr <jk@ozlabs.org>

Thanks Jeremy.

> [I assume that the opb area is large enough for the 23-bit
> addressing...]

On the AST2600 the AHB to OPB bridge sets the OBP base address to
0xa0000000, so we have plenty of address space to use. Is that what
you're referring to, or have I misunderstood?

Cheers,

Joel