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Date: Tue, 12 Dec 2023 08:33:07 -0600
From: Tom Lendacky <thomas.lendacky@....com>
To: Raju Rangoju <Raju.Rangoju@....com>, netdev@...r.kernel.org
Cc: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, Shyam-sundar.S-k@....com
Subject: Re: [PATCH v3 net-next 1/3] amd-xgbe: reorganize the code of XPCS
access
On 12/11/23 23:37, Raju Rangoju wrote:
> The xgbe_{read/write}_mmd_regs_v* functions have common code which can
> be moved to helper functions. Also, the xgbe_pci_probe() needs
> reorganization.
>
> Add new helper functions to calculate the mmd_address for v1/v2 of xpcs
> access. And, convert if/else statements in xgbe_pci_probe() to switch
> case. This helps code look cleaner.
>
> Signed-off-by: Raju Rangoju <Raju.Rangoju@....com>
> ---
> drivers/net/ethernet/amd/xgbe/xgbe-dev.c | 43 ++++++++++++------------
> drivers/net/ethernet/amd/xgbe/xgbe-pci.c | 18 +++++++---
> 2 files changed, 34 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
> index f393228d41c7..6cd003c24a64 100644
> --- a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
> +++ b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
> @@ -1150,6 +1150,21 @@ static int xgbe_set_gpio(struct xgbe_prv_data *pdata, unsigned int gpio)
> return 0;
> }
>
> +static unsigned int get_mmd_address(struct xgbe_prv_data *pdata, int mmd_reg)
> +{
> + return (mmd_reg & XGBE_ADDR_C45) ?
> + mmd_reg & ~XGBE_ADDR_C45 :
> + (pdata->mdio_mmd << 16) | (mmd_reg & 0xffff);
> +}
> +
> +static unsigned int get_index_offset(struct xgbe_prv_data *pdata, unsigned int mmd_address,
> + unsigned int *index)
Just my opinion, but this looks confusing to me by updating index and returning
offset. And the name is confusing, too. I think it would read better as:
static void get_pcs_index_and_offset(struct xgbe_prv_data *pdata, unsigned int mmd_address,
unsigned int *index, unsigned int *offset)
{
mmd_address <<= 1;
*index = mmd_address & ~pdata->xpcs_window_mask;
*offset = pdata->xpcs_window + (mmd_address & pdata->xpcs_window_mask);
}
Or break this into two functions:
static unsigned int get_pcs_index(struct xgbe_prv_data *pdata, unsigned int mmd_address)
{
return (mmd_address << 1) & ~pdata->xpcs_window_mask;
}
static unsigned int get_pcs_offset(struct xgbe_prv_data *pdata, unsigned int mmd_address)
{
return pdata->xpcs_window + ((mmd_address << 1) & pdata->xpcs_window_mask);
}
> +{
> + mmd_address <<= 1;
> + *index = mmd_address & ~pdata->xpcs_window_mask;
> + return pdata->xpcs_window + (mmd_address & pdata->xpcs_window_mask);
> +}
> +
> static int xgbe_read_mmd_regs_v2(struct xgbe_prv_data *pdata, int prtad,
> int mmd_reg)
> {
> @@ -1157,10 +1172,7 @@ static int xgbe_read_mmd_regs_v2(struct xgbe_prv_data *pdata, int prtad,
> unsigned int mmd_address, index, offset;
> int mmd_data;
>
> - if (mmd_reg & XGBE_ADDR_C45)
> - mmd_address = mmd_reg & ~XGBE_ADDR_C45;
> - else
> - mmd_address = (pdata->mdio_mmd << 16) | (mmd_reg & 0xffff);
> + mmd_address = get_mmd_address(pdata, mmd_reg);
>
> /* The PCS registers are accessed using mmio. The underlying
> * management interface uses indirect addressing to access the MMD
> @@ -1171,9 +1183,7 @@ static int xgbe_read_mmd_regs_v2(struct xgbe_prv_data *pdata, int prtad,
> * register offsets must therefore be adjusted by left shifting the
> * offset 1 bit and reading 16 bits of data.
> */
> - mmd_address <<= 1;
> - index = mmd_address & ~pdata->xpcs_window_mask;
> - offset = pdata->xpcs_window + (mmd_address & pdata->xpcs_window_mask);
> + offset = get_index_offset(pdata, mmd_address, &index);
The comment above this code should be moved into the new helper and then
removed here and below.
>
> spin_lock_irqsave(&pdata->xpcs_lock, flags);
> XPCS32_IOWRITE(pdata, pdata->xpcs_window_sel_reg, index);
> @@ -1189,10 +1199,7 @@ static void xgbe_write_mmd_regs_v2(struct xgbe_prv_data *pdata, int prtad,
> unsigned long flags;
> unsigned int mmd_address, index, offset;
>
> - if (mmd_reg & XGBE_ADDR_C45)
> - mmd_address = mmd_reg & ~XGBE_ADDR_C45;
> - else
> - mmd_address = (pdata->mdio_mmd << 16) | (mmd_reg & 0xffff);
> + mmd_address = get_mmd_address(pdata, mmd_reg);
>
> /* The PCS registers are accessed using mmio. The underlying
> * management interface uses indirect addressing to access the MMD
> @@ -1203,9 +1210,7 @@ static void xgbe_write_mmd_regs_v2(struct xgbe_prv_data *pdata, int prtad,
> * register offsets must therefore be adjusted by left shifting the
> * offset 1 bit and writing 16 bits of data.
> */
> - mmd_address <<= 1;
> - index = mmd_address & ~pdata->xpcs_window_mask;
> - offset = pdata->xpcs_window + (mmd_address & pdata->xpcs_window_mask);
> + offset = get_index_offset(pdata, mmd_address, &index);
>
> spin_lock_irqsave(&pdata->xpcs_lock, flags);
> XPCS32_IOWRITE(pdata, pdata->xpcs_window_sel_reg, index);
> @@ -1220,10 +1225,7 @@ static int xgbe_read_mmd_regs_v1(struct xgbe_prv_data *pdata, int prtad,
> unsigned int mmd_address;
> int mmd_data;
>
> - if (mmd_reg & XGBE_ADDR_C45)
> - mmd_address = mmd_reg & ~XGBE_ADDR_C45;
> - else
> - mmd_address = (pdata->mdio_mmd << 16) | (mmd_reg & 0xffff);
> + mmd_address = get_mmd_address(pdata, mmd_reg);
>
> /* The PCS registers are accessed using mmio. The underlying APB3
> * management interface uses indirect addressing to access the MMD
> @@ -1248,10 +1250,7 @@ static void xgbe_write_mmd_regs_v1(struct xgbe_prv_data *pdata, int prtad,
> unsigned int mmd_address;
> unsigned long flags;
>
> - if (mmd_reg & XGBE_ADDR_C45)
> - mmd_address = mmd_reg & ~XGBE_ADDR_C45;
> - else
> - mmd_address = (pdata->mdio_mmd << 16) | (mmd_reg & 0xffff);
> + mmd_address = get_mmd_address(pdata, mmd_reg);
>
> /* The PCS registers are accessed using mmio. The underlying APB3
> * management interface uses indirect addressing to access the MMD
> diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-pci.c b/drivers/net/ethernet/amd/xgbe/xgbe-pci.c
> index f409d7bd1f1e..8b0c1e450b7e 100644
> --- a/drivers/net/ethernet/amd/xgbe/xgbe-pci.c
> +++ b/drivers/net/ethernet/amd/xgbe/xgbe-pci.c
> @@ -274,12 +274,18 @@ static int xgbe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>
> /* Set the PCS indirect addressing definition registers */
> rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
> - if (rdev &&
> - (rdev->vendor == PCI_VENDOR_ID_AMD) && (rdev->device == 0x15d0)) {
> +
> + if (!(rdev && rdev->vendor == PCI_VENDOR_ID_AMD)) {
> + ret = -ENODEV;
> + goto err_pci_enable;
> + }
This is different behavior compared to today. Today, everything would
default to the final "else" statement. With this patch you have a
possibility of failing probe now.
Thanks,
Tom
> +
> + switch (rdev->device) {
> + case 0x15d0:
> pdata->xpcs_window_def_reg = PCS_V2_RV_WINDOW_DEF;
> pdata->xpcs_window_sel_reg = PCS_V2_RV_WINDOW_SELECT;
> - } else if (rdev && (rdev->vendor == PCI_VENDOR_ID_AMD) &&
> - (rdev->device == 0x14b5)) {
> + break;
> + case 0x14b5:
> pdata->xpcs_window_def_reg = PCS_V2_YC_WINDOW_DEF;
> pdata->xpcs_window_sel_reg = PCS_V2_YC_WINDOW_SELECT;
>
> @@ -288,9 +294,11 @@ static int xgbe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>
> /* Yellow Carp devices do not need rrc */
> pdata->vdata->enable_rrc = 0;
> - } else {
> + break;
> + default:
> pdata->xpcs_window_def_reg = PCS_V2_WINDOW_DEF;
> pdata->xpcs_window_sel_reg = PCS_V2_WINDOW_SELECT;
> + break;
> }
> pci_dev_put(rdev);
>
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